SIP 215 Wire speed problems (surging)

[auto351]

I have a SIP 215 and over the past week the wire speed has started to surge at lower speeds (7 and lower) and high speed (10) its ok

Its about 10 years old and gets used once ever few months.

What I have done so far

checked the wire reel tension; OK
checked the aliment of the wire feed rollers; OK
checked tension on motor drive rollers; OK
Check liner removed inspected, cleaned with compressed air, re-installed as was OK

what else could I look at?

 

[rtbcomp]

If it's the motor that's surging the first thing I would check would be the motor speed potentiometer, it may be worn at the at the lower speed settings.

Easiest way is to replace it anyway for what it would cost.

 

[Wallace]

I recently stripped and serviced a wirefeed motor to find the grease on the reduction gears was like glue. A good wash and re-grease with moly-disulphide made a big difference to the feed quality.

 

[auto351]

inspected the motor and it was OK.
I will re-grease tomorrow, to eliminate that a a cause.

I recall the voltage from the transformer feeds the motor but its unfiltered DC ?
and as the power switch in turned up from 1 to 6 this voltage is sent to the motor ?
or is the motor drive via WPM ?

I don't think it it the POT. i used a digital meter its showed smooth reading (ohms) , while turning the speed control

 

[rtbcomp]

Usually the speed control feeds a voltage to a power transistor which in turn controls the current through the motor.

This is a SIP TopMig control

 

[auto351]

Wallace, you are correct.

Lubricated the motor worm gears and now its a lot better, only surging at speeds under 2 which will not effect me now.

I must have a bent drive sharft as I marked the roller and the roller slows down at the same point on each revolution, (ruling out an electrical issue?)

Can you get these internal parts or do you have to buy the complete motor drive?

Thanks guys


rtbComp thanks for the diagram.

 

[Wallace]

Does the drive roller have 0.6mm & 0.8mm grooves? If so, try swapping them over and see if the feed improves as the groove may have worn unevenly. It is also worth checking the tension roller is smooth and not out of round.

Weldequip has a few wire feed motors listed here, none look to be worm & wheel drive though.

Here is the feed motor I serviced with the glue for grease. Simple spur gears in this one, no worm and wheel arrangement.