www.osram.com
Metal
halide lamps
Instructions for the use and application
2
1
I
ntr
oduc
t
io
n..
.
.................................................................................................................................................
4
2
H
ow a meta
l
h
a
lid
e
l
amp wor
ks
......................................................................................................................
5
2
.
1
Q
uartz discharge tub
e
.............................................................................................................................
6
2.2
C
eramic dischar
g
e tube
(
P
C
A = polycrystalline alumina
)
.........................................................................
6
2.2.
1
1st
g
eneration: cylindrical
f
or
m
.....................................................................................................
6
2.2.2 2nd
g
eneration: freely moldable ceramic, P
O
WERBALL
................................................................
6
3
Ballasts
f
or discharge lamp
s
..........................................................................................................................
8
3
.
1
Inductive ballasts
(
chokes
)
......................................................................................................................
8
3
.1.
1
A
m
e
ri
ca
n
c
ir
cu
it
s
fo
r
ba
ll
as
t
s
........................................................................................................
9
3
.
1
.
2
Variation in supply volta
g
e
f
or adapted inductanc
e
.....................................................................
10
3
.
1
.
3
In
f
luence o
f
deviations in supply voltag
e
.....................................................................................
11
3
.1.
4
C
a
p
acitor for
p
ower factor correctio
n
.........................................................................................
11
3
.
2
Electronic control
g
ear
(
E
CG)
................................................................................................................
12
3
.
2
.
1
S
tructure and functionin
g
of an electronic ballast
.
......................................................................
12
3
.
2
.
2
S
ervice life and tem
p
erature
.......................................................................................................
13
3
.2.
3
A
dvanta
g
es of operation with electronic ballast P
O
WERTR
O
NI
C
PTi
..........................................
1
3
3
.
3
In
f
luence o
f
harmonic waves and correspondin
g
f
ilter
s
.........................................................................
1
5
3
.
4
Brie
f
volta
g
e interruption
s
.....................................................................................................................
16
3
.
5
S
trobosco
p
ic effect and flicke
r
.............................................................................................................
17
4
Ig
n
i
t
i
n
g
an
d
start
i
n
g
di
sc
h
ar
g
e
l
amp
s
...........................................................................................................
1
9
4.1
E
xterna
l
ig
n
i
t
i
on un
i
t
s
...........................................................................................................................
1
9
4
.
1
.
1
P
ara
ll
e
l
ig
n
i
t
i
on un
it
....................................................................................................................
19
4
.
1
.
2
S
emi-parallel i
g
nition uni
t
...........................................................................................................
19
4.1.
3
S
uperimposed i
g
nitor
.................................................................................................................
2
0
4.2
W
arm re-
ig
n
i
t
i
o
n
...................................................................................................................................
2
0
4
.
3
H
ot re-
ig
n
i
t
i
o
n
.......................................................................................................................................
20
4.4 I
g
nition at low i
g
nition volta
g
e
(
Pennin
g
effect
)
.....................................................................................
2
0
4.
5
I
gn
i
t
i
on at
l
ow am
bi
ent temperature
s
....................................................................................................
2
0
4.
6
Cable ca
p
acitanc
e
................................................................................................................................
21
4
.
7
S
tart-up behavior of metal halide lamp
s
................................................................................................
21
5
Reducing the wattage o
f
high intensity discharge lamp
s
..............................................................................
23
5
.
1
I
ntr
oduc
t
ion
..........................................................................................................................................
2
3
5
.
2
W
atta
g
e re
d
uct
i
on tec
h
n
i
que
s
...............................................................................................................
2
3
5
.
2
.
1
R
e
d
uc
i
n
g
t
h
e supp
l
y vo
l
ta
ge
.......................................................................................................
23
5.
2
.
2
Ph
ase contro
l
:
l
ea
di
ng e
d
ge, tra
ili
ng e
d
g
e
..................................................................................
24
5
.2.
3
I
ncreas
i
n
g
c
h
o
k
e
i
mpe
d
ance or
d
ecreas
i
n
g
l
amp curren
t
............................................................
24
5
.2.4
C
han
g
e in frequency for hi
g
h-frequency mod
e
............................................................................
24
5
.
3
Recommendations
f
or reducin
g
the watta
g
e in dischar
g
e lamp
s
...........................................................
25
5.
3
.
1
M
eta
l
h
a
lid
e
l
am
ps
.....................................................................................................................
25
5.3.
2
Dimming
f
or other discharge lamp
s
............................................................................................
2
5
6
Lamp service life, a
g
in
g
and failure behavior
................................................................................................
2
6
6
.
1
Lamp service li
f
e and a
g
in
g
behavior
....................................................................................................
26
6
.
2
S
torage of metal halide lamps
...............................................................................................................
26
6.3 Failure mechanisms o
f
metal halide lam
p
s
............................................................................................
2
6
Co
ntent
s
3
6.3.
1
L
ea
ki
ng arc tu
be
.........................................................................................................................
27
6.3.
2
I
ncrease
i
n re-
i
gn
i
t
i
on pea
k
.........................................................................................................
27
6.3.3
B
ro
k
en
l
ea
d
or
b
ro
k
en we
ld
........................................................................................................
2
8
6
.
3
.
4
L
ea
ki
n
g
outer
b
u
lb
......................................................................................................................
2
8
6
.
3
.
5
L
amps t
h
at
d
o not
ig
n
i
t
e
.............................................................................................................
2
8
6
.
3
.
6
Breaka
g
e or di
ff
erin
g
wear o
f
the electrodes
...............................................................................
29
6
.
3
.
7
S
calin
g
of the base
/
socke
t
.......................................................................................................
29
6
.
3
.
8
Burstin
g
o
f
the lam
p
...................................................................................................................
29
6
.
3
.
9
Recti
f
yin
g
e
ff
ec
t
........................................................................................................................
.
29
6
.
3
.10
C
onclusion
s
................................................................................................................................
31
7
Luminaire desi
g
n and plannin
g
o
f
li
g
htin
g
system
s
.......................................................................................
32
7.1
M
easur
i
n
g
temperatures, am
bi
ent temperatur
e
.....................................................................................
3
2
7.1.1
G
eneral ph
y
sical conditions for temperature limits for outer bulbs
and
p
inches in metal halide lam
ps
..............................................................................................
32
7.1.2
2 Measurement with thermocou
p
l
e
.............................................................................................
32
7.1.
3
Measurin
g
points
f
or thermocouples in di
ff
erent lamp types
.......................................................
33
7.2
In
f
luence o
f
ambient tem
p
erature on ballasts and luminaire
s
................................................................
36
7.
3
L
am
p
h
o
ld
e
r
.........................................................................................................................................
36
7.
4
Leads
t
o
lu
m
i
n
ai
r
es
...............................................................................................................................
37
7
.
5
Maintenance o
f
li
g
htin
g
systems with metal halide lamp
s
.....................................................................
.
37
7.
6
S
tandards and directives for dischar
g
e lamp
s
......................................................................................
.
39
7.
6
.
1
S
tandard
s
...................................................................................................................................
39
7.
6
.
2
Di
r
ec
t
i
v
es
...................................................................................................................................
41
7.
6
.
3
C
ertificate
s
.................................................................................................................................
41
7.7
R
ad
i
o
int
e
r
fe
r
e
n
ce
................................................................................................................................
42
7.
8
RoH
S
conformit
y
..................................................................................................................................
42
7.
9
O
ptical design of reflector
s
...................................................................................................................
42
7.
9
.
1
C
ondensation on the lam
p
..........................................................................................................
42
7.
9
.
2
Pro
j
ection o
f
the condensat
e
......................................................................................................
42
7.
9
.
3
Back re
f
lection on the lam
p
........................................................................................................
43
8
Ligh
t an
d
co
l
ou
r
..........................................................................................................................................
.
43
8
.
1
Nigh
t v
i
s
i
o
n
..........................................................................................................................................
.
44
8
.
2
C
olour renderin
g
..................................................................................................................................
.
46
8
.
2
.
1
Test colours
f
rom standard DIN 6169 .........................................................................................
.
47
8.
3
Li
g
ht and quality o
f
li
fe
.........................................................................................................................
48
8
.4
UV
ra
di
at
i
o
n
..........................................................................................................................................
49
8
.4.
1
Fading e
ff
ec
t
..............................................................................................................................
50
8.4.
2
Protective measures to reduce
f
adin
g
.........................................................................................
5
0
9
Disposal o
f
dischar
g
e lamp
s
.........................................................................................................................
51
9
.
1
S
tatutor
y
requirement
s
.........................................................................................................................
51
9
.
2
C
ollection, transport and disposal of dischar
g
e lamps at end-of-lif
e
....................................................
.
51
9
.
3
O
rdinance on Hazardous
S
ubstance
s
..................................................................................................
.
51
10
Li
s
t
of
abb
r
e
vi
a
ti
o
n
s
....................................................................................................................................
.
52
11
Li
t
e
r
a
t
u
r
e
....................................................................................................................................................
.
53
4
1 Intr
o
duct
ion
T
he means o
f
g
eneratin
g
li
g
ht is technically com-
p
li
cate
d
.
Th
e
k
ey pr
i
nc
i
p
l
es re
g
ar
di
n
g
t
h
e opera-
tion o
f
these lam
p
s and instructions
f
or their use
a
r
e
lis
t
ed
belo
w
.
Th
ese app
li
cat
i
on
i
nstruct
i
ons a
dd
ress a
l
ar
g
e num
b
er
o
f
users, such as luminaire desi
g
ners, li
g
htin
g
plannin
g
en
gi
neers, operat
i
n
g
d
ev
i
ce
d
eve
l
opers an
d
reta
il
ers.
Naturall
y
, not all users will
f
ind all sections relevant,
but the aim has been to cover the interests o
f
as man
y
users as
p
oss
ibl
e
.
Metal halide lamps o
ff
er a number o
f
advantages that
f
avor their use in ever broader areas o
f
a
pp
lication.
T
hese include hi
g
h luminous e
ff
icacy, a lon
g
service
li
f
e and
g
ood colour renderin
g
. Because the li
g
ht is
g
enerate
d
i
n a sma
ll
space, t
h
e
di
sc
h
arge
l
amps
al
most correspon
d
to a spot
ligh
t source, w
i
t
h
a
dvanta
g
es in terms o
f
li
g
ht control and brilliance
of
th
e
ill
u
min
a
ti
o
n
.
Table 1: The properties o
f
metal halide lamps and resultin
g
application areas
R
e
q
u
i
rements
i
n t
h
e
app
li
cat
i
o
n
Propert
y
o
f
meta
l
h
a
lid
e
l
amp
s
Hi
g
h
room,
b
u
ildi
n
g
S
ho
p
S
tree
t
B
u
ildi
ng
illu
m
i
n
a
t
ion
Sp
orts
fac
iliti
es
I
n
d
ustr
y
T
r
ade
sho
w
F
o
y
e
r
The hei
g
ht requires a lot o
f
li
g
ht
Hi
g
h luminous
fl
ux permits
f
ew
fi
xtures li
g
ht point
s
X
X
X
X
X
Chan
g
in
g
lamps is diffi cult and
expens
i
v
e
Lon
g
service li
f
e with lon
g
er
c
h
an
g
e
i
nterva
l
s
X
X
X
X
X
X
L
on
g
operat
i
n
g
h
ours
Hi
g
h e
ffi
cacy and lon
g
se
rvi
ce
li
fe
X
X
X
X
X
Realistic reproduction o
f
hi
g
h
value sur
f
aces, pictures,
products and TV ima
g
e
s
G
ood colour renderin
g
X
X
X
Hi
g
h illuminance values
High luminous
fl
ux permits
f
ew
fi
xtures li
g
ht point
s
X
X
Lu
m
i
n
ai
r
es
should
be
s
m
all
or
di
scree
t
S
mall dimensions permit
com
p
act
l
um
i
na
i
re
s
X
X
X
Hi
g
h
mount
i
ng
h
e
i
g
h
ts an
d
w
id
e spac
i
n
g
d
eman
d
prec
i
se
ligh
t contro
l
Small arc tubes permit ver
y
g
oo
d
ligh
t contro
l
X
X
X
5
2 How a metal hal
i
de lam
p
work
s
Contact plate
UV-Filter
Quter bulb
(Quartz)
Molybdenum foil
Arc tube
(Quartz)
Discharge arc
Heat reector
Lead-in wire
Molybdenum foil
Base
Getter
Metal halides
Mercury
Electrode
Fi
g
. 1: An example o
f
how a metal halide lamp works
b
ase
d
on a
d
ou
bl
e-en
d
e
d
l
am
p
w
i
t
h
a
q
uartz arc tu
b
e.
S
imilar to hi
g
h-pressure mercury lamps or hi
g
h-pres
-
sure so
di
um
l
amps, meta
l
h
a
lid
e
l
amps a
l
so
b
e
l
on
g
to
the group of discharge lamps. Low pressure discharge
lam
p
s include
f
luorescent lam
p
s and com
p
act
f
luores-
cent
l
amps
.
I
n
di
sc
h
ar
g
e
l
amps,
ligh
t
i
s
g
enerate
d
b
y a
g
as
di
s-
char
g
e o
f
particles created between two hermetically
sealed electrodes in an arc tube. A
f
ter ignition, the
part
i
c
l
es
i
n t
h
e arc are part
i
a
ll
y
i
on
i
ze
d
, ma
ki
n
g
t
h
em
e
l
ectr
i
ca
lly
con
d
uct
i
ve, an
d
a
“
p
l
asma
”
i
s create
d
.
I
n
high
i
ntens
i
ty
di
sc
h
ar
g
e
l
amps, t
h
e arc tu
b
e
i
s usua
ll
y
e
n
closed
i
n
a
n
e
v
acua
t
ed
ou
t
e
r
bulb
w
hich
isola
t
es
t
he
hot arc tube thermally
f
rom the surroundings, simila
r
to the
p
rinci
p
le o
f
a thermos
f
lask. But there are also
some
di
sc
h
ar
g
e
l
amps w
i
t
h
out outer
b
u
lb
s, as we
ll
as
lamps with
g
as-
f
illed outer bulbs. In contrast to low
-
pressure
di
sc
h
ar
g
e, t
h
ere
i
s
high
pressure an
d
a
high
temperature
i
n a
di
sc
h
ar
g
e tu
b
e.
I
n an arc tu
b
e,
g
as
di
sc
h
ar
g
e wor
k
s t
h
rou
gh
exc
i
tat
i
on
of the luminous additives
(
metal halide salts
)
and the
mercur
y
is excited b
y
the current
f
low. Visible radia
-
tion characteristic
f
or the res
p
ective elements is emit
-
t
ed
. Th
e
mixt
u
r
e
of
th
e
vi
s
i
b
l
e
r
ad
i
a
ti
o
n
of
th
e
d
i
ffe
r
e
nt
e
l
ements resu
l
ts
i
n t
h
e
d
es
ig
ne
d
co
l
our temperature
Outer bulb
Hg = Mercury
Me = Metals
Hal = Halids
Arc tube
Electrodes
Mo-Foils
supply voltage
Alternative: ECG
ignitor
ballast
Fi
g
. 2: Tasks of the metals [sodium (Na), thallium (TI), indium (In), tin (Sn), lithium (Li), rare earths; d
y
sprosium (D
y
),
h
olmium
(
Ho
)
, thulium
(
Tm
)]
and colour renderin
g
f
or a particular lamp. In the op
-
erat
i
n
g
state, t
h
e mercury evaporates comp
l
ete
l
y.
Th
e
other elements involved are present in saturated
f
orm
at t
h
e
gi
ven temperatures,
i
.e. t
h
ey on
l
y evaporate
i
n
p
art; the rest is in li
q
uid
f
orm at the coolest
p
oint in
the arc tube. The
f
raction o
f
the
f
illin
g
that has evapo-
rated depends on the temperature o
f
the coolest point
o
n th
e
a
r
c
t
ube
w
a
ll
a
n
d
a
l
so
v
a
ri
es
fo
r th
e
d
i
ffe
r
e
nt
fillin
g
components.
C
han
g
es to the temperature of the
arc tube wall can chan
g
e the composition o
f
the metal
halides in the dischar
g
e, thus also chan
g
in
g
the colour
p
ro
p
erties o
f
the lam
p
.
6
C
eramic arc tubes can be
p
roduced with smaller
di
mens
i
ona
l
to
l
erances, re
d
uc
i
ng t
h
e var
i
at
i
on
i
n
li
g
h
t-
tec
h
n
i
ca
l
an
d
e
l
ectr
i
ca
l
parameters
.
C
eramic is less susceptible to attacks from the a
g-
g
ressive metal halide
f
illin
g
and is less permeable
f
or
f
illing particles, resulting in a considerably longe
r
service li
f
e com
p
ared to
q
uartz tube lam
p
s.
C
eramic arc tubes are now available in various different
f
orms: the ori
g
inal cylindrical version and the improved
r
ou
n
d
v
e
r
s
i
o
n
.
2
.
2
.1 1st
g
enerat
i
on: cy
li
n
d
r
i
ca
l
f
or
m
In the
f
irst version, the ceramic arc tube was desi
g
ned
in a c
y
lindrical
f
orm, based on the production technol-
o
g
y
f
or the hi
g
h-pressure sodium lamp. The arc tube
was made up o
f
c
y
lindrical sub-sections sintered to-
g
ether. The arc tube consisted o
f
a relatively thick plu
g
at either end o
f
the tube: this was necessar
y
f
or the
durability and
f
unctionin
g
o
f
the tube
.
2
.
2
.
2
2
n
d
g
enerat
i
on:
f
ree
l
y mo
ld
a
bl
e ceram
i
c,
P
O
WERBAL
L
®
A
second step with changed production technology
permitted production o
f
f
reely moldable tube
g
eo-
m
etr
i
es.
Thi
s ma
d
e
i
t poss
ibl
e to pro
d
uce roun
d
ce-
r
a
m
ic
a
r
c
t
ubes
w
i
t
h
a
co
n
s
t
a
nt w
all
t
hick
n
ess
– t
he
P
O
WERBALL
®
a
r
c
t
ubes
. Th
e
r
ou
n
d
fo
rm
a
n
d
co
n
s
t
a
nt
wa
ll
t
hi
c
k
ness
b
roug
h
t cons
id
era
bl
e a
d
vantages.
Th
e
possibility o
f
f
urther increasin
g
the wall temperature
improves luminous e
ff
icacy and colour renderin
g
. The
absence o
f
the thick plu
g
at the end o
f
the tube re-
d
uces
ligh
t a
b
sorpt
i
on
i
n t
hi
s area, resu
l
t
i
n
g
i
n a
high
er
l
u
min
ous
f
l
u
x with m
o
r
e
u
ni
fo
rm irr
ad
i
a
ti
o
n
c
h
a
r
ac
t
e
r-
istics. There are
f
ewer di
ff
erences in the wall tem
p
era
-
ture
b
etween t
h
e var
i
ous
b
urn
i
n
g
pos
i
t
i
ons an
d
t
h
ere
-
fo
r
e
a
l
so
s
m
a
ll
e
r
d
i
ffe
r
e
n
ces
in
co
l
ou
r
be
tw
ee
n th
e
burnin
g
positions. The reduced ceramic mass o
f
the
round tube enables the tube to heat up
f
aster, reachin
g
the photometric values more quickl
y
. Similarl
y
, when
the lamp
g
oes o
ff
, warm re-i
g
nition is possible more
qu
i
c
kl
y
b
ecause t
h
e requ
i
re
d
coo
l
er start
i
n
g
tempera-
ture
f
or normal i
g
nition devices is achieved
f
aster
.
T
he uni
f
orm wall thickness and round sha
p
e
p
roduce a
m
ore even temperature curve a
l
on
g
t
h
e
i
nner tu
b
e wa
ll
as s
h
own
i
n
Fig
. 3,
b
ase
d
on t
h
e temperature s
h
own
i
n
co
l
ours
di
a
g
ram.
Th
e steeper temperature
g
ra
di
ent
i
n
the c
y
lindrical ceramic
f
avors chemical transport pro-
cesses. Durin
g
this process, aluminum oxide ceramic
di
sso
l
ves
i
n t
h
e
liq
u
id
meta
l
h
a
lid
e me
l
t an
d
sett
l
es
at cooler
p
oints o
f
the arc tube. I
f
erosion
f
rom the
wall
g
oes too
f
ar, this can lead to leaka
g
e in the tube,
causin
g
the lamp to
f
ail. Failures due to so-called
“ceramic corrosion” are thus less likel
y
to occur in
l
am
p
s w
i
t
h
roun
d
ceram
i
c tu
b
es
.
2.2 Ceramic discharge tube
(
P
C
A =
p
p
o
ly
c
r
y
sta
lli
ne
a
l
umina
)
Th
e
use
of
a
r
c
t
ubes
m
ade
of
ce
r
a
mi
c
m
a
t
e
ri
a
l
fu
rth
er
enhanced some of the metal halide lam
p
’s
p
ro
p
erties
.
C
eramic can withstand hi
g
her temperatures than
quartz
gl
ass.
Thi
s perm
i
ts
high
er wa
ll
temperatures
thereby evaporatin
g
more o
f
the metal halide salts into
the
g
as arc and allowin
g
for more efficient use of the
chemicals.
C
eramic lam
p
s offer im
p
roved luminous
e
ff
icacy and colour renderin
g
as a result
.
Daylight
Neutral White
Neutral White de luxe
Warm White de luxe
Variation possibilities of the Colour Temperature
Multiple lines
Multiple lines
GREEN
GREEN
YELLOW
YELLOW
RED
RED
BLUE
BLUE
Tn CRI
2.1 Quartz dischar
g
e tub
e
Th
e
di
sc
h
ar
g
e tu
b
es
i
n 1st-
g
enerat
i
on meta
l
h
a
lid
e
lamps are made o
f
hi
g
h purity quartz
g
lass. This quartz
material allows
f
or stable operation at hi
g
h tempera
-
tures, is resistant to sudden changes in temperature
and is trans
p
arent. The well
p
roven H
Q
I lam
p
s are
p
ro
-
duced in various di
ff
erent
f
orms usin
g
this technolo
g
y.
H ... Hydrar
g
yrum
(G
reek-Latin for mercury
)
Q
...
Q
uart
z
I ... I
od
i
de
•
W
e
ll
proven
l
amp tec
h
no
l
o
gy
•
Wid
e watta
g
e ran
g
e 7
0
W
–
2000
W
•
C
olour tem
p
eratures u
p
to 7250
K
•
G
ood o
p
tical
p
ro
p
erties thanks to trans
p
arent
di
sc
h
ar
g
e tu
be
Fi
g
. 2a:
G
eneration of the desired
S
pectral Distribution
C
omponents in order to achieve hi
g
h luminous Effica
-
cies and
g
ood
C
olour Renderin
g
7
The advantages of P
O
WERBAL
L
®
tec
h
no
l
ogy compare
d
to cy
li
n
d
r
i
ca
l
so
l
ut
i
ons
• Better maintained luminous
f
lux throu
g
hout the service li
f
e
•
I
mprove
d
co
l
or ren
d
er
i
n
g
, part
i
cu
l
ar
l
y
i
n t
h
e re
d
• Improved color stability durin
g
the service li
fe
• More uni
f
orm operation independent o
f
burnin
g
positio
n
• More constant luminous intensit
y
distributio
n
•
F
aster start-u
p
b
e
h
av
i
o
r
Fi
g
. 3:
C
omparison of ceramic corrosion between the different tube forms
9000 h
Convection
Deposition of alumina
by saturation of HM-melt
due to cooling
Condensation
of Metall Halides
Evaporation
of Metal Halides
Evaporation
of Metal Halides
Convection
Solution of
Alumina
in MH-melt
= Corrosion
Transport of
soluble
alumina in
MH-melt
Conden-
sation of
Metal Halides
1100
1060
1020
980
940
12000 h
8
3 Ballasts
f
or dischar
g
e lamp
s
C
PF
C
... PF
C
ca
p
acito
r
L
a ...
l
am
p
U
S
... supply volta
g
e
C
h ... chok
e
U
N
K
Dr
La
Ch
L
a
C
P
FC
U
S
Fig. 4: Discharge lamp with inductive ballast
(
ignition
u
nit has been le
f
t out, the various
p
ossibilities are
f
ea
-
tured in chapter 4 “I
g
nition and start-up o
f
dischar
g
e
l
amps”
)
C
hartin
g
the equations results in the curves shown in
Fi
g
. 5. The di
ff
erence between lamp watta
g
e and the
product of lamp voltage and lamp current is called
lam
p
p
ower
f
actor. It reaches values between 0.7 and
0.95
d
epen
di
n
g
on t
h
e operat
i
n
g
mo
d
e.
Th
e ye
ll
ow
curve was
g
enerate
d
b
y us
i
n
g
a
high
er
l
amp power
fac
t
o
r
λ
L
[(
to be more exact: 1.05*
(
1-n
/
3
)].
T
ypical volta
g
e and current wave
f
orms as shown in
Fig. 6 show that while the current is
(
approximately
)
sinusoidal, volta
g
e is not. A
f
ter the current zero cross
-
in
g
, the volta
g
e initially increases
(
so-called re-i
g
nition
peak
)
to then fall to a relativel
y
constant value
(
saddle
)
(
see also chapter 6.2.2 and Fi
g
. 30
)
. Volta
g
e remains
approximatel
y
the same be
y
ond the maximum o
f
the
current, an
d
h
as t
h
e same zero cross
i
n
g
as t
h
e current.
S
o there are areas with hi
g
h volta
g
e which count
towards the e
ff
ective value o
f
the volta
g
e but don’t
contr
ib
ute to t
h
e watta
g
e as t
h
e current at t
h
at po
i
nt
i
n
time is nearl
y
zero. This results in lamp power
f
actors
deviatin
g
f
rom the value 1
.
I
f
the lamp volta
g
e is equal to zero, the volta
g
e drop
across t
h
e c
h
o
k
e
i
s t
h
e ent
i
re supp
l
y vo
l
ta
g
e, an
d
t
h
e
choke
sho
rt-
ci
r
cui
t
cu
rr
e
nt
is
r
eached
.
This
is
t
he
m
a
x-
imum current that can
f
low throu
g
h the choke inas-
m
uc
h th
e
cu
rr
e
nt h
as
no
DC com
p
onent
(
see cha
p
ter
6
.2.9 for effects of direct current com
p
onents
).
T
he
f
ollowin
g
curves are typical
f
or 150 W and apply in
t
h
e same way to ot
h
er watta
g
es
.
Voltage in V
Current in A
Time in ms
Fi
g
. 6:
G
raph showin
g
lamp volta
g
e and current of a
150 W lam
p
when o
p
erated at a choke
(
a
pp
lies in the
same wa
y
to other watta
g
es
)
Fig
. 5:
L
amp current
I
L
,
l
amp watta
g
e
P
L
o
v
e
r t
he
r
a
t
io
o
f
lamp volta
g
e to suppl
y
volta
g
e U
L
/U
S
;
Z=99
Ω
fo
r
a
150
W
l
am
p
S
ince the dischar
g
e reacts to increasin
g
lamp current
with fallin
g
volta
g
e
(
which would cause the current to
rise indefinitel
y
until the fuse blows or another part o
f
the circuit fails
)
, the lamp current must be limited b
y
a ballast durin
g
operation. This usually consists o
f
an
inductive circuit
(
choke
)
, althou
g
h in rare cases up to
400 W capacitive circuits are also possible
(
althou
g
h
this usuall
y
results in a shorter service life
)
. In the
blended lam
p
(
HWL
)
, the resistance of the filament
serves as a series resistor
f
or the hi
g
h-pressure mer
-
cury
di
sc
h
ar
g
e
l
amp.
I
n most cases, a
ddi
t
i
ona
ll
y to t
h
e
current-
li
m
i
t
i
n
g
e
l
ement, an
ig
n
i
t
i
on
d
ev
i
ce
i
s nee
d
e
d
to start dischar
g
e
(
see chapter 4 “I
g
nition and startin
g
discharge lamps”
)
.
In modern luminaires
,
an electronic ballast
f
ul
f
ils the
f
unction o
f
i
g
nitin
g
the lamp, limitin
g
the lamp current
an
d
contro
lli
n
g
t
h
e
l
amp watta
g
e
.
3.1 Inductive ballasts
(
chokes
)
Th
e vo
l
ta
g
e across t
h
e e
l
ectroma
g
net
i
c
b
a
ll
ast
i
n
-
creases as the current increases
,
there
f
ore a stable
workin
g
point can be achieved in the series connec-
tion o
f
the dischar
g
e lamp and the choke
.
Describin
g
the relationships o
f
current and volta
g
e
requires a s
y
stem o
f
di
ff
erential equations which can
-
not
g
enerally be solved. The
f
ollowin
g
approximation
f
ormulas describe how the lamp current and lamp
watta
g
e depend on the relationship o
f
lamp volta
g
e to
supply volta
g
e
[
3
]:
P
L
..... lamp watta
g
e in W
U
S
..... supp
l
y vo
l
ta
g
e
i
n
V
n ..... ratio o
f
lamp volta
g
e
U
L
to supp
l
y vo
l
ta
g
e
U
S
Z
..... c
h
o
k
e
i
mpe
d
anc
e
(G
l. 4.1
)
n
n
Z
U
P
S
L
3
1
2
⎟
⎠
⎞
⎜
⎝
⎛
−⋅=
[]
n
)
n
225 ,01
2/1
2
−−
(
Z
U
I
S
L
[]
n
)
n
225 ,01
2/1
2
−−
(
≈
whereb
y
:
(
1-n
/
3
)
....approximation for the lam
p
p
ower factor
λ
L
(
Gl. 4.2
)
Lamp power P
in W
L
Lamp current I in A
180
160
140
120
100
80
60
40
20
0
2,5
2
1,5
1
0,5
0
0
0,5
1
U /U
L
S
L
5
%
hi
g
her lam
p
p
ower
f
acto
r
P
L
I
L
9
This lamp behavior results
f
rom the relativel
y
f
lat zero
crossin
g
f
or sinusoidal current. When the current ap
-
proac
h
es zero, t
h
e p
l
asma temperature
d
ecreases an
d
th
e
e
l
ec
tr
odes
a
l
so
coo
l
do
wn. Th
e
r
eco
m
b
in
a
ti
o
n
of
electrons with ions reduces conductivit
y
. A
f
ter the zero
crossing, the conductivity is too low to take up the
current t
h
at t
h
e c
h
o
k
e wants to
d
r
i
ve.
A
s a resu
l
t
,
t
h
e
volta
g
e throu
g
h the lamp increases a
g
ain si
g
ni
f
icantly
unt
il
t
h
e
l
amp
“
re
ig
n
i
tes
”
.
Th
e
high
er vo
l
ta
g
e resu
l
ts
i
n a
high
er
i
on
i
zat
i
on rate t
h
at
i
ncreases con
d
uct
i
v
i
ty
a
g
ain so that volta
g
e
f
alls.
By contrast, current and volta
g
e
f
or the rectan
g
ular
wave
f
orms o
f
an electronic ballast chan
g
e si
g
ni
f
i-
cantly
f
aster
f
rom positive to ne
g
ative hal
f
-wave, or
have a faster commutation times
(
see cha
p
ter 3.2
“
Electrical ballasts
(
E
CG)
”
)
, so that the
p
lasma has
li
tt
l
e c
h
ance to coo
l
d
own.
Th
e
i
nstantaneous vo
l
ta
g
e
required
f
rom the electronic ballast is there
f
ore si
g
-
ni
f
icantl
y
lower than
f
or the choke. This is one o
f
the
advanta
g
es o
f
electronic ballast, as one o
f
the
f
ailure
mechanisms o
f
metal halide lamps is to extin
g
uish
due to hi
g
h re-i
g
nition volta
g
e. The re-i
g
nition peak
o
f
a lamp normall
y
increases over the service li
f
e, and
w
h
en
i
t excee
d
s w
h
at t
h
e supp
l
y vo
l
ta
g
e momentar
il
y
can prov
id
e, t
h
ere
i
s no
“
re-
ig
n
i
t
i
on
”
an
d
t
h
e
l
amp
goes out
(
see also chapter 6.2.2 “Increase of the
re-i
g
nition peak”
).
Wh
en operat
i
n
g
on a convent
i
ona
l
c
h
o
k
e, t
h
e
l
amp
watta
g
e runs t
h
rou
gh
a max
i
mum
d
epen
di
n
g
on t
h
e
lamp volta
g
e
(
see Fi
g
. 5
)
. The maximum occurs for a
lamp volta
g
e o
f
sli
g
htly more than hal
f
the supply volt-
a
g
e.
N
ear t
h
e max
i
mum t
h
e
l
amp watta
g
e c
h
an
g
es
on
l
y s
ligh
t
l
y w
i
t
h
t
h
e
l
amp vo
l
ta
g
e.
D
ur
i
n
g
t
h
e
l
amp
service li
f
e, the lamp volta
g
e increases, as also shown
in chapter 6 “Lamp li
f
ecycle, a
g
in
g
and
f
ailure behav
-
ior”. In order
f
or the lamp watta
g
e to chan
g
e as little
as possible, the nominal value
f
or lamp voltage is gen
-
erall
y
chosen near the maximum, there
f
ore at about
hal
f
the supply volta
g
e.
The im
p
edance o
f
the choke is rated at a certain su
p
-
ply
f
requency and certain supply volta
g
e. Deviations
f
rom the nominal supply volta
g
e will result in a di
ff
er
-
ent ballast curve and a related di
ff
erent workin
g
point
f
or the lamp and there
f
ore di
ff
erent lamp watta
g
e. To
li
m
i
t t
h
e assoc
i
ate
d
g
reater sprea
d
i
n t
h
e
l
amp para
-
meters
,
a maximum deviation o
f
5
%
f
rom the nominal
values is permitted in the short term
f
or the suppl
y
volta
g
e, or maximum 3
%
in the lon
g
term. For devia
-
tions over a lon
g
er period o
f
time, suitable choke tap
must be selected.
S
imilarl
y
, the choke impedance
must not deviate
f
rom the nominal values b
y
more than
2%
(
see also cha
p
ter 3.1.3 “Influence of deviations in
supply volta
g
e”)
.
A
s
p
er the IE
C
61167 standard, ballast units for MH
lamps must by protected
f
rom overheatin
g
throu
g
h
recti
f
ication. This can be done e.
g
. with a thermal
f
use
(
tested accordin
g
to IE
C
598-1, Annex
C).
3
.1.1
A
m
e
r
ica
n
ci
r
cui
t
s
fo
r
ballas
t
s
I
n t
hi
s context
i
t
i
s
i
mportant to note t
h
at t
h
e supp
ly
volta
g
e in America has a different frequency
(
60 Hz
)
.
A
s the inductive resistance o
f
the choke de
p
ends
on the
f
requenc
y
, in this case it is important to use a
desi
g
nated ballast
f
or the correspondin
g
f
requency. In
addition, both lamps and ballasts in the U
S
A are stan
-
dardized b
y
AN
S
I, the American National
S
tandards
I
nst
i
tute.
T
o operate t
h
e s
y
stems correct
ly
,
l
amps must
b
e operate
d
w
i
t
h
correspon
di
ng
b
a
ll
asts.
R
at
i
ngs
d
es-
i
g
nations are required by AN
S
I to be marked clearly on
all products, allowin
g
users to clearly identi
f
y system
a
g
reemen
t.
3.1.1.1 Autoleak trans
f
ormer or hi
g
h reactance auto
-
tr
a
n
sfo
rm
er
I
f
the supply volta
g
e is smaller than around twice the
lamp volta
g
e, as is the case, for example, in the U
S
A
or Japan, then the supply volta
g
e must
f
irst be stepped
u
p. A
g
ood way o
f
doin
g
this is use an autoleak trans-
f
ormer. Part o
f
the secondary windin
g
s act as lamp
choke.
O
n the one hand
,
this saves on material
,
and on
the other hand, a hi
g
her volta
g
e
(
open-circuit volta
g
e
)
is available to start the lamp. These t
y
pes o
f
ballasts
are typically more economical than a constant wattage
style ballasts at the expense o
f
watta
g
e re
g
ulation.
3.1.1.2
C
onstant watta
g
e ballast
A
constant watta
g
e
b
a
ll
ast suc
h
as t
h
ose w
id
e
l
y ava
il-
able in the
US
A consists of an autoleak transformer in
series with a capacitor. The advanta
g
e o
f
this circuit is
the reduced impact o
f
f
luctuations in the suppl
y
volt-
a
g
e and the possibility o
f
operatin
g
the lamp at supply
volta
g
es
(
110
/
120 V in the U
S
A, 100 V in Japan
)
that
lie within the ran
g
e o
f
the lamp volta
g
e
.
Fi
g
. 7: Autoleak trans
f
orme
r
C
... capac
i
tor
L
a ...
l
am
p
U
S
... supp
l
y vo
l
ta
ge
Tr ...
au
t
o
l
ea
k tr
a
n
sfo
rm
er
L
a
Tr
U
S
C
C
PF
C
... PF
C
capacito
r
L
a ...
l
am
p
U
S
... supply volta
ge
Tr ...
au
t
o
l
ea
k tr
a
n
sfo
rm
e
r
L
a
T
r
U
S
C
P
F
C
•
M
ax
i
mum perm
i
tte
d
supp
ly
vo
l
ta
g
e
d
ev
i
at
i
ons:
5
%
in the short-term, 3
%
in the lon
g
-term, use
ot
h
er tap on t
h
e c
h
o
k
e
if
necessar
y.
•
Maximum deviation of choke im
p
edance 2%.
•
T
he choke must be protected a
g
ainst overheatin
g
accordin
g
to the standard
(
thermal fuse
)
.
Fig. 8: Constant wattage ballas
t
1
0
3
.1.
2
V
ar
i
at
i
on
i
n supp
l
y vo
l
tage
f
or a
d
apte
d
i
n
duc
t
a
n
ce
S
ome countries have supply volta
g
es that permanently
deviate
f
rom 230V. When usin
g
correspondin
g
ly adapt
-
ed inductances, the following points must be taken
i
nto account
.
3.1.2.1
O
peration at suppl
y
volta
g
e hi
g
her than 230 V
w
i
t
h
a
d
a
p
te
d
c
h
o
k
e
i
m
p
e
d
ance
A
n increase in supply voltage shi
f
ts the maximum o
f
the choke characteristic curve
(P
L
over
U
L
/U
N
)
. In the
lamp volta
g
e ran
g
e of
OS
RAM lamps
(
approx. 100 V
)
,
t
h
e c
h
an
g
e
i
n
l
amp watta
g
e w
i
t
h
c
h
an
gi
n
g
l
amp vo
l
t
-
a
g
e
i
s steeper.
I
n a
ddi
t
i
on, t
h
e max
i
mum watta
g
e t
h
at
can
b
e ac
hi
eve
d
w
i
t
h
i
ncreas
i
ng
l
amp vo
l
tage
i
s
l
arger,
as s
h
own
i
n
Fig
. 9.
N
orma
ll
y, t
h
e
l
amp vo
l
ta
g
e
i
n-
creases with increasin
g
service life
(
see also chapter 6
“Lamp service life, a
g
in
g
and failure behavior”
).
A
ccordin
g
to equation Eq. 4.1, watta
g
e o
f
about 150 W
is achieved
f
or a 150 W choke with a lamp volta
g
e o
f
100
V
.
Th
e max
i
mum t
h
e
l
amp watta
g
e can
i
ncrease
to
f
or a lamp volta
g
e o
f
150 V is 175 W. The hi
g
he
r
achievable watta
g
e can reduce the service li
f
e and
possibl
y
cause an increase o
f
undesirable e
ff
ects at
the end of the service life (e.
g
. lamp explosion)
.
OS
RAM lamps are
g
enerally desi
g
ned to operate at
230
V
supp
l
y vo
l
ta
g
e an
d
un
d
er
g
o correspon
di
n
g
ser-
vice li
f
e testin
g
. There are, however, also systems at
400 V, e.g.
f
or some discharge lamps > 1000 W. Fo
r
these lamps, the
f
ollowin
g
explanations apply in the
same way. The use o
f
hi
g
h intensity dischar
g
e lamps is
t
h
eoret
i
ca
ll
y a
l
so poss
ibl
e at 277
V
operat
i
n
g
vo
l
ta
g
e
w
i
t
h
a
d
apte
d
i
mpe
d
ance an
d
ig
n
i
t
i
on
d
ev
i
ces, a
l
t
h
ou
gh
suc
h
o
p
erat
i
on
i
s assoc
i
ate
d
w
i
t
h
cons
id
era
bl
e
di
sa
d-
vantages
.
a
)
An increase in ne
g
ative effects must be expected
at the end o
f
the service li
f
e, because watta
g
e
r
i
ses c
l
ear
l
y a
b
ove t
h
e nom
i
na
l
watta
g
e w
h
en
lamp volta
g
e increases on account o
f
the shi
f
ted
choke
cha
r
ac
t
e
r
is
t
ic
cu
rv
e
.
The
i
n
c
r
eased
w
a
tt-
a
g
e input
f
or lamps with already a
g
ed arc tube
wa
ll
can cause
i
ncrease
d
l
amp exp
l
os
i
on rates,
f
or exam
p
le.
Op
eration in overload conditions
will probably cause accelerated a
g
in
g.
b
)
The stee
p
er characteristic
P
L
(U
L
)
in the ran
g
e of
t
h
e norma
l
l
amp vo
l
ta
g
e causes a
high
er sprea
d
o
f
the watta
g
e and there
f
ore o
f
the photometric
d
ata, e.
g
. perce
i
ve
d
co
l
our var
i
at
i
on
.
W
e there
f
ore discoura
g
e operatin
g
the lamps at 277
V
supply volta
g
e.
O
ur lamps have been developed and
under
g
one service li
f
e testin
g
at 230 V supply volta
g
e,
so that we cannot assume an
y
warrant
y
f
or the service
life behavior and photometric data for any deviatin
g
o
p
erat
i
on
.
3.1.2.2 Operation at supply voltage less than 230 V
w
i
t
h
a
d
apte
d
c
h
o
k
e
i
mpe
d
ance
S
upply volta
g
es of less than 230 V
shif
t t
he
m
a
x
i
m
u
m
o
f the choke curve
(P
L
over
U
L
/U
S
)
.
Op
eration at 200 V
supply volta
g
e
f
or example is more
f
avorable than at
230 V with re
g
ard to the chan
g
e in lamp watta
g
e with
l
amp vo
l
ta
g
e.
Th
e
P
L
(U
L
)
curve runs fl atter in the normal
ran
g
e o
f
lamp volta
g
e. For lamp volta
g
es exceedin
g
130 V Watta
g
e
f
alls a
g
ain
.
T
here is a major drawback that with lower suppl
y
volt
-
ag
e, there is also less volta
g
e available
f
or re-i
g
nition
af
ter the current has passed zero crossin
g
. I
f
the mo-
m
entary supp
l
y vo
l
ta
g
e
i
s
l
ower t
h
an t
h
e re-
ig
n
i
t
i
on
volta
g
e, the lamp
g
oes o
ff
. Normally, the lamp volta
g
e
a
nd also the re-i
g
nition peak increase with increasin
g
service life
(
see also chapter 6, “Lamp service life, a
g
-
in
g
and failure behavior”). That means that a reduction
in supply volta
g
e causes a shorter service li
f
e in many
l
am
p
s
.
Fig
. 9:
L
amp current
I
L
,
l
amp watta
g
e
P
L
o
v
e
r t
he
r
a
t
io
o
f
lamp volta
g
e to suppl
y
volta
g
e U
L
/U
S
f
or
U
S
=277
V
Fig
. 10:
L
amp current
I
L
,
l
amp watta
g
e
P
L
o
v
e
r t
he
r
a
t
io
o
f
lamp volta
g
e to suppl
y
volta
g
e U
L
/U
S
at
U
N
=2
00
V
200
180
160
140
120
100
80
60
40
20
0
Lamp power P
in W
L
Lamp current I in A
U /U
L
S
3
2,5
2
1,5
1
0,5
0
0
0,5
1
L
U /U
L
S
Lamp current I
in
A
3
2,5
2
1,5
1
0,5
0
Lamp power P
in W
L
0
0,5
1
200
180
160
140
120
100
80
60
40
20
0
L
11
3
.1.
3
I
n
fl
uence o
f
d
ev
i
at
i
ons
i
n supp
l
y vo
l
ta
g
e
Wh
en operat
i
n
g
meta
l
h
a
lid
e
l
amps on a c
h
o
k
e, t
h
e
l
amp parameters c
h
ange
d
epen
di
ng on t
h
e supp
l
y
vo
l
ta
g
e.
T
o
li
m
i
t t
h
e assoc
i
ate
d
var
i
at
i
on
i
n
l
amp p
h
o
-
tometrics, a maximum deviation in supply volta
g
e o
f
5
%
f
rom the nominal values
f
or the supply volta
g
e is
permitted in the short term, or maximum 3
%
in the
lon
g
term. For deviations over a lon
g
er period o
f
time,
su
i
ta
bl
e
b
a
ll
ast tap must
b
e se
l
ecte
d
.
A
s c
h
o
k
e
i
mpe
d
-
ance also in
f
luences the lam
p
p
arameters via the cor
-
respon
di
n
gl
y a
dj
uste
d
l
amp current, t
hi
s
i
s a
ll
owe
d
to
deviate
f
rom the nominal values b
y
maximum 2
%.
R
emote mount
i
n
g
can a
l
so cause not
i
cea
bl
e
d
e
-
creases in volta
g
e
(
see also chapter 7.4 “Leads to
luminaires”
).
L
on
g
term re
d
uct
i
ons
i
n
l
amp watta
g
e cause t
h
e
l
um
i
-
n
ous
f
lux to decrease
,
with a shorter service li
f
e and
a deviation in colour
f
rom the nominal values
,
as also
ex
pl
a
i
ne
d
i
n c
h
a
p
ter 5:
“W
atta
g
e re
d
uct
i
on
i
n
high
i
ntensit
y
dischar
g
e lamps”
.
I
f
the supply volta
g
e is too hi
g
h, the arc tube is op-
erate
d
at too
h
ot a temperature, caus
i
n
g
i
ncrease
d
blackenin
g
and a shorter service li
f
e
.
3.1.4
C
a
p
acitor for
p
ower factor correction
The capacitor
f
or power
f
actor correction is necessar
y
to
c
orrect the power
f
actor o
f
the system when operatin
g
di
sc
h
ar
g
e
l
amps at e
l
ectroma
g
net
i
c
b
a
ll
asts.
I
n
d
uct
i
ve
l
y
stabilized dischar
g
e lamps achieve power
f
actors o
f
only
a
bout 0.5 because o
f
the de
p
hased current
fl
ow. The
p
ower
f
actor o
f
a load is de
fi
ned as the ratio o
f
e
ff
ective
power to the apparent power actuall
y
withdrawn
f
rom
the
g
rid
(
kW to kvar
)
and is referred to as cos
ϕ
.
The
apparent power comprises the e
ff
ective power used b
y
t
h
e consumers to create e.g.
h
eat or mec
h
an
i
ca
l
energy
an
d
t
h
e
idl
e power t
h
at
i
s use
d
to
d
eve
l
op ma
g
net
i
c or
electric
fi
elds o
f
inductivit
y
and capacit
y
. However the
latter
fl
ows back into the
g
rid a
f
ter a hal
f
cycle len
g
th,
i
.e.
i
t
i
s not actua
lly
“
use
d”
.
Th
e c
l
oser cos
ϕ
i
s to one
,
the smaller is the share o
f
wattless
p
ower withdrawn
f
rom the
g
rid. A hi
g
her share o
f
wattless power results in
a hi
g
her
fl
ow in current
f
or which the supply lines have to
be rated.
S
imilarl
y
, power dissipation in the suppl
y
lines
i
ncreases
i
n a square pro
g
ress
i
on w
i
t
h
t
h
e current.
I
n
or
d
er to ac
hi
eve t
h
e va
l
ues
d
eman
d
e
d
by
t
h
e ut
ili
t
y
com
-
panies o
f
more than 0.85, a
g
rid parallel capacitor must
b
e se
l
ecte
d
accor
di
n
g
to t
h
e
l
amp or c
h
o
k
e current to
approximately correct the shi
f
t in phase. By includin
g
an
exactl
y
calculated capacitor, the inductive wattless load
required b
y
an electric consumer can be o
ff
set with a
ca
p
ac
i
t
i
ve watt
l
ess
l
oa
d
.
I
t
i
s t
h
us
p
oss
ibl
e to re
d
uce t
h
e
wattless power withdrawn
f
rom the
g
rid; this is called the
p
ower
f
actor correction or wattless
p
ower com
p
ensation
.
Th
e ca
p
ac
i
tors are
diff
erent
i
ate
d
as
f
o
ll
ows,
d
ependin
g
on the arran
g
ement and form of use:
INDIVIDUAL OR FIXED COMPENSATION
,
where the in-
d
uct
i
ve watt
l
ess power
i
s correcte
d
di
rect
ly
w
h
ere
i
t occurs,
relievin
g
the strain on the leads (typical for individual con-
sumers usua
ll
y wor
ki
n
g
i
n cont
i
nuous mo
d
e w
i
t
h
constant
or re
l
at
i
ve
l
y
l
ar
g
e watta
g
e –
di
sc
h
ar
g
e
l
amps, async
h
ro-
n
ous motors, transformers, weldin
g
equipment, etc.
)
Fi
g
. 11: Lamp parameters of a t
y
pical
OS
RAM H
Q
I
®
l
amp over supp
ly
vo
l
ta
g
e
Percentage of the nominal value
Percentage of the nominal supply voltage
UL in %
IL in %
PL in %
FL in %
UL
...
L
amp vo
l
ta
g
e
I
L ... Lam
p
current
P
L ... Lamp powe
r
F
L ... L
u
min
ous
fl
u
x
Fi
g
. 12: Lamp parameters of a t
y
pical
OS
RAM H
C
I
®
l
amp over supp
ly
vo
l
ta
ge
Percentage of the nominal value
Percentage of the nominal supply voltage
UL in %
IL in %
PL in %
FL in %
UL ... Lamp volta
ge
IL ... Lam
p
curren
t
PL ... Lam
p
p
owe
r
FL ... L
u
min
ous
fl
ux
12
The parallel capacitor has no in
f
luence on lamp
b
e
h
av
i
or
.
G
R
O
UP
CO
MPEN
S
ATI
O
N, where one
j
oint fixed ca-
pac
i
tor
i
s a
ll
ocate
d
to s
i
mu
l
taneous
l
y wor
ki
n
g
i
n
d
uc
-
tive consumers, similar to individual correction
(
motors
located close to
g
ether, dischar
g
e lamps). Here a
g
ain
t
h
e stra
i
n on t
h
e
l
ea
d
s
i
s re
li
eve
d
,
b
ut on
ly
up to t
h
e
p
oint o
f
distribution to the individual consumers. Un
-
der un
f
avorable conditions
,
resonance can be caused
i
n two-p
h
ase
g
r
id
s
.
C
ENTRAL
CO
MPEN
S
ATI
O
N
,
where a number of ca
-
p
ac
i
tors are connecte
d
to a ma
i
n or su
b
-
di
str
ib
ut
i
on
stat
i
on.
Thi
s
i
s t
h
e norma
l
proce
d
ure
i
n
l
ar
g
e e
l
ectr
i
ca
l
systems w
i
t
h
c
h
an
gi
n
g
l
oa
d
.
H
ere t
h
e capac
i
tors are
contro
ll
e
d
by
an e
l
ectron
i
c contro
ll
er w
hi
c
h
constant
ly
analyzes the demand
f
or wattless power in the
g
rid.
This controller switches the capacitors on or o
ff
to cor
-
rect the current wattless
p
ower o
f
the total load and
t
h
us re
d
uce overa
ll
d
eman
d
i
n t
h
e
g
r
id.
C
a
p
acitor for
p
ower factor correction values are
stated
f
or ever
y
lamp t
y
pe in the Technical In
f
ormation
and can also be calculated usin
g
the
f
ollowin
g
equa-
t
io
n
.
C
PF
C
in F
C
apacitance of the capacitor for power
fac
t
o
r
co
rr
ec
ti
on
U
S
i
n
V
R
ate
d
supp
l
y vo
l
ta
ge
f
S
in Hz
S
uppl
y
frequenc
y
I
L
i
n
A
L
amp rate
d
curren
t
P
W
in W Total active power
(
lamp rated wattage plus
choke loss watta
g
e
)
ϕ
K
Tolerable or desirable
p
hase di
ff
erence be
-
tween the
f
undamental waves o
f
the suppl
y
vo
l
ta
g
e an
d
t
h
e supp
l
y current
.
But this onl
y
corrects the power
f
actor
f
or the
f
unda
-
m
ental wave. Phase di
ff
erence remains
f
or distortion
,
i
.e. t
h
e
h
armon
i
c waves,
b
etween current an
d
vo
l
ta
g
e.
For this reason, the overall power
f
actor can also onl
y
reac
h
va
l
ues
b
etween 0.95 an
d
0.98
i
n
p
ract
i
ce
.
A
hi
g
her level o
f
harmonic waves can cause resonance
e
ff
ects and destro
y
the lamp. A power
f
actor close to 1
is
t
o
be
a
v
oided
as
t
his
ca
n
cause
r
eso
n
a
n
ce
be
tw
ee
n
t
h
e c
h
o
k
e an
d
correct
i
on capac
i
tor
.
W
hile a dischar
g
e lamp is startin
g
up, the power
f
actor
u
nder
g
oes si
g
ni
f
icant chan
g
es in value. A
f
ter i
g
nition,
the lamp volta
g
e is still very low with current hi
g
her
than in stead
y
state. This is wh
y
the power
f
actor in
this state is still low (inductive). While lamp volta
g
e
increases and the lamp current
f
alls, the power
f
acto
r
in
c
r
eases
t
o
it
s
n
o
min
a
l v
a
l
ue
of
0
.
85
–
0
.
9.
A
s dischar
g
e lamps a
g
e, it is normal
f
or lamp volta
g
e to
increase, causin
g
the lamp current to
f
all accordin
g
to
the ballast curve. Because the capacitor
f
or power
f
actor
correction is rated
f
or a s
p
eci
fi
c lam
p
and choke current,
the power
f
actor varies accordin
g
to lamp current. For an
extreme
l
y
hi
g
h
l
amp vo
l
tage, t
h
e c
h
o
k
e current
i
s so
l
ow
t
h
at ca
p
ac
i
t
i
ve current excee
d
s t
h
e
i
n
d
uct
i
ve current an
d
t
h
e comp
l
ete c
i
rcu
i
t
b
ecomes capac
i
t
i
ve
.
Under certain conditions, audio
f
requenc
y
central con-
tro
l
systems
h
ave to
b
e cons
id
ere
d
d
ur
i
n
g
i
nsta
ll
at
i
on.
In these cases, suitable audio
f
requenc
y
attenuation
chokes are to be provided. This kind o
f
s
y
stem is still
sometimes used for day
/
ni
g
ht circuits in street li
g
htin
g
,
although directional radio systems are
f
inding increas-
i
n
g
use
h
ere
.
3.2 Electronic control
g
ear
(
E
CG)
To
g
ether with conventional ballasts, the use o
f
elec
-
tron
i
c
b
a
ll
asts
h
as meanw
hil
e
b
ecome w
id
e
ly
accepte
d
practice, particularly
f
or interior li
g
htin
g
.
Electronic ballasts o
ff
er clear advanta
g
es compared
to convent
i
ona
l
b
a
ll
asts.
Th
e ma
i
n a
d
vanta
g
es
i
nc
l
u
d
e
in particular simplified handlin
g
(
e.
g
. li
g
hter ballasts
)
,
l
ower ener
g
y consumpt
i
on, a pos
i
t
i
ve
i
mpact on
l
amp
service li
f
e and li
g
ht quality, and, last but not least,
controlled and reliable shutdown o
f
lamps at the end
o
f
the service li
f
e
.
Basicall
y
, most o
f
the technical in
f
ormation provided in
t
hi
s manua
l
a
ppli
es to
b
ot
h
convent
i
ona
l
b
a
ll
asts an
d
electronic ballasts. This re
f
ers
f
or example to wirin
g
requirements, wattage-reduced operation o
f
MH lamps
or instructions
f
or luminaire desi
g
n
.
But in addition
,
there are also considerable di
ff
erences
b
etween operat
i
on on an e
l
ectron
i
c or ma
g
net
i
c
b
a
ll
ast.
The
f
ollowin
g
section brie
f
ly explains the main di
ff
er
-
e
n
ces
a
n
d
th
e
ir
effec
t
s.
3.2.1 Structure and functionin
g
of an electronic
ballas
t
Electronic ballasts mainl
y
consist o
f
units with rect-
a
n
g
u
l
ar current an
d
vo
l
ta
g
e.
I
n pr
i
nc
i
p
l
e,
i
t
i
s a
l
so
possible to operate the lamps with hi
g
h-
f
requency
sinusoidal current similar to the
f
luorescent lam
p
. In
a
n
y
case,
i
t
i
s
i
mportant to ensure t
h
at no acoust
i
c
resonances occur as t
h
ese ma
y
resu
l
t
i
n arc
i
nsta
bili
t
y
(
lam
p
flicker
)
and in severe cases, lam
p
ru
p
ture
.
3.2.2
S
ervice life and tem
p
erature
T
here is a si
g
ni
f
icant di
ff
erence between conventional
a
n
d
e
l
ectron
i
c
b
a
ll
asts part
i
cu
l
ar
l
y w
i
t
h
re
g
ar
d
to t
h
e
se
rvi
ce
li
fe
a
n
d
th
e
rm
a
l
be
h
a
vi
o
r
of
th
e
u
nit
s.
()
⎟
⎠
⎞
⎜
⎝
⎛
×−−
××
×××
=
KWWL
S
SS
PP
I
U
Uf
C
ϕ
π
tan
2
1
22
2
2
PFC
E
q. 4.
3
1
3
U
S
ECG
Luminaire
Lamp
Fi
g
. 13:
S
implified circuit dia
g
ram showin
g
the elec
-
tronic operation o
f
hi
g
h intensit
y
dischar
g
e lamp
s
Voltage in V
Current in A
Time in ms
Fi
g
. 14:
C
urrent and volta
g
e of a metal halide lamp
operate
d
on a rectangu
l
ar e
l
ectron
i
c
b
a
ll
ast
For a conventional ballast, it can be
p
resumed that the
service li
f
e is de
f
ined b
y
the choke temperature
t
w
.A
10 °
C
increase in the
t
w
temperature means t
h
at t
h
e
se
rvi
ce
li
fe
i
s
h
a
lv
ed.
In electronic ballasts
,
these circumstances are
f
a
r
mo
r
e
complicated. The mortalit
y
rate o
f
individual com
-
ponen
t
s,
t
h
e c
i
rcu
i
t
d
es
ig
n an
d
a
b
ove a
ll
t
h
e e
l
ectron
i
c
l
oa
d
an
d
t
h
e temperatures at w
hi
c
h
t
h
e un
i
ts are oper
-
a
t
ed
h
a
v
e
a
co
n
s
i
de
r
ab
l
e
in
f
l
ue
n
ce
o
n th
e
se
rvi
ce
li
fe
beha
v
io
r
.
This is wh
y
the nominal service li
f
e o
f
electronic
ballasts is stated in combination with a
f
ailure prob
-
abilit
y
. For example, all units in the product
f
amil
y
P
O
WERTR
O
NI
C
®
PTi h
a
v
e
a
n
o
min
a
l
se
rvi
ce
li
fe
of
40,000 hours with
f
ailure probabilit
y
o
f
maximum
10
%
when o
p
erated at the maximum
p
ermissible
t
em
p
era
t
ures
.
Th
e
se
rvi
ce
li
fe
of
e
l
ec
tr
o
ni
c
ba
ll
as
t
s
i
s
in
f
l
ue
n
ced
directl
y
b
y
the temperature at which the units are op
-
erated. This is wh
y
2 temperature values are de
f
ined
t
o
desc
r
ibe
t
he
t
he
rm
al
beha
v
io
r.
The
a
m
bie
nt t
e
m
-
pera
t
ure
t
a
d
escr
ib
es t
h
e temperature
i
mme
di
ate
ly
surroun
di
n
g
t
h
e un
i
t an
d
t
h
us preva
ili
n
g
aroun
d
t
h
e
e
l
ectron
i
c com
p
onents.
T
o
b
e c
l
ear, t
hi
s
i
s not t
h
e
room tem
p
erature or the ambient tem
p
erature of the
lu
m
i
n
ai
r
e.
When an electronic ballast is
f
itted in a luminaire
,
the
rea
l
am
bi
ent tem
p
erature
t
a
o
f
the ballast can onl
y
be
measured with
g
reat difficulty and at
g
reat effort. This
i
s w
hy
a secon
d
temperature
h
as
b
een st
i
pu
l
ate
d
: t
h
e
t
c
temperature.
B
as
i
ca
ll
y t
hi
s
i
s t
h
e cas
i
n
g
tempera
-
ture w
hi
c
h
can
b
e measure
d
by
a t
h
ermocoup
l
e at a
set po
i
nt – t
h
e t
c
point – and is de
f
ined as maximum
permissible temperature at which sa
f
e operation o
f
the
el
ectron
i
c
b
a
ll
ast
i
s st
ill
g
uarantee
d
.
I
n a
ddi
t
i
on, t
h
e
t
c
tem
p
erature is set in relation to the ballast service li
f
e.
T
hat means that the measured
t
c
tem
p
erature
p
ermits
ver
y
prec
i
se conc
l
us
i
ons as to t
h
e ant
i
c
i
pate
d
serv
i
ce
li
fe
of
th
e
e
l
ec
tr
o
ni
c
ba
ll
as
t
.
OS
RAM’s HID electronic ballast for example principall
y
r
eac
h
es
it
s
fu
ll n
o
min
a
l
se
rvi
ce
li
fe
a
t th
e
m
a
xim
u
m
p
erm
i
tte
d
t
c
tem
p
erature.
I
n
p
ract
i
ce, t
hi
s means
t
h
at an
y
temperature
l
eve
l
s
b
e
l
ow t
h
e
t
c
t
empera
t
ure
always prolon
g
the e
ff
ective service li
f
e. As a rule o
f
thumb, it can be presumed that a temperature 10 °
C
b
e
l
ow t
h
e
p
r
i
nte
d
max
i
mum t
c
tem
p
erature w
ill
d
ou
bl
e
th
e
se
rvi
ce
li
fe
of
th
e
e
l
ec
tr
o
ni
c
ba
ll
as
t
.
H
owever,
i
t
i
s not a
d
v
i
sa
bl
e to use on
ly
t
h
e a
b
so
l
ute
m
a
x
i
m
u
m t
ole
r
able
t
c
value
f
or conclusions re
g
ardin
g
the qualit
y
and service li
f
e o
f
an electronic ballast. This
is because on the one hand, the
p
osition and there
f
ore
indirectl
y
also the value o
f
the
t
c
point can be
f
reel
y
defined b
y
ever
y
electronic ballast manufacturer.
O
n
the other hand, the rule o
f
statin
g
the nominal service
li
f
e at the maximum
p
ermitted
t
c
tem
p
erature
h
as not
yet
b
ecome esta
bli
s
h
e
d
t
h
rou
gh
out t
h
e e
l
ectron
i
c
ballast industr
y
. In practice this means that man
y
electronic ballasts onl
y
achieve approx. 50
%
o
f
their
n
o
min
a
l
se
rvi
ce
li
fe
a
t m
a
xim
u
m t
c
t
empera
t
ure
.
3
.
2
.
3
Ad
vanta
g
es o
f
operat
i
on w
i
t
h
e
l
ectron
i
c
ballast P
O
WERTR
O
NI
C
®
PTi
T
he
f
ollowin
g
table provides an overview o
f
the advan-
ta
g
es o
f
operatin
g
lamps with the electronic ballast
.
Th
e correspon
di
n
g
va
l
ues an
d
statements are
b
ase
d
on tests and ex
p
erience with P
O
WERTR
O
NI
C
®
PTi
ballasts, so that the
y
cannot necessaril
y
be trans
f
erred
1:1 t
o
ba
ll
as
t
s
of
o
th
e
r m
a
k
es.
I
n compar
i
n
g
t
h
e convent
i
ona
l
an
d
t
h
e e
l
ectron
i
c
ballast, the
p
er
f
ormance o
f
the conventional ballast
constitutes the reference parameter and is
g
iven a
v
a
l
ue
of
1
00
. Thi
s
i
s
a
l
so
based
o
n th
e
fac
t th
a
t th
e
lam
p
p
arameters are de
f
ined with the re
f
erence
co
nv
e
nt
io
n
al
ballas
t
.
For more details,
p
lease refer to the P
O
WERTR
O
NI
C
®
T
echnical
G
uide – Electronic control
g
ears for metal
h
a
lid
e
l
amps
.
Nominal service life
(
B10
)
: max. 10% of the
e
l
ectron
i
c
b
a
ll
asts
h
ave
f
a
il
e
d
A
se
r
ious
e
v
alua
t
io
n
of
t
he
elec
tr
o
n
ic
ballas
t
serv
i
ce
lif
e
i
s on
ly
poss
ibl
e
by
compar
i
n
g
t
h
e
e
l
ectron
i
c
b
a
ll
ast am
bi
ent tem
p
erature t
a
w
ith
t
h
e correspon
di
n
g
serv
i
ce
lif
e.
C
omparison of the service life usin
g
onl
y
the t
c
tem
p
erature
i
s not a
pp
ro
p
r
i
ate
.
14
The main advanta
g
es o
f
electronic ballasts are
described in
g
reater detail in the
f
ollowin
g
section
.
3.2.3.1
R
e
d
uc
i
n
g
ener
gy
consumpt
i
on
C
ompared to conventional ballasts, electronic ballasts
can cons
id
era
bl
y re
d
uce ener
g
y consumpt
i
on over t
h
e
service li
f
e. The ener
g
y savin
g
s result
f
rom two
f
actors
:
1
)
Unit
p
ower dissi
p
ation:
In conventional ballasts a lar
g
e amount o
f
ener
g
y
is lost in dissi
p
ated heat on account o
f
the
d
es
ig
n.
B
y contrast, e
l
ectron
i
c
b
a
ll
asts
h
ave a
l
ow-
l
oss
d
es
ig
n w
i
t
h
top qua
li
ty components,
reducin
g
dissipation to less than 10
%
o
f
the
nom
i
na
l
p
ower
.
2
)
Increase in watta
g
e over service life
:
The system watta
g
e with conventional ballasts
fl
uctuates si
g
ni
fi
cantly over the service li
f
e o
f
the
lamp. This results
f
rom the chan
g
e in lamp volt
-
a
g
e, which can increase by up to 30
%
throu
g
hout
the service life
(
see also chapter 3.1.2
)
, resultin
g
in considerable
fl
uctuations in lamp watta
g
e.
B
y
contrast, electronic ballasts operate the
l
amps a
l
ways w
i
t
h
constant watta
g
e t
h
rou
gh
out
th
e
e
ntir
e
se
rvi
ce
li
fe
. Th
e
m
a
xim
a
l t
o
l
e
r
a
t
ed
f
luctuation is 3
%
. This means
f
or example that
f
or a 70 W ceramic arc tube lam
p
, the electronic
b
a
ll
ast constant
ly
prov
id
es t
h
e
l
amp w
i
t
h
t
h
e
r
a
t
ed
7
3
W.
3.2.3.2 Lam
p
service li
f
e and cut-out at the end o
f
the
se
rvi
ce
li
fe
A
detailed descri
p
tion o
f
the lam
p
service li
f
e and
f
ail-
u
re behavior usin
g
conventional ballasts can be
f
ound
i
n c
h
a
p
ter 6
.
Electronic ballast o
p
eration also o
ff
ers considerable
advanta
g
es in terms of lamp service life and cut-out
be
h
a
vi
o
r
a
t th
e
e
n
d
of
th
e
se
rvi
ce
li
fe.
C
omprehensive laborator
y
tests and extensive practi-
ca
l
ex
p
er
i
ence s
h
ow t
h
at o
p
erat
i
on on e
l
ectron
i
c
b
a
l-
lasts has a si
g
ni
f
icantly positive in
f
luence on the lamp
service li
f
e. Precise but
g
entle lamp i
g
nition, a more
sta
bl
e t
h
erma
l
b
a
l
ance t
h
an
k
s to constant watta
g
e
M
a
g
net
i
c
b
a
ll
ast Electronic ballast P
O
WERTR
O
NI
C
®
E
ner
g
y consumpt
i
o
n
1
00
10 to 15
%
savin
g
s over the service
li
fe
L
amp serv
i
ce
life
1
00
Up to 30
%
lon
g
er dependin
g
on
lamp t
y
pe and kind o
f
us
e
L
am
p
start-u
p
D
epen
d
s on t
y
pe: usua
lly
approx.
60 to 90 sec. to reach 90
%
o
f
the
luminous
f
lux leve
l
U
p
to 50
%
f
aste
r
Colour stabilit
y
Colour variation
p
ossibl
e
Clearly reduced scatterin
g
; initial and
o
v
e
r
se
rvi
ce
li
fe
C
ut-out at end of lam
p
service
life
N
ot ava
il
a
bl
e or on
ly
s
i
mp
l
e
cu
t-
ou
t m
echa
n
is
m
s
P
ermanent
p
arameter contro
l
,
i
nte
llig
ent cut-out mec
h
an
i
sms
I
gn
i
t
i
on cut-out
O
nly with timer ignition unit
s
I
gn
i
t
i
on t
i
me
li
m
i
te
d
to 18 m
in
Ligh
t
fli
c
k
e
r
V
i
s
i
b
l
e
f
li
c
k
er
Flicker-
f
ree thanks to 165 Hz o
p
eratio
n
C
onsistent wattag
e
I
ncrease
i
n watta
g
e over serv
i
ce
li
f
e, also de
p
endent on
f
luctua
-
t
i
ons
i
n temperature an
d
supp
ly
vo
l
ta
g
e, an
d
on
l
ea
d
l
en
g
t
h
+
3
%
over the entire service li
f
e
,
re
g
ardless o
f
f
luctuations in
temperature an
d
supp
l
y vo
l
ta
g
e
o
r
l
ea
d
l
en
g
t
h
Handlin
g
3 com
p
onents, com
pli
cate
d
w
i
r
i
n
g
1 un
i
t, s
i
mp
l
e w
i
r
i
n
g
S
ize and wei
g
h
t
H
eavy, severa
l
components,
l
ar
g
e
i
n
so
m
e
cases
Ligh
t an
d
compac
t
Power factor correction
(
PF
C)
0.5 – 0.95, cons
id
era
bl
e a
gi
n
g
f
l
uc
t
ua
ti
o
n
s
>
0
.
95
N
o
i
se
d
eve
l
o
p
men
t
C
learly audible hummin
g
possibl
e
Al
m
os
t n
oiseless
Bidi
rect
i
ona
l
d
ata exc
h
an
g
e
Not
p
ossible
G
enerall
y
possible
1
5
supp
ly
an
d
, a
b
ove a
ll
, a c
l
ear
ly
re
d
uce
d
ten
d
enc
y
to
g
o out
b
y avo
idi
n
g
re-
ig
n
i
t
i
on pea
k
s a
ll
l
en
g
t
h
en t
h
e
lamp economic li
f
e
f
or ceramic arc tube lamps b
y
up
to 30
%
on avera
g
e
.
The electronic ballast also shows its strengths at the
end o
f
the lamp service li
f
e. The i
g
nition time limit
ensures t
h
at o
ld
l
amps, w
h
ere sta
bl
e operat
i
on
i
s no
l
on
g
er poss
ibl
e, are not su
bj
ect to en
dl
ess
ig
n
i
t
i
on
attempts. A
f
ter max. 18 minutes and precisel
y
de
f
ined
i
g
nition intervals, the P
O
WERTR
O
NI
C
®
E
CG
cuts out
automatically. I
f
a lamp goes out 3 times, the electronic
ballast also cuts out. This avoids inter
f
erin
g
,
f
lickerin
g
li
g
ht, prevents EM
C
load on the cables and also an
e
x
cess
iv
e
l
oad
o
n th
e
e
l
ec
tr
o
ni
c
ba
ll
as
t it
se
l
f.
Permanent monitorin
g
o
f
parameters such as lamp
vo
l
ta
g
e or
l
amp current
b
y t
h
e
i
nte
g
rate
d
m
i
cro-con
-
troller and ali
g
nment with pre-de
f
ined nominal values
also makes it possible to turn lamps o
ff
well be
f
ore
the
y
reach critical or unde
f
ined conditions which o
f
ten
can
h
ar
dl
y
b
e mana
g
e
d.
3.2.3.3
Ligh
t qua
li
t
y
,
ligh
t co
l
our,
d
rop
i
n
ligh
t output,
s
tart-u
p
HID lamps with electronic ballasts o
ff
er considerabl
y
improved colour qualit
y
, both when initiall
y
installed
and throu
g
hout the service li
f
e
.
Th
e constant watta
g
e supp
li
e
d
to t
h
e
l
amp
b
y t
h
e
electronic ballast can com
p
ensate
f
or di
ff
erences in
light quality resulting
f
or example
f
rom production tol-
erances or di
ff
erin
g
a
g
in
g
states. The result is visibly
more even li
g
ht colour and a more uni
f
orm chromatic
-
i
t
y
coor
di
nate
.
S
imilarly, supply volta
g
e fluctuations or the len
g
th of
the power leads are no longer relevant when using an
e
l
ectron
i
c
b
a
ll
ast, as t
h
e constant watta
g
e supp
l
y to
the lamp means these have no e
ff
ect
.
L
am
p
e
l
ectro
d
es coo
l
d
own to a
l
esser extent w
i
t
h
the rectan
g
ular electronic ballast thanks to the steep
e
l
ectr
i
ca
l
trans
i
t
i
ons t
h
rou
gh
t
h
e zero cross
i
n
g
.
L
ess
coolin
g
down results in reduced sputter e
ff
ects o
f
the
e
l
ectro
d
es, w
hi
c
h
i
n turn means
l
ess
b
u
lb
bl
ac
k
en
i
n
g
.
Th
e more constant, an
d
on avera
g
e s
ligh
t
l
y
high
er,
lam
p
p
lasma tem
p
erature also
p
roduces 3
%
to 5
%
more luminous e
ff
icac
y
, which also has a positive in
f
lu
-
e
n
ce
in l
u
min
ous
f
l
u
x
be
h
a
vi
o
r in
add
iti
o
n t
o
r
educed
blackenin
g
e
ff
ects
.
Electronic ballasts also have a much
f
aster start-u
p
behavior than ma
g
netic ballasts. Fi
g
. 24 in chapter
4.7
f
or example clearl
y
shows that a double-ended
quartz
l
amp operat
i
n
g
w
i
t
h
an e
l
ectron
i
c
b
a
ll
ast a
l-
read
y
produces more than 90
%
o
f
its max. luminous
f
lux a
f
ter a
pp
rox. 40 seconds. The same luminous
f
lux
l
e
v
e
l with
a
co
nv
e
nti
o
n
a
l
ba
ll
as
t t
a
k
es
a
t l
eas
t 2
5
t
o
30
seconds lon
g
er. This at least 50
%
f
aster start-up at
t
h
e e
l
ectron
i
c
b
a
ll
ast
i
s
d
ue to t
h
e
high
er start-up
current o
f
the electronic ballast, producing a higher
watta
g
e input into the lamp which there
f
ore heats up
m
ore qu
i
c
kly.
3.2.3.4
S
ize, wei
g
ht and handlin
g
El
ectron
i
c
b
a
ll
asts com
bi
ne
ig
n
i
t
i
on component, com-
pensat
i
on component an
d
c
h
o
k
e
i
n one un
i
t.
Thi
s
3-
i
n-1 com
bi
nat
i
on c
l
ear
ly
re
d
uces t
h
e
i
nsta
ll
at
i
on
workload
,
the risk o
f
installation errors and the need
to replace individual
f
ault
y
units. Multi-lamp electronic
ballasts
(
e.g. 2x35 W or 2x70 W
)
duplicate these ad
-
vanta
g
es
b
ecause to connect to 2
l
um
i
nares, on
l
y one
power
l
ea
d
i
s requ
i
re
d.
El
ectron
i
c
b
a
ll
asts are a
l
so
ligh
twe
igh
t.
Th
ey we
igh
50
%
to 60
%
less than ma
g
netic ballasts, which o
f
course o
ff
ers direct advanta
g
es in terms o
f
luminaire
d
es
ig
n: t
h
ey can
b
e s
l
ee
k
er
i
n structure; a w
id
er ran
g
e
o
f
materials can be used, and a li
g
hter load can be
placed on the
f
astenin
g
components
.
3
.2.
3
.
5
Bi
d
ir
ec
ti
o
n
a
l
da
t
a
tr
a
n
sfe
r
Intelli
g
ent electronic units will in the
f
uture o
ff
er com-
pletely new possibilities o
f
controllin
g
and monitorin
g
li
g
htin
g
systems, thanks to bidirectional data trans
f
er.
Features such as queryin
g
the lamp or ballast status,
inte
g
ration in Buildin
g
Mana
g
ement
S
ystems
(
BM
S)
and central or local actuation and mana
g
ement o
f
ligh
t
i
n
g
so
l
ut
i
ons w
ill
not on
l
y
b
r
i
n
g
a c
l
ear
l
y expan
d
e
d
ran
g
e o
f
f
unctions but also optimize maintenance and
re
p
air work. In the medium term, it is
q
uite conceivable
to see
d
eve
l
o
p
ments
h
ere s
i
m
il
ar to t
h
ose
i
n
l
ow-
p
res-
sure
di
sc
h
ar
g
e tec
h
no
l
o
g
y
.
3.3 Influence of harmonic waves and corresponding
fil
t
e
r
s
T
he development o
f
modern semiconductor technolo
g
y
with a si
g
ni
f
icant increase in the number o
f
consum
-
e
r
s
with
so
li
d
s
t
a
t
e
s
wit
c
h
es
a
n
d
co
nv
e
rt
e
r
co
ntr
o
ll
e
r
s
u
n
f
ortunatel
y
results in undesirable side-e
ff
ects on the
AC
volta
g
e supply by causin
g
considerable inductive
watt
l
ess power an
d
non-s
i
nuso
id
a
l
current.
A
t
y
pical converter current consists of various super-
im
p
osed sinusoidal
p
artial currents, i.e. a
f
irst
h
armonic with the suppl
y
f
requenc
y
, and a number o
f
•
Elec
tr
o
n
ic
ballas
t
s
a
r
e
s
t
a
t
e
of
t
he
a
rt.
•
Elec
tr
o
n
ic
ballas
t
s
ca
n
be
used
t
o
achie
v
e
sig
n
ifi
cant
i
ncreases
i
n qua
li
t
y
, re
li
a
bili
t
y
an
d
s
a
f
et
y
o
f
ligh
t
i
n
g
s
y
stems w
i
t
h
meta
l
h
a
lid
e
l
am
p
s.
•
M
ost new
MH
ligh
t
i
n
g
i
nsta
ll
at
i
ons to
d
a
y
are
al
rea
dy
equ
i
ppe
d
w
i
t
h
e
l
ectron
i
c
b
a
ll
asts.
1
6
so-called harmonic waves whose
f
re
q
uencies are a
multiple of the suppl
y
frequenc
y
(
in three-phase sup-
plies these are mainl
y
the
f
i
f
th, seventh and eleventh
harmonic waves
).
These harmonic waves increase the current of the ca
-
p
acitor
f
or
p
ower
f
actor correction, as the reactance
o
f
a capacitor decreases with increasin
g
f
requency
.
Th
e
i
ncreas
i
n
g
capac
i
tor current can
b
e accommo
d
at
-
ed by improvin
g
the desi
g
n o
f
the capacitor, but this
does not eliminate the risk o
f
resonance
p
henomena
b
etween t
h
e power capac
i
tors on t
h
e one
h
an
d
an
d
the inductance o
f
the
f
eedin
g
trans
f
ormer and the
g
rid
o
n t
he
o
t
he
r.
The harmonic wave contamination of an A
C
volta
g
e
supply can have some or all o
f
the
f
ollowin
g
e
ff
ects
:
• earl
y
f
ailure o
f
capacitor
s
• premature tri
gg
erin
g
o
f
protective switches and
other sa
f
et
y
device
s
•
f
ailure or mal
f
unction o
f
computers, drivers,
ligh
t
i
n
g
i
nsta
ll
at
i
ons an
d
ot
h
er sens
i
t
i
ve
co
n
su
m
ers
• thermal overload o
f
trans
f
ormers caused b
y
i
n
c
r
eased
i
r
o
n
losses
• overload of the neutral conductor
(
particularl
y
by
t
h
e
3
r
d
harmonic wave
)
• shatterin
g
or burstin
g
o
f
dischar
g
e lamp
s
• thermal overload o
f
the lam
p
choke due to reso-
nance between choke and ca
p
acitor
f
or
p
owe
r
fac
t
o
r
co
rr
ec
ti
o
n. Th
e
effec
t
s
ca
n
be
s
imil
a
r t
o
as
y
mmetrical mode
(
see chapter 6.2.9
)
, which is
wh
y
the use o
f
a choke with thermal protection
can also protect the luminaire
f
rom burnin
g.
The installation of so-called choked ca
p
acitors
(
ca-
pacitor in series with a filter choke
)
aims at forcin
g
the
resonance
f
requency o
f
the
g
rid below the
f
requency
o
f
the lowest prevailin
g
harmonic wave. This prevents
a resonance between the capacitors and the
g
rid and
w
ould thus also
p
revent the am
p
li
f
ication o
f
the har
-
m
o
ni
c
cu
rr
e
nt
s
. Thi
s
kin
d
of
in
s
t
a
ll
a
ti
o
n
a
l
so
h
as
a
f
il
-
terin
g
e
ff
ect by reducin
g
the level o
f
volta
g
e distortion
in the
g
rid. It is there
f
ore recommended
f
or all cases
w
here the watta
g
e share of the loads that
g
enerate
harmonic waves is more than 20
%
o
f
the total watt-
a
g
e. The resonance
f
requency o
f
a choked capacito
r
alwa
y
s lies below the
f
requenc
y
o
f
the
5
t
h
ha
rm
o
n
ic
wa
v
e.
In the electronic ballast
OS
RAM P
O
WERTR
O
NI
C
®
PTi,
the in
f
luence o
f
harmonic waves on the lamp is kept
extens
i
ve
l
y at
b
ay
b
y t
h
e
b
a
ll
ast
d
es
ig
n w
hi
c
h
com
-
prises an intermediate circuit. The immunit
y
o
f
the PTi
input sta
g
e to line-related inter
f
erence is sa
f
e
g
uarded
by tests according to the IE
C
61000 standard
.
S
uch line-related interference includes e.
g
.:
• burst as per IE
C
61000-4-4, 1000V peak, repetition
f
requency 5kHz, low-ener
g
y puls
e
• current feed as per IE
C
61000-4-6, frequenc
y
ran
g
e 0.15-80
MH
z, 3
V
rms
• sur
g
e as per IE
C
61000-4-5, 1000V symmetrical,
2000
V
asymmetr
i
ca
l
,
high
-ener
g
y pu
l
se
• volta
g
e interruptions as per IE
C
61000-4-1
1
• volta
g
e
f
luctuation
s
3
.4
B
r
i
e
f
vo
l
ta
g
e
i
nterrupt
i
ons
When the lam
p
current
f
alls, the recombination rate
starts to excee
d
t
h
e
i
on
i
zat
i
on rate, caus
i
n
g
a re
d
uc
-
tion in plasma conductivity. This occurs with ma
g
netic
ballasts in every hal
f
-wave on passin
g
the zero cross-
i
n
g
an
d
resu
l
ts
i
n t
h
e so-ca
ll
e
d
re-
ig
n
i
t
i
on pea
k
.
Wh
en
recombination o
f
the char
g
ed particles has pro
g
ressed
f
ar enou
g
h, the remainin
g
quantity o
f
char
g
e carriers is
not su
ff
icient enou
g
h to
g
enerate an adequate quan-
tity o
f
new charge carriers when the voltage increases
a
g
a
i
n – t
h
e
l
amp
g
oes out.
Th
e
high
pressures
i
n t
h
e
arc tu
b
e mean t
h
at t
h
e
ig
n
i
t
i
on vo
l
ta
g
e
i
s now no
l
on-
g
er su
ff
icient to re-i
g
nite the lamp. It has to
f
irst cool
down for a few minutes before it can i
g
nite a
g
ain
(
see
a
l
so c
h
a
p
ter 4.2
“W
arm re-
i
gn
i
t
i
on
”
).
Wh
en t
h
e supp
l
y vo
l
ta
g
e
i
s
i
nterrupte
d
,
b
ot
h
t
h
e
l
en
g
t
h
and depth of the interruption
(
100% for complete
interruption
)
and the phasin
g
of the interruption are
im
p
ortant.
O
lder lam
p
s with their increase in lam
p
volt
-
a
g
e an
d
high
er re-
ig
n
i
t
i
on vo
l
ta
g
e are more sens
i
t
i
ve
than una
g
ed lamps. The capacitor
f
or power
f
actor
correct
i
on can act as vo
l
ta
g
e source
d
ur
i
n
g
vo
l
ta
g
e
i
nterru
p
t
i
ons, at
l
east
i
n t
h
e s
h
ort term, an
d
exten
d
t
h
e
time in which a volta
g
e interruption is tolerated be
f
ore
the lamp
g
oes o
ff
. Volta
g
e interruptions just be
f
ore the
zero cross
i
n
g
are more ser
i
ous,
b
ecause t
h
e p
l
asma
has already cooled down si
g
ni
f
icantly.
If
t
h
e resonance
f
requenc
y
o
f
a resonance c
i
rcu
i
t
cons
i
st
i
n
g
o
f
power capac
i
tors an
d
i
n
d
uctance o
f
t
h
e
f
ee
di
n
g
trans
f
ormer
i
s near enou
gh
to t
h
e
f
requenc
y
of
a
h
armon
i
c wave
i
n t
h
e
g
r
id
, t
hi
s resonance c
i
rcu
i
t
can amp
lify
t
h
e osc
ill
at
i
on o
f
t
h
e
h
armon
i
c waves an
d
cause immense overcurrent and overvolta
g
e.
17
3.5
S
trobosco
p
ic effect and flicke
r
O
peration of a metal halide lamp on a ma
g
netic ballast
u
nder supply voltage with 50 Hz
f
requency results in
p
eriodic
f
luctuation o
f
the luminous
f
lux with double
the suppl
y
f
requenc
y
. When the current
f
low drops
n
ear the zero crossin
g
, the plasma also has
f
ar less
ra
di
at
i
on.
B
ut even on pass
i
n
g
t
h
e zero cross
i
n
g
, t
h
e
luminous
f
lux does not reach zero so that the
p
lasma
st
ill
h
as on-
g
o
i
n
g
ra
di
at
i
on.
The human eye reacts with di
ff
erin
g
sensitivity to
varyin
g
f
licker
f
requencies, and can,
f
or example, no
lon
g
er perceive
f
luctuations in luminous
f
lux above
100 Hz. Literature provides di
ff
erin
g
ways o
f
depictin
g
the sensitivit
y
o
f
the human e
y
e
f
or periodic luminous
f
lux
f
luctuations at various
f
requencies. Fi
g
. 17 shows
an example accordin
g
to Kelly and Hen
g
er
[
1
].
When operatin
g
at 50 Hz, the luminous
f
lux or intensity
f
luctuates with watta
g
e, i.e. with 100 Hz as shown in
Fig
. 15.
Li
terature uses var
i
ous equat
i
ons to eva
l
uate
chan
g
es in luminous intensity that can be perceived
b
y t
h
e
h
uman eye.
Fli
c
k
er
i
s eva
l
uate
d
accor
di
n
g
to
EN 50006 standard,
f
or exam
p
le, with a
f
licker
f
actor
F
1
0
as
whereb
y
m
(f
i
)
= time-de
p
endent modulation de
p
th
of
the luminous intensit
y
G
= filter curve for flicker sensitivit
y
dependin
g
on
f
licker
f
requenc
y
A
ccordin
g
to Afshar
[
2
]
, adaptin
g
the evaluation also to
short-term changes and implementation in a
f
ilter
f
o
r
a li
g
ht si
g
nal, such as in Fi
g
. 15, results in values
f
or
the
f
licker
f
actor as shown in Fig. 16. The perceptibility
t
h
r
eshold
is
assu
m
ed
t
o
be
1.
The
v
alues
i
n t
his
e
x-
amp
l
e rema
i
n
b
e
l
ow 1,
i
.e. no v
i
s
ibl
e c
h
anges can
b
e
perce
i
ve
d
i
n t
h
e
ligh
t
.
()
∑
=
i
ii
fGfmF )²
1
0
²
)
Fi
g
. 15: Luminous intensit
y
o
f
a metal halide lamp at
50
H
z c
h
o
k
e operat
i
on, s
h
own
i
n ar
bi
trar
y
un
i
t
s
Fi
g
. 16: Flicker
f
actor calculated
f
rom the luminous
i
ntensit
y
si
g
nal
f
or a metal halide lamp at 50 Hz choke
operat
i
on, s
h
own
i
n ar
bi
trar
y
un
i
ts
Fig. 17: Eye sensitivity curve
f
or
f
licker as per Kelly
1960 and Hen
g
er 1985
1
8
3
1
4
2
+200V
+8A
+7.97V
+400V
A
V
V
MP
ow
e
r
P
ow
er
D
C
RM
S:
15
0
.5
2
VA
MImpe
d
ance Impe
d
ance D
C
RM
S:
Un
d
er rang
e
T-
M
-
-
Window 1
-400V
A
V
V
-0.033V
-8A
-200V
M-
M
Ch 1: Lamp voltage Ch 3: Light signal (zero-line at the bottom)
Ch 2: Lamp current
C
h 4: Lamp powe
r
Fi
g
. 18: Time curve
f
or li
g
ht si
g
nal and the electric parameters o
f
a metal halide lamp
There is a dela
y
o
f
just a millisecond between the
current maximum and the luminous
f
lux maximum as
shown in the
f
ollowin
g
drawin
g.
In fast-movin
g
or rotatin
g
ob
j
ects, the stroboscope effect can cause an optical illusion that the ob
j
ect is
mov
i
n
g
more s
l
ow
ly
or
i
n t
h
e oppos
i
te
di
rect
i
on or even at a stan
d
st
ill
.
S
troboscope effects can be reduced or ruled out b
y
operatin
g
luminaire
g
roups on three different phases
or
by
us
i
n
g
e
l
ectron
i
c
b
a
ll
asts
.
1
9
4 I
g
n
i
t
i
n
g
and start
i
n
g
d
i
schar
g
e lamp
s
S
ome dischar
g
e lamps do not require an external
i
g
nition unit, as the supply volta
g
e is su
ff
icient to
ignite the lamp or because the lamp has an integrated
ig
n
i
t
i
on un
i
t.
Th
ese
l
amps must n
ot
b
e use
d
i
n
i
nsta
ll
a
-
tions with an external i
g
nition unit or they will
f
ail pre
-
mature
l
y
d
ue to
i
nterna
l
arc
i
n
g.
All
ot
h
er
di
sc
h
ar
g
e
l
amps must
b
e
ig
n
i
te
d
b
y an a
ddi-
tional unit. Ignition units or circuits o
f
varying types are
used
f
or this purpose
.
A
t room temperature, the
f
illin
g
particles are still pres
-
ent in solid form
(
metal halides or amal
g
am
)
or in liquid
form
(
mercury
)
. The arc tube contains the start gas,
usua
ll
y an
i
nert
g
as suc
h
as ar
g
on or xenon,
b
etween
the electrodes. The insulatin
g
g
as
f
illin
g
in the arc
tu
b
e must
b
e ma
d
e con
d
uct
i
ve
i
n or
d
er to
g
enerate
h
ot p
l
asma.
Thi
s
i
s carr
i
e
d
out
b
y
high
-vo
l
ta
g
e pu
l
ses
g
enerate
d
b
y a separate
ig
n
i
t
i
on un
i
t or
b
y t
h
e
ig
n
i-
tion unit in an electronic ballast.
C
onstantl
y
available
free char
g
e carriers
(
electrons
)
are accelerated by hi
g
h
volta
g
e, providin
g
them with su
ff
icient ener
g
y to ionize
atoms on impact and
g
enerate more
f
ree char
g
e carri-
ers. This process, similar to an avalanche,
f
inall
y
pro
-
duces conductive hot
p
lasma within which the current
f
low excites the partly evaporated metal halide
f
illin
g
suc
h
t
h
at
ligh
t
i
s ra
di
ate
d.
Th
e
ig
n
i
t
i
on vo
l
ta
g
e requ
i
re
d
to
g
enerate a
b
rea
kd
own
between the electrodes depends on the spacing be
-
tween the electrodes, the
f
illin
g
pressure o
f
the
g
as
between the electrodes and the type o
f
g
as. Examples
f
or usin
g
these principles include the use o
f
auxiliary
electrodes or the use of Pennin
g
g
ases
(
see chapter
14.4
“I
g
nition at low i
g
nition volta
g
e
(
Pennin
g
effect
)
”
).
The sockets and cables must be suitably desi
g
ned
f
or
t
h
e
high
ig
n
i
t
i
on vo
l
ta
g
es.
I
n part
i
cu
l
ar w
i
t
h
t
h
e
E
27
sockets
f
or sin
g
le-ended screw base dischar
g
e lamps,
care must be taken that a similar socket
(
E27
)
for in
-
candescent lam
p
s is not used, which does not meet
t
h
e re
q
u
i
rements
.
When lamps are de
f
ective or no lamp is inserted,
continuous operation o
f
the i
g
nition unit can possibly
dama
g
e the i
g
nition unit or the luminaire. It is there
f
ore
advisable to switch the i
g
nition unit o
ff
f
or a period o
f
time a
f
ter
f
ailed i
g
nition, or to use an i
g
nition unit with
tim
e
r
fu
n
c
ti
o
n
.
4.1
E
xterna
l
ig
n
i
t
i
on un
i
t
s
4.1.1 Parallel ignition uni
t
Wi
t
h
a pu
l
se
ig
n
i
t
i
on un
i
t, t
h
e c
h
o
k
e must
b
e
i
nsu
l
ate
d
f
or its sur
g
es. The pulse i
g
nition units can normally
take a load o
f
1000 pF, permittin
g
lead len
g
ths o
f
about 15 m between lamp and choke. Durin
g
i
g
nition,
the lead carries hi
g
h volta
g
e
f
rom the choke to the
l
amp so t
h
at care must
b
e ta
k
en to ensure t
h
at t
h
e
supp
ly
l
ea
d
, soc
k
et an
d
l
um
i
na
i
re are a
d
equate
ly
i
n-
sulated
f
or the correspondin
g
hi
g
h i
g
nition volta
g
e.
T
his type o
f
i
g
nition unit is used in sin
g
le phase
g
rids
.
4.1.2
S
emi-parallel ignition unit
In the semi-parallel i
g
nition unit, part o
f
the choke
windin
g
s is used to trans
f
orm the i
g
nition pulses. This
m
eans the choke must be adequatel
y
insulated
f
or the
h
i
g
h volta
g
e and have a tap
f
or the i
g
nition unit. As
with pulse i
g
nition units, the i
g
nition unit can
g
ener-
ally take 1000 pF or approx. 15 m lead len
g
th, and
t
h
e connect
i
on
l
ea
d
b
etween c
h
o
k
e an
d
l
am
p
must
be insulated
f
or the correspondin
g
volta
g
e levels. A
capac
i
tor w
i
t
h
m
i
n
i
mum capac
i
tance
d
epen
di
n
g
on t
h
e
u
nit must be
p
rovided for com
p
liance with the EM
C
o
f
the i
g
nition unit
.
P
re
f
erence s
h
ou
ld
b
e
gi
ven to us
i
n
g
a t
i
me
r
i
g
nition unit
.
U
S
Luminaire
Lamp
U
choke
Capacitor for
PFC
Pulser
ignition unit
Fi
g
. 19:
S
implified circuit dia
g
ram for conventional
operation o
f
hi
g
h intensit
y
dischar
g
e lamps with pulse
ig
n
i
t
i
on un
it
S
Luminaire
Lamp
U
choke
Capacitor for
PFC
Semi-parallel
ignition unit
Fi
g
. 20:
S
implified circuit dia
g
ram for conventional
o
peration o
f
hi
g
h intensit
y
dischar
g
e lamps with a
s
em
i
-para
ll
e
l
ig
n
i
t
i
on un
i
t
2
0
4.1.3 Superimposed ignito
r
I
n a super
i
mpose
d
ig
n
i
t
i
on un
i
t, t
h
e
high
vo
l
ta
g
e
i
s
onl
y
present at the lamp outputs o
f
the unit. Depend
-
in
g
on cable and structure, i
g
nition units o
f
this type
can normally take loads o
f
100 pF, correspondin
g
to
a lead len
g
th o
f
about 1.5 m
.
4.
2
W
arm re-
ig
n
i
t
i
o
n
N
orma
l
ig
n
i
t
i
on vo
l
ta
g
es
i
n t
h
e ran
g
e up to 5
kV
d
o
not permit immediate re-i
g
nition o
f
a lamp which is
st
ill
h
ot.
Th
e
high
operat
i
n
g
pressures
d
eman
d
ig
n
i
t
i
on
volta
g
es o
f
e.
g
. 25 kV. I
f
a lamp
g
oes out
f
or instance
because o
f
a brie
f
interruption in the supply volta
g
e, it
must cool down for a few minutes
(
for lamp watta
g
es
<
150 W
)
until the fallin
g
pressure in the arc tube per-
mits re-i
g
nition
f
or normal i
g
nition units in the 5k
V
ran
g
e.
High
er watta
g
e
l
eve
l
s requ
i
re cons
id
era
bl
y
longer cooling down periods because o
f
the highe
r
t
h
erma
l
capac
i
ty.
Th
e coo
li
n
g
d
own process
d
epen
d
s
a
l
so on t
h
e am
bi
ent temperature an
d
t
h
e
l
um
i
na
i
re.
A
narrow,
h
ot
l
um
i
na
i
re pro
l
on
g
s t
h
e coo
li
n
g
d
own pro-
cedure, delayin
g
re-i
g
nition o
f
the lamp
.
This cool down time must be considered
f
or ignition
un
i
ts w
i
t
h
a t
i
mer cut-out w
hi
c
h
are
d
es
ig
ne
d
to s
h
ut
o
ff
a
f
ter a certain period o
f
time with
f
ailed i
g
nition.
The desi
g
n intent assumes that the lamp is de
f
ective
or not
i
nserte
d
.
Th
e se
l
ecte
d
t
i
mer
p
er
i
o
d
must
b
e
su
ff
icient to allow the lamp enou
g
h time to cool down
f
ollowin
g
a power interruption so that lamp re-i
g
nition
is a
g
ain possible. The warm re-i
g
nition times o
f
the
P
O
WERBAL
L
®
are under 10 minutes
,
f
ar shorter than
those o
f
the c
y
lindrical version
.
4.
3
H
ot re-
ig
n
i
t
i
o
n
Hi
g
h i
g
nition volta
g
es o
f
16 to 60 kV are necessary
f
o
r
immediate re-i
g
nition of hot metal halide lamps
(
hot
re-i
g
nition
)
on account of the hi
g
h vapor pressures.
The lamp, sockets and luminaire must be desi
g
ned
f
o
r
these hi
g
h volta
g
es, and suitable i
g
nition units must
be used. There are two versions o
f
hot re-i
g
nition units
w
i
t
h
symmetr
i
ca
l
an
d
asymmetr
i
ca
l
i
gn
i
t
i
on pu
l
ses.
I
n
t
h
e as
y
mmetr
i
ca
l
un
i
ts, care must
b
e pa
id
to correct
polarit
y
o
f
the lamp connections
!
A
t present, hot re-i
g
nition is permitted
f
or double
-
ended
q
uartz lam
p
s
(
with a few exce
p
tions
)
. As far
as ceram
i
c
l
amps are concerne
d
, t
h
e s
i
n
gl
e-en
d
e
d
H
C
I
®
-TM series with
G
Y22 socket are approved for
h
ot re-i
g
nition. Approval o
f
other double-ended ce
-
ram
i
c
l
am
p
s
i
s
i
n
p
re
p
arat
i
on
.
4.4 Ignition at low ignition voltage
(
Penning effect
)
V
ar
i
ous met
h
o
d
s can
b
e use
d
to re
d
uce t
h
e vo
l
ta
g
e
n
ecessary to i
g
nite the lamp.
O
ne such method uses
the so-called Pennin
g
e
ff
ect. When the ener
g
y stored
in a meta-stable excitation level o
f
the basic
g
as is
lar
g
er than the ionization ener
g
y o
f
the admixture, vol-
u
me ionization be
g
ins at lower
f
ield stren
g
ths, result-
in
g
in a lar
g
er number o
f
char
g
e carriers at the same
volta
g
e than in pure
g
as. Examples
f
or the Pennin
g
e
ff
ect include mercury in ar
g
on
f
or metal halide lamps
and ar
g
on in neon
f
or some dischar
g
e lamps.
4.5
Ig
n
i
t
i
on at
l
ow am
bi
ent temperatures
M
ost meta
l
h
a
lid
e
l
amps w
i
t
h
watta
g
es
<
400
W
can be operated at ambient temperatures of – 50 °
C
.
Th
e usua
lly
evacuate
d
outer
b
u
lb
an
d
t
h
e
l
um
i
na
i
re
ensure t
h
at t
h
e arc tu
b
e
i
s t
h
erma
lly
d
ecoup
l
e
d
f
rom the surroundings, so that the normal operating
p
arameters are achieved as
f
ar as
p
ossible. For
H
QI
®
2000
W
NI
an
d
2000
W
DI
,
ig
n
i
t
i
on
i
s on
l
y
permitted to – 20 °
C.
In the i
g
nition units, the
f
errite core is sensitive to tem-
perature, that is, the rated ignition voltage is lower at
lower temperatures.
S
ome i
g
nition unit manufacturers
recommend the use o
f
i
g
nition units without cut-out,
as the
f
errite core in this case is heated up b
y
the loss-
es durin
g
f
ailed i
g
nition attempts so that the speci
f
ied
i
g
nition pulse levels are reached a
g
ain. There are also
i
g
nition units with an additional inte
g
rated resistor
f
o
r
h
eat
i
n
g
t
h
e
ig
n
i
t
i
on un
i
t so t
h
at t
h
ese are approve
d
for temperatures down to – 50 °
C
. Here a
g
ain, it takes
a while a
f
ter switchin
g
the i
g
nition unit on until it has
heated up enou
g
h to reach the speci
f
ied i
g
nition pulse
l
e
v
e
l
s.
For speci
f
ic applications such as in cold stora
g
e hous-
es, semi-parallel i
g
nition units can be used
(
which per-
mit lon
g
er lead len
g
ths
)
that are fitted in warmer zones
ou
t
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i
de
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u
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ir
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S
Luminaire
Lamp
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choke
Capacitor for
PFC
Superimposed
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Fi
g
. 21:
S
implified circuit dia
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ram for conventional
operation o
f
hi
g
h intensit
y
dischar
g
e lamps with a
s
uper
i
mpose
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ig
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i
t
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on un
i
t
Th
e t
i
mer per
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o
d
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on un
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ts w
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t
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warm
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i
gn
i
t
i
on must
b
e appropr
i
ate
l
y
l
ong enoug
h
.
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