Power Source Problems - Thermal Arc ARCMASTER 300S Service Manual

300/ 400TS and 300/ 400S
3
Pow er Sour ce Probl em s
Description
1. The welding arc cannot be
established.
2. Maximum output welding current
can not be achieved with nominal
Mains supply voltage.
3. Welding current reduces when
welding.
4. No gas flow when the torch trigger
switch is depressed.
5. Gas flow won't shut off.
6. The TIG electrode has been
contaminated due to the gas flow
shutting off before the programmed
POST-FLOW time has elapsed.
8
B A SI C TR O U B LESH O O TI N G
Possible Cause
A. The Primary supply voltage has not
been switched ON.
B. The Welding Power Source switch
is switched OFF.
C. Loose connections internally.
Defective control circuit.
A. Loose welding cable connections.
B. Incorrect welding cable size.
C. Improper input connections.
D. Poor electrode condition.
E. Wrong welding polarity.
A. Gas hose is cut.
B. Gas passage contains impurities.
C. Gas regulator turned off.
D. Torch trigger switch lead is
disconnected or switch/cable is
faulty.
A. Weld Mode (STD, SLOPE,
REPEAT or SPOT) was changed
before POST-FLOW gas time had
finished.
B. Gas valve is faulty.
C. Gas valve jammed open.
D. POST-FLOW control is set to 60
sec.
The Weld Process Mode (STICK, HF
TIG or LIFT TIG) was changed before
POST-FLOW gas time had finished.
Tabl e8-3: Pow er Sour ce Pr obl em s
A. Switch ON the Primary supply
voltage.
B. Switch ON the Welding Power
Source.
C. Have an Accredited Thermal Arc
Service Agent repair the connection.
Have an Accredited Thermal Arc
Service Agent repair the connection.
A. Tighten all welding cable
connections.
B. Use proper size and type of cable.
C. Refer to Section 2.05 Electrical Input
Requirements.
D. Replace electrode.
E. Verify output torch connections.
A. Replace gas hose.
B. Disconnect gas hose from the rear of
Power Source then raise gas
pressure and blow out impurities.
C. Turn gas regulator on.
D. Reconnect lead or repair faulty
switch/cable.
A. Strike an arc to complete the weld
cycle. OR Switch machine off then
on to reset solenoid valve sequence.
B. Have an Accredited Thermal Arc
Service Agent repair or replace the
gas valve.
C. Have an Accredited Thermal Arc
Service Agent repair or replace the
gas valve.
D. Reduce POST-FLOW time.
Do not change Weld Process Mode
before the POST-FLOW gas time had
finished.
8 – 5
Remedy