clarke 150en turbo mods, adding smoothing caps?

[pondy]

Few years back I got my first mig, clarke 150en turno. Paid £20 for it and it welds fine but the wire speed is eratic somtimes. I have added a dinze panel connector and a heavy duty earth cable, wire feed motor out of a portamig and a euro torch, small transformer to power a computer fan on the back of the pcb. Still having issues with the wire feed, pcb does not supply a stable voltage to the motor when welding so the pcb is being sent away and tested and have any changes made to it and am going to add a aux transformer to power the pcb like you do on the sip welders. After doing this I thought I might aswell upgrade a little more and add smoothing caps but have no idea what effects these have on the power output of the welder, read this may increase the min power making it harder to weld thin metals? How are these wired into the welder?

 

[shenion]

Aux transformer probably won't make much of a difference. The portamig motor is probably too much current for the PCB.

Smoothing caps on the supply will increase the minimum current and make the voltage vary more under load.

I'd suggest something small like 4700uf at at least 50V.

 

[pondy]

The voltage coming out the pcb to the motot is all over the place. A company called technical arc is helping me out and are going to check the operation of the pcb and see if it has the amparage to drive the larger motor. Was told a aux power supply to the pcb is the answer. Is the caps wired in between the rectifier and the torch assembly? Is adding a cap going to make a differance the to arc on a small machine?

 

[pondy]

also might aswell ask, when the wire speed is over 8 and i hold the trigger down the motor will turnj for around 30 seconds then the voltage to the motor stops for around 5 seconds then the voltage comes back and the motor turns again, another 30 seconds or so it will cut out again, this is only on the very high wire speed settings

 

[shenion]

If it is PWM control, it may be difficult to measure the voltage without a true RMS meter. Some Clarkes used a regulated voltage, others use similar to a light dimmer circuit (pulse width control.)

The caps go across the output of the large rectifier but before the reactor choke. They will improve the arc a bit, especially at lower power settings.

 

[pondy]

If it is PWM control, it may be difficult to measure the voltage without a true RMS meter. Some Clarkes used a regulated voltage, others use similar to a light dimmer circuit (pulse width control.)

The caps go across the output of the large rectifier but before the reactor choke. They will improve the arc a bit, especially at lower power settings.

i not sure if its pwm or not, electrics have never been a strong point for me. would you say for the price of a cap its worth doing this mod?

http://www.ebay.co.uk/itm/47000uF-5...108?pt=LH_DefaultDomain_3&hash=item1c2c69c75c

 

[shenion]

I'd look at 2000 to 5000uf @ 50 volts or higher. Low ESR or "Computer grade".

Anything larger and your minimum current goes up.

 

[pondy]

i thought you said 47000uf, just recheck, 2 many 0's!