R.V.R. Elettronica EDL1000-FM User manual

Brand
R.V.R. Elettronica
Model
EDL1000-FM
Type
User manual
EDL1000-FM
User manual
Manufactured by Italy
Table of contents
1. Introduction 1
2. Working principle 1
3. External description 2
4. Power derating 2
5. Technical specifications 3
4. Schematics and images 3
EDL1000-FM
iUser manual Rev. 1.1 - 08/03/07
EDL1000-FM
1 / 6User Manual Rev. 1.1 - 08/03/07
1. Introduction
The EDL1000-FM is a dummy load produced by RVR Elettronica SpA to be used
with FM transmitter with nominal power up to 1000 W.
Dummy loads are mainly used as laboratory test devices and are often included in
redundant (1+1 or N+1) transmission systems, in which the output of the spare
transmitter is normally connected to the dummy load for test pourpouses.
The EDL1000-FM is particularily suited for the use in transmission systems, thanks
to its form-factor (rack mountable in standard 19 racks) and the availability of interlock
connectors to link it with the changeover unit.
2. Working principle
Simply speaking, the EDL1000-FM is just a 50 Ω resistive load, optimized to work in
the audio FM band.
The applied power is dissipated by four 50 Ω power resistors connected in a series/
parallel configuration (see the enclosed schematic). Three inductors are used to
compensate the parasitic capacitance of the resistors, to obtain a return loss better
than 20 dB on the whole 87.5 - 108 MHz band.
The resistors are fixed on a metal heatsink, and three fans generate the air flow to let
the heat pass to the environment.
The fans are activated by a thermal bimetallic switch, that is normally opened and will
close as soon as the heatsinks temperature surpasses 50 °C.
Another thermal bimetallic switch, normally closed, opens as soon as the temperature
surpasses 90 °C. The status of this switch has the meaning of an interlock, and is
available on two connectors, a DB25 and a BNC.
!
WARNING: Always connect the power source (the transmitter) using the interlock
connectors, to avoid the possibility of an excessive temperature rise that could
damage the dummy load and even the transmitter itself!
EDL1000-FM
2 / 6 User ManualRev. 1.1 - 08/03/07
3. External description
The front panel of the EDL1000-FM only contains the grid for the airflow.
!
WARNING: dont cover the airflow grid, to ensure proper functioning of the device.
Figure 1: Front panel
1
2
3
4
5
6
Figura 2: Rear panel
[1] Input connector (7/16)
[2] Interlock connector. DB25 with pin 17 normally connected to ground, floating in
case of interlock
[3] Interlock connectors. BNC with inner normally grounded, floating in case of interlock
[4] Mains fuses for the fans (1A rapid each)
[5] VDE plug for mains supply (220 AC)
[6] Fans
EDL1000-FM
3 / 6User Manual Rev. 1.1 - 08/03/07
4. Power derating
The power that the EDL1000-FM can continuosly dissipate depends on the
temperature of the environment.
Since the dummy load can work at a temperature up to 90 °C before the protection
device is triggered, figure 2 gives the acceptable working area of the device.
!
WARNING: Please remember that it is essential to link the transmitter to the interlock
connectors of the EDL1000-FM, to avoid the risk of damaging it.
10 20 30 40 50 60 70 80
250
500
750
1000
1200
Watt
°C
External temperature
Figure 3: Working area
5. Techical specifications
Frequency band 87.5 - 108.0 MHz
Nominal power at 40°C 1000 W
Power derating at t > 40 °C 2 W/°C
Return loss > 20 dB
Power supply 220V ac +/- 10%
Fuse 2 A
Size (L x H x D) 483 x 132 x 510 mm
Weight 19 kg
6. Schematics and images
This chapter contains the schematic of the EDL1000-FM, and some image of the
internal of the device
In Figure 3, please nothe the two thermal switches. The upper one, protected by a
plate to avoid hazardous contact with the ac voltage, is used to switch on the fans.
The second switch is the interlock one.
EDL1000-FM
4 / 6 User ManualRev. 1.1 - 08/03/07
4650N
230V
Terminal block
4 terminals
4650N
230V
4650N
230V
CSPWRSENHC5
32-1005
32-1005
31-1005
RG303
RF IN
31-1005
BNC
BNC
EDL1000-FM
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1
D. Canazza - REV.: BERTI J.
EDL1000 Schematic
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FAN1
CN1
VDE MAINS IN
1
3
2
F1 2A
FAN2
F2 2A
FAN3
F3 2A
TH1
Therm NO 50°C
L1
CN3
EIA 7/16"
R2
50R
R4
50R
R3
50R
CN4
L2C3
4n7
C1
4n7
CN5
R1
50R
TH2
Therm NC 90°C
C2
4n7
L3
TH3
Therm NO 90°C
CN2
DB25FF
13
25
12
24
11
23
10
22
9
21
8
20
7
19
6
18
5
17
4
16
3
15
2
14
1
C4
4n7
EDL1000-FM
5 / 6User Manual Rev. 1.1 - 08/03/07
Bill Of Materials
Item Q.ty Ref Description
____________________________________________________________
1 1 CN1 VDE MAINS IN
2 1 CN2 DB25FF
3 1 CN3 EIA 7/16"
4 2 CN4,CN5 BNC_IS90
5 4 C1,C2,C3,C4 4n7
6 1 FAN1 4650N 220V
7 2 FAN2,FAN3 FAN
8 3 F1,F2,F3 2A
9 3 L1,L2,L3 IND
10 4 R1,R2,R3,R4 50R
11 1 TB1 STM08D
12 1 TH1 Therm NO 50°C
13 1 TH2 Therm NC 90°C
14 1 TH3 Therm NO 90°C
Figure 4 - Power resistors and thermal switches
EDL1000-FM
6 / 6 User ManualRev. 1.1 - 08/03/07
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R.V.R. Elettronica EDL1000-FM User manual

Brand
R.V.R. Elettronica
Model
EDL1000-FM
Type
User manual
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