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Cigweld 175 stops running after 20 seconds. Amps goes down, wire feed decreases until it stops. Any ideas anybody. Im using shielded wire.
- Thread starter Morgi
- Start date
Hello and welcome to the Forum !
Is your welder a traditional transformer-based welder or is it a modern inverter?
If the latter, does it have the same fault when used in MMA ( Arc ) mode?
A possible explanation, regardless of the technology, is that there is a loose, burnt, or corroded connection somewhere in the high-current low-voltage welding circuit. This bad joint heats up as you use the welder and the resistance there increases, dropping more voltage across it until the welder stops.
Is your welder a traditional transformer-based welder or is it a modern inverter?
If the latter, does it have the same fault when used in MMA ( Arc ) mode?
A possible explanation, regardless of the technology, is that there is a loose, burnt, or corroded connection somewhere in the high-current low-voltage welding circuit. This bad joint heats up as you use the welder and the resistance there increases, dropping more voltage across it until the welder stops.
Thanks Eddie. Yes, it does it in arc mode also.Hello and welcome to the Forum !
Is your welder a traditional transformer-based welder or is it a modern inverter?
If the latter, does it have the same fault when used in MMA ( Arc ) mode?
A possible explanation, regardless of the technology, is that there is a loose, burnt, or corroded connection somewhere in the high-current low-voltage welding circuit. This bad joint heats up as you use the welder and the resistance there increases, dropping more voltage across it until the welder stops.
I'll get my electrician to check it out.
Thanks
Thank you for the update confirming that the welder also fails in arc mode.
The fact that this MIG has the option of MMA means that it must be an inverter-based machine.
As @Relic pointed out, the failure of power for both weld current and wirefeed implies that the fault is early in the circuit.
The soft-start feature uses a resistor or thermistor to lessen the initial current surge as the large input capacitors charge. A short time after power-on this is bypassed by a relay, which can often be heard. If the contacts of that relay fail, the dropper will remain in circuit and power will be limited.
I would suggest that you start by disconnecting the machine from the AC mains and waiting an hour or two for the capacitors ( with up to 325v DC ) to safely discharge. Then remove the covers and check for:
- loose push-on spade tags at the back of the mains power switch and on the bridge rectifier ( rectangular alloy block mounted on a heatsink, with 4 tags, - there may be two rectifiers in parallel ). All these connections carry a lot of current and often are not fully inserted or they heat up and come loose. Sometimes to avoid doubt I solder them on.
- loose bolted connections on heavy internal cables and copper or aluminium busbars, at heatsinks, and on thick tracks on the PCBs, at the Euro socket, and the back of the front panel Dinse sockets.
- loose or poorly-seated plugs on the multi-wire harnesses between the PCBs
- any sign of blackened or burnt components.
The fact that this MIG has the option of MMA means that it must be an inverter-based machine.
As @Relic pointed out, the failure of power for both weld current and wirefeed implies that the fault is early in the circuit.
The soft-start feature uses a resistor or thermistor to lessen the initial current surge as the large input capacitors charge. A short time after power-on this is bypassed by a relay, which can often be heard. If the contacts of that relay fail, the dropper will remain in circuit and power will be limited.
I would suggest that you start by disconnecting the machine from the AC mains and waiting an hour or two for the capacitors ( with up to 325v DC ) to safely discharge. Then remove the covers and check for:
- loose push-on spade tags at the back of the mains power switch and on the bridge rectifier ( rectangular alloy block mounted on a heatsink, with 4 tags, - there may be two rectifiers in parallel ). All these connections carry a lot of current and often are not fully inserted or they heat up and come loose. Sometimes to avoid doubt I solder them on.
- loose bolted connections on heavy internal cables and copper or aluminium busbars, at heatsinks, and on thick tracks on the PCBs, at the Euro socket, and the back of the front panel Dinse sockets.
- loose or poorly-seated plugs on the multi-wire harnesses between the PCBs
- any sign of blackened or burnt components.
Cudos to Eddie.
Allow caps to discharge.
Use volt meter to establish safe.
Use batteries or power supply at relay voltage.
Observe polarity and use to energize relay coil.
Should hear audible click when closing.
Mulltimeter on ohms across contact should tell you resistance of closed contact.
Should be practically zero ohms.
If high resistance or has any visable deformationsin relay case, replace.
Cheap as from aliexpress.
Allow caps to discharge.
Use volt meter to establish safe.
Use batteries or power supply at relay voltage.
Observe polarity and use to energize relay coil.
Should hear audible click when closing.
Mulltimeter on ohms across contact should tell you resistance of closed contact.
Should be practically zero ohms.
If high resistance or has any visable deformationsin relay case, replace.
Cheap as from aliexpress.
