– 8 –
8.4 DUTY CYCLE
Duty Cycle is a percentage of 10 mins, in which a
machine can operate at a rated load without overheating
and interruption from the thermal cut-out device.
Example:
150A @ 30% Duty factor:
150A welding for 3 minutes.
7 minutes down time.
Example:
95A @ 100% Duty factor:
95A continuous welding to
increase the operation time,
reduce the amperage.
Note: The heating tests have been carried out at
ambient temperature and the duty cycle (duty factor) at
20°C has been determined by simulation.
8.5 THERMAL CUT-OUT – FIG.5
If welding for extended periods, the thermal cut-out will
activate and the signal light
(5)
will illuminate,
prohibiting use of the machine until sufficiently cool.
Caution! After completion of any welding task, leave the
unit connected to the power supply for a sufficient period
to allow the cooling fan to continue working.
5
FIG.
9. MAINTENANCE AND TROUBLESHOOTING
9.1 TROUBLESHOOTING GUIDE
Warning! For your own safety, turn the switch off and remove the plug from the power supply socket.
Problem
Possible cause
Required action
No spark.
Bad clamp connection.
Check clamp connection.
PCB on the inverter is defective
or damaged.
Contact Draper Tools/authorised service
agent for repair/replacement.
No output voltage.
Overheated unit – the thermal
cut-out LED will be illuminated.
Wait for unit to cool and the re-setting of
the thermal cut-out.
Failure of internal relay.
Contact Draper Tools/authorised service
agent for repair/replacement.
PCB on the inverter is defective
or damaged.
Contact Draper Tools/authorised service
agent for repair/replacement.
Incorrect current output.
Current control selector is
defective.
Contact Draper Tools/authorised service
agent for repair/replacement.
Supply voltage is low power.
Check the mains power distribution.
Porous welded joint.
Acid electrode on steel with high
sulphur content.
Use a basic electrode.
Workpieces are too far apart.
Move welded edges closer together.
Workpiece is too cold.
Move slowly at beginning of weld.
Cracks in weld.
Material is contaminated with
dirt, oil, rust.
Clean workpiece before welding
commences (essential for neat beads).
Insufficient current.
Enable sufficient current.
(5)
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