ESAB LPH 50 User manual

LPH 50

PLASMA ARC CUTTING SET

Service manual

0349 300 023 01-02-12 Valid from Serial No. 107 XXX-XXXX

! WARNING !

ARC WELDING AND CUTTING CAN BE INJURIOUS TO YOURSELF AND OTHERS. TAKE

PRECAUTIONS WHEN WELDING. ASK YOUR EMPLOYER FOR SAFETY PRACTICES THAT

SHOULD BE BASED ON MANUFACTURER’S HAZARD DATA.

ELECTRIC SHOCK - Can kill

- Install equipment in accordance with obligatory standards.

- Do not touch live electrical parts or electrodes with bare skin, wet gloves or wet clothes.

- Insulate yourself from earth and workpiece.

- Ensure your work position is safe.

FUMES AND GASES - Can be dangerous to your health

- Keep your head away from fumes.

- Use ventilation and/or extraction to keep fumes and gases away from your breathing zone

and surroundings.

ARC RAYS - Can injure eyes and burn skin

- Protect your eyes and skin. Use correct welding screens, filter lens and wear protective clothes.

- Protect bystanders with suitable screens or curtains.

FIRE HAZARD

- Sparks (spatter) can cause fire. Make therefore sure there are no inflammable materials nearby.

NOISE - Excessive noise can damage your hearing.

- Protect your ears. Use ear defenders or other hearing protection.

- Warn bystanders of the risk.

READ AND UNDERSTAND THE INSTRUCTION MANUAL BEFORE INSTALLING OR OPERATING UNIT

PROTECT YOURSELF AND OTHERS !

1. TECHNICAL DATA .................................................................................................................... 3

2. MAINTENANCE ......................................................................................................................... 3

2.1 General ........................................................................................................................ 3

2.2 Inspection and cleaning ............................................................................................... 3

2.3 PT 27 consumable parts .............................................................................................. 3

2.4 Flow switch .................................................................................................................. 4

2.5 Filter ............................................................................................................................. 5

3. TROUBLESHOOTING ............................................................................................................... 5

3.1 General ........................................................................................................................ 5

3.2 Troubleshooting guide ................................................................................................. 6

3.3 Test procedures ........................................................................................................... 7

3.4 Sequence of operation ................................................................................................. 9

3.5 Control board ............................................................................................................... 10

3.6 Schematic diagram ...................................................................................................... 11

3.7 Air connections diagram .............................................................................................. 12

4. REPLACEMENT PARTS ...........................................................................................................13

! CAUTION !

Maintenance and Repair works should be performed by an experienced staff, and electrical

works only by trained electrician. Do not permit untrained persons to inspect, clean, or repair

equipment. Use recommended spare parts only.

1 TECHNICAL DATA

Rated 60% Duty Cycle 50A 50A

Output 100% Duty Cycle 30A 30A

Output Current Range

30÷50A 30÷50A

Open Circuit Voltage (max) 320V 320V

Supply cable cross section mm

4 x 2,5 4x6/ 4x2,5/ 4x2,5

Rated primary input (max) 400-415V 3~50/60Hz

24A/phase

230V/400-415V/440V

3~50/60Hz

42A/24A/22A/phase

Air Requirements PT 27 118 l/min 4,5bar 118 l/min 4,5bar

Max. cutting thickness 15 mm 15 mm

Dimensions Length

Height

Width

680

715

325

680

715

325

Weight of LPH 50 89kg 90kg

2 MAINTENANCE

2.1 GENERAL

If equipment doesn’t work properly, stop work immediately and investigate cause of malfunction.

Maintenance work must be performed by experienced person, and electrical work by trained

electrician. Do not permit untrained person to inspect, clean or repair the equipment. Use

recommended spare parts only.

! WARNING !

Be sure that unit is disconnected from mains by pulling out power cable plug of mains socket.

2.2 INSPECTION AND CLEANING

Frequent inspections and cleaning of LPH 80 are recommended for safe and proper operation. Some

suggestions for inspecting and cleaning are listed below:

A. Check work cable (+) for secured connection to workpiece.

B. Check if workpiece and power source are safely earth grounded.

C. Check heat shield on torch. Replace if damaged.

D. Check electrode and nozzle for wear on daily basis.

E. Make sure cable and hoses are not damaged and/or kink.

F. Make sure all plugs, fittings and neutral connections are tight.

G. With power cable disconnected from mains, wearing proper eye and face protection, blow inside

of machine with low-pressure dry compressed air.

CAUTION

Water or oil occasionally accumulate in compressed air lines. Be sure to blow air lines away

from unit to avoid damage of machine.

H. Occasionally drain water from filter below the air pressure regulator.

2.3 PT 27 TORCH CONSUMABLE PARTS.

! WARNING !

Make sure power switch is in OFF position before working on the torch.

! WARNING !

PT 27 torch contains gas flow check valve that acts in conjunction with flow switch and

circuitry inside power source. That system prevents torch from being energised with high

voltage when torch switch is accidentally closed while shield is removed. Always replace torch

with proper one manufactured by ESAB for it contains ESAB’s patented safety interlock.

To assemble consumable parts refer to Fig.2-1.

A. Place nozzle, swirl baffle, electrode and valve pin into shield as shown.

B. Thread assembly on torch body and hand tighten.

Always make sure the shield is very tight before cutting.

Fig. 2-1. Assembly of PT 27 torch head.

2.4 FLOW SWITCH

When excessive air contamination occurs, flow switch (FS-4) should be disassembled and cleaned as

follows:

A. Ensure that system is shut down and that there is no trapped air under pressure in lines.

B. Remove plug.

C. Remove spring. Be careful when handling spring to avoid distortion.

D. Remove piston.

E. Clean all parts with cleaning agent.

NOTE

Make sure cleaning agent doesn’t contain solvents that can dissolve switch body. Warm water

and detergent are recommended for cleaning. Allow all parts to dry thoroughly before

reassembling.

Reassemble the switch in reverse order

Fig. 2-2. Disassembly / Assembly of flow switch.

2.5 FILTER

1. Checking of condensate level.

When condensate level reaches 10 mm, unscrew counter-clockwise knob at the bottom of filter

container and empty it.

2. Too low flow rate.

If flow rate is too low, filter refill (0457290081) is to be replaced. In order to do so, first make sure there

is no compressed air trapped in air lines. Next unscrew filter lid counter-clockwise, than unscrew filter

plate and replace refill.

3 TROUBLESHOOTING

3.1 GENERAL

! WARNING !

ELECTRIC SHOCK CAN KILL! Make sure that machine is totally disconnected from mains by

unplugging its power cable plug from mains socket, before attempting any inspections or work

inside unit.

Check the problem regarding its symptoms in following troubleshooting guide. The solution may be

quite simple. If the cause can not be quickly located, shut off input power, open up the unit, and

perform visual inspection of all components and wiring. Check for secure terminal connections, loose

and/or burned wires and components, bulged or leaking capacitors, or any other sign of damage or

discoloration.

! WARNING !

Voltages found in plasma cutting equipment are high enough to cause serious injury or even

death. Be careful around equipment when covers are removed.

! NOTE !

Before checking voltages in circuit, disconnect power supply from HF generator to prevent voltmeter

from damage and to avoid possible electric shock.

3.2 TROUBLESHOOTING GUIDE

NOTE Refer to p.3.4 and study carefully operation sequence.

A. Connect to mains and turn on the unit.

- Is “POWER” LED (D1, green – front panel) lit?

YES NO

B. Press “AIR TEST” button (S4) on front panel. See p. 3.3.A

- Do gas valve (EZ1) operate (audible click)?

YES NO

- Does the gas flow? See p. 3.3.B

YES NO

See p.3.3.C

C. Release “AIR TEST” button (airflow should stop).

Depress the torch switch (START) – gas should flow immediately (provided that 3.2.B is OK), if not,

see also 3.2.D.

- Do contactors ST1&ST2 operate and D3 lit (after T

delay)?

YES NO

- Does “FAULT” LED (D2 – front panel) lit?

YES NO

See p. 3.3.E See p. 3.3.F

- Does pilot arc ignite?

YES NO See p. 3.3.G

- Does main arc transfer correctly?

YES NO See p. 3.3.H & 3.3.I

D. Check operation sequence – as per p. 3.4.

- Does it comply with Fig.3-1 and “Description”?

YES NO

UNIT is OK! Replace PCB!

(Provided that all of above tests are OK)

3.3 TEST PROCEDURES

A. Power light (D1) does not light.

1. Visually check machine for any damage.

2. Check if fan is running. If not, check following:

a. Check if machine is correctly plugged into mains.

b. Measure voltage level at mains terminal (230V/400-415/440V 3~50/60Hz).

c. Check if circuit breaker Q is closed.

3. If above is OK, check voltage on PCB (PL50) – between test points XP1-XP2 (15V DC±2%):

- if it is OK., check LED D1 on front panel and its connections

- if there is no voltage – check input voltage on connector X1, terminals 9 & 10 (26V DC±10%).

When input voltage is correct, than PCB might be faulty, if PCB is OK, than check fuse F2 (1,6A),

transformer TR2 secondary voltage (terminals 8 & 9, 20 VAC). If above is OK, pull out fuse F2,

disconnect connector X1 and check rectifier bridge PR4 and varistor V1. Depending on test results,

replace faulty apparatus

B. Malfunction of gas valves.

1. Disconnect connector X2 from PCB, check with ohmmeter “AIR TEST” button circuit between

terminals 5 & 6 on female X2, rectify wiring or replace button if necessary and reconnect X2.

2. Check voltage on TR2 secondary terminals 11 & 12 (24 VAC). If not correct, than transformer is

faulty (provided that tests according to 3.2.A.2.a.b.c are OK)

3. Check fuse F1 (1,6 A), replace if open.

4. Disconnect connector X3 and measure voltage between terminals 1 & 2 on female part. It ought to

be 24 VAC, if not check wiring between TR2 and EZ1 check coil continuity and resistance. Rectify

miswiring or replace valve coil if necessary.

5. While X3 disconnected, check with ohmmeter relay contact (K1) between pins 1 & 2 of X3 on PCB.

While “AIR TEST” button is depressed it should be short-circuited, if not PCB is to be replaced.

C. No airflow.

1. Check air supply. Unit requires min. 150l/min @ 4,5-5,2 bars, check supply terminal if necessary.

2. Check air line connections. Tighten if leaking. Check for any obstruction in air line as well.

3. Airflow may be blocked at torch tip. Check torch consumables. Also check for any obstructions in

torch lines.

NOTE: If above is OK, check all parts of air control and distribution circuit as per Fig. 3-7.

D. Start – signal inactive.

1. While depressing torch switch “ON” LED (D3 on PCB) should be lit.

- If not check torch switch and leads. Unplug the torch switch leads at machine terminals, connect

ohmmeter to the leads. After switch is depressed it should read short. If not - switch or leads are

defective.

- If signal “ON” is OK – replace PCB (provided that test of p. 3.2.B is OK)

E. “FAULT” LED (D2) is lit.

1. “FAULT” LED flashes (also when torch switch is released):

a) When machine is cold (i.e. it did not work within last 2÷3 hours) and “TE” LED on PCB (D4, Fig. 3-2)

is lit, that means temperature monitoring circuit is faulty. Disconnect connector X1 from PCB and

check with ohmmeter temperature switch WT1 on main transformer and its wiring (terminals 4 & 8 on

female X1). Rectify wiring or replace WT1 if necessary.

b) When machine is hot, let it cool down. If “TE” LED is still lit, follow above p. a).

2. “FAULT” LED lights continuously, but only when gas valves energised and air flows (also in postflow

mode, i.e. when torch switch is released).

NOTE: Only “FAULT” signal (D2) in front panel is masked by signal controlling gas valves;

the “PO” LED (D5 on PCB, Fig. 3-2) lights continuously whenever the air monitoring circuit is open

(independently of valve control).

a) Possible cause – flow rate too low. Refer to test of p. 3.3.C and adjust air parameters.

b) Air switches CZ1, CZ2 or their wiring is faulty. Disconnect connector X1 from PCB and check with

ohmmeter sensors CZ1, CZ2 and its wiring (terminals 3 & 8 on female X1). Rectify wiring or replace

CZ1 and/or CZ2 if necessary.

NOTE: Air switch also might be stuck due to oily air, clean it in accordance with manufacturer’s

instruction or replace it.

F. Main contactor and/or pilot contactor doesn’t operate.

NOTE: since there is applied SAFETY STOP (contactors ST1 & ST2 are switched off when main arc

does not ignite within 2 sec after depressing torch switch), test readings have to be performed within

2 sec after depressing the torch switch or, in order to extend reading time, reed relay ZS1 is to be

bypassed (e.g. by shorting terminals 1 & 2 on X1).

! WARNING !

UTMOST CARE IS TO BE PAID DURING THESE TESTS SINCE 320 VDC APPEARS AT THE

OUTPUT CIRCUIT OF UNIT AND ON THE TORCH !

! WARNING !

BEFORE BEGINNIG OF THE FOLLOWING TESTS DISCONNECT 24V SUPPLY FROM HF UNIT

(terminals T24 and T0).

1. Disconnect connector X3 from PCB (unit turned on):

- Check with voltmeter contacts of output relay on PCB:

terminals 7 & 8 for pilot contactor

terminals 6 & 7 for main contactor.

They should be shorted when torch switch is depressed; preflow delay to take into account. If results

are unsatisfactory – PCB is faulty and should be replaced.

- Check with voltmeter voltage between terminals 7 & 8 and 6 & 7 on female X3 (CAUTION: 220 VAC).

If result is incorrect, than TURN OFF the unit and check contactors coils and its wiring. Rectify wiring

or replace coils if necessary.

Reconnect X3 and supply wires to HF unit.

NOTE: As to checking “FAULT” LED (D2), disconnect connector X1 (machine is turned on), D2 should

be lit. If not, disconnect connector X2 and put ammeter between terminals 1 & 3 of X2 on PCB.

Reading should be 10÷14mA. If so check LED and its wiring, otherwise replace PCB.

NOTE: If contactors operate and “ARC” LED (D3) does not light, disconnect connector X2 from PCB

(unit turned on), put ammeter between terminals 1 & 4 of X2 on PCB and depress torch switch.

Reading should be 10÷14mA. If so check LED and its wiring, otherwise replace PCB.

G. PILOT ARC fault.

(Before tests see “NOTE” in p. 3.3.F !)

1. Check torch. Make sure that heat shield is tight, otherwise safety circuit won’t allow switch to activate

power source.

2. Check, with torch switch depressed HF generator supply voltage (24V) on terminals T24 and T0.

3. Disconnect supply From HF unit (T24 and T0), measure open circuit voltage on output of plasma

unit (290÷310 VDC, as per TECHNICAL DATA).

- If output voltage is not correct, check output wiring, rectifier bridge PR1 and secondary voltage of

main transformer (see “WARNING” in p. 3.3.F !).

- If output DC voltage is OK, turn off supply of plasma unit and check wiring of HF circuit, R3, ST2, L1.

H. HF and pilot arc are on but main arc does not transfer.

1. Make sure work clamp (+) is connected to workpiece, good electrical connection is to be provided.

2. Check torch, replace consumables if necessary, check if all parts completed.

3. Torch must be tight assembled.

I. Poor cutting performance.

1. Check air pressure regulator. It should be adjusted to 4,5 bar.

2. Air supplied to torch should be free from oil and water.

3. Make sure consumables attached to torch are acceptable.

4. Check open circuit voltage (320 VDC, as per TECHNICAL DATA).

5. Check output. Use calibrated 100 amps meter capable of measurements in presence of HF.

3.4 SEQUENCE OF OPERATION

Fig. 3-1. Sequence of operation of power source.

– air preflow time (1÷ 1,5 s)

– SAFETY STOP delay (2 sec), if main arc doesn’t arise within this time the “AL” LED (diode 2)

lights, unit output is disenergised (ST1, ST2 are off) and locked until the torch switch is released.

– air postflow time (1÷ 2 min)

Description of operation sequence.

When start button (torch switch) is depressed – air immediately starts to flow; after 1÷1,5 s (T

– acc.

to Fig. 3-1) contactors ST1 & ST2 operate and HF unit is turned on (via ST2) causing ignition of pilot

arc. When torch head is close to workpiece, main arc ignites (i.e. cutting process begins) and

automatically HF unit is turned off (by signal from reed relay ZS1). If within 2 sec (T

– acc. to Fig. 3-1)

main arc (i.e. cutting) will not start (signal from ZS1), the output power will be shut off (contactors, HF

and D3 are off). So as to resume the work, torch switch is to be released and depressed again. If next

activation of machine will be done within air postflow period (1÷2 min after last stop; T

– acc. to Fig. 3-

1), than unit starts immediately (i.e. without preflow delay). If the postflow time (T

) elapses and torch

switch is depressed again, unit starts work with preflow time.

If main arc breaks during cutting (e.g. a hole in cut material) and torch switch is kept depressed, HF is

automatically turned on and unit tries to resume cutting process. If work is not resumed within 2 sec

), the output power is shut off and starting sequence has to be repeated (release and press again

torch switch).

3.5 CONTROL BOARD

Fig. 3-2. Layout of PL50 PCB.

Control lights of PL50 board

LED no. LED denom. Function

PL (G)

AL (R)

ON (G)

TE (R)

PO (R)

Indicates main arc turned ON.

Indicates absence of main arc longer than 2 sec while torch switch is

depressed (alarm)

Indicates torch switch depressed.

Indicates overheating of power source.

Indicates too low air pressure.

G – green

R – red

Test points:

XP1 - +15V ± 2% (through 2 kohm resistor)

XP2 - GND

3.6 SCHEMATIC DIAGRAM

Fig. 3-3. Schematic diagram LPH 50 – 400-415V

Fig. 3-4. Schematic diagram LPH 50 – 230V

(230V/400-415V/440V)

Fig. 3-5. Schematic diagram LPH 50 – 400-415V

(230V/400-415V/440V)

Fig. 3-6. Schematic diagram LPH 50 – 440V

(230V/400-415V/440V)

3.7 AIR CONNECTIONS DIAGRAM

Fig. 3-7. Air connections diagram of LPH 50.

4 REPLACEMENT PARTS

Item No.

Qty. Req.

400-415V

3~50/60Hz

Qty. Req.

230V/400-415V/440V

3~50/60Hz

Part No. Description

Circuit

symbol

01 1 1 0349 302 130 Stand off guide

Fig. 4−

−−

−1. Assembly of stand off guide

Diagram 1. Cutting current 30A with stand off guide applied

no 0349 302 130

Diagram 2. Cutting current 50A with stand off guide applied

no 0349 302 130

Apply stand off guide on the torch, fasten two screws,

one in the position marked as 50A and the second on

the other side so they would get into the groove.

024681012mm

m/min

01234567

m/min

1. When ordering spare parts please specify machine model, serial number, designation and parts

order numbers as shown in spare parts list. This simplifies dispatch and ensures correct delivery.

Fig. 4-2. LPH 50 Power source – front view

Item No. Qty. Req.

400-415V

3~ 50/60Hz

Qty. Req.

230V/400-415V/440V

3~ 50/60Hz

Part No. Description Circuit

symbol

0457 289 001

0457 289 002

0349 302 053

0457 290 003

0457 290 004

0457 290 005

0457 290 006

0457 289 003

0457 290 010

0457 290 011

0457 290 012

0457 289 005

0558 000 487

0457 289 006

Front cover

Rotary cam – switch

LED – holder ( socket )

LED ( green )

LED ( red )

LED ( yellow )

Push – button switch

Pressure gauge

Current connector – socket

Rubber grommet ( with support sleeve )

Current wire with clamp

Plasma cutting torch PT 27

Side panel

“ + ”

Fig. 4-3. LPH 50 Power source – left side view

Item No. Qty. Req.

400-415V

3~ 50/60Hz

Qty. Req.

230V/400-415V/440V

3~ 50/60Hz

Part No. Description Circuit symbol

30 1 - 0457 289 007 Transformer TR1

30 - 1 0349 302 054 Transformer TR1

31 1 1 0457 289 008

Resistor set (3,75 Ω)

32 2 2 0457 289 009 Resistor

33 1 1 0457 289 010 Contactor 220V ST2

34 1 1 0457 290 020 Ignition block 24V HF

35 1 1 0457 290 021 Choke L1

36 1 - 0457 290 083 Circuit breaker Q

36 - 1 0349 302 055 Circuit breaker Q

39 1 1 0457 289 011 Choke L2

40 2 2 0457 289 012

Swivel wheel ( with brake ) ass′y

41 1 1 0457 289 013 Base frame

42 2 2 0457 289 014

Fixed wheel ass′y

43 1 1 0558 000 410 Flow switch FS-4 CZ1

44 1 1 0457 289 015 Coupler

45 1 1 0457 290 030 Pressure switch CZ2

46 1 1 0457 290 031 Electromagnetic valve EZ1

47 4 4 0457 290 032 Stub pipe

48 0457 290 033

Reinforced PCV hose φ5×1,5

49 10 10 0457 290 034 Hose clip

50 1 1 0558 000 380 Connector – twist LOCK G1

51 1 1 0457 290 035 Stub pipe

52 1 1 0457 290 036 Insulating sleeve

53 1 1 0457 290 037 Special nut

54 1 1 0457 290 038 Double nutted bolt

55 1 1 0457 290 039 Insulating sleeve

57 1 1 0457 289 016 Console

0457 290 042

0457 289 017

Temperature switch

Support (left)

Fig. 4-4. LPH 50 Power source – right side view.

Item No. Qty. Req.

400-415V

3~ 50/60Hz

Qty. Req.

230V/400-415V/440V

3~ 50/60Hz

Part No. Description Circuit symbol

90 1 - 0457 289 018 Transformer TR2

90 - 1 0349 302 056 Transformer TR2

91 1 1 0457 290 044 Current sensor ass’y ZS1

92 1 1 0457 290 045 Electronic PCB PL50

93 1 1 0457 290 046 Rectifier bridge PR2

94 2 2 0457 290 047 Fuse holder

95 2 2 0457 290 048 Fuse 1,6A F1, F2

96 1 - 0457 290 019 Contactor 220V ST1

96 - 1 0349 302 063 Contactor 220V ST1

97 1 1 0457 290 050 Capacitor C6

98 1 1 0457 290 051 Clamping ring

99 1 1 0457 289 020 Grip handle

100 1 1 0457 289 021 Roof

101 1 1 0349 302 076

* Rectifier block ass′y

PR1

102 1 1 0457 290 055

Capacitor 5µF 450/500V

103 1 1 0457 290 056

Resistor 330kΩ 0,25W

104 1 1 0457 290 057

Resistor 22Ω 2W

105 1 1 0457 289 023 Lug

106 1 1 0457 289 024 Support ( right )

107 1 1 0457 289 025 Terminal block ( 2-way )

108 1 1 0457 289 026 Fan support

109 2 2 0457 289 027 Fan M1, M2

110 1 1 0457 290 066 Varistor V1

111 1 1 0457 290 067 Connector X2

112 1 1 0457 290 068 Connector X3

113 1 1 0457 290 069 Connector X1

114 1 1 0457 290 082 Reed – relay contact ZZ

* ATTENTION. Rectifier block of number 0457 289 022 is to be replaced with rectifier block of number

0349 302 076 starting with machines of serial No. 029.

Fig. 4-5. LPH 50 Power source – rear view

Item No. Qty. Req.

400-415V

3~ 50/60Hz

Qty. Req.

230V/400-415V/440V

3~ 50/60Hz

Part No. Description Circuit symbol

180 1 1 0457 289 028 Rear shield

181 1 1 0457 290 071 Quick detachable coupling

182 1 1 0457 290 072 Hose clip

183 1 1 0457 290 073 Pipe stub

184 1 1 0457 289 029 Filter-regulator

185 1 1 0457 290 075 Pipe coupler ( elbow )

186 1 1 0457 290 076 Pipe coupler ( straight )

187 1 1 0457 290 077 Pneumatic hose

188 1 1 0457 289 030 Supply cable

189 1 1 0457 289 032 Cable gland

190 1 1 0457 289 033 Locknut

191 1 1 0457 290 081

Filter cartridge 5µm

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ESAB LPH 50 User manual

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