I have a question about a capacitor i have a 110 mig welder that i need to install a spool gun for alum weldind so they show using a 3 way switch power center top spool bottom mig gun in the power it shows a capacitor in inch line which I thought would stop surges ir goes from ac to a dc motor and it not letting any power thru can i have to big of a voltage its 500v or is the capacitor not allowing dc to pass any help would be nice John

My (possibly crude) attempt to parse the above:

I have a question about a capacitor.
I have a 110-volt MIG welder for which I need to install a spool gun for alum welding.
They show using a 3-way switch: center position is power, top is spool, bottom is MIG gun.
In the power position it shows a capacitor in line, which I thought would stop surges.
It goes from AC to a DC motor and is not letting any power thru.
Do I have too big of a voltage (capacitor is rated at 500v) or is the capacitor not allowing dc to pass.

If this is correct, the answers may be as follows:

No, the high voltage rating of the capacitor should be no problem.
Yes, a capacitor passes AC but blocks DC.

Other then a capacitor what would block a surge John or could I be wiring it wrong I put it inline one on each side I did it with a extension cord and a dc hook up nothing passes am I hooking it up wrong John

Who’s John?

Capacitors are usually used in parallel to filter off surges on DC stuff.

An inductor (coil) can be used in series to block surges (again, on DC), but aren’t used very often these days due to metal costs.

Capacitors will pass AC, but they have a certain amount of reactance to them and will drop the incoming voltage as well as a result. You generally don’t just shove random capacitors inline onto AC circuits to block surges.

Maybe you’re just not explaining things well, but from what you’ve posted it seems to me like you need to find someone with better electrical skills to do this for you. I’m picturing a lot of smoke and someone getting hurt before all of this is done.

I have a friend named John. That probably doesn’t help much.

A capacitor in series will pass AC and block DC.

500 volts is not too “big” for a 110 volt AC use. Usualy, capacitor “size” is referred to in microfarads, and they’re rated for however many volts.

I’m just not understanding the use - it sounds like there’s a switch being used to pick between welding wire feed or the welding gun, which makes no sense for MIG.

Can you tell us the make and model of the welder and where you’re getting the info on switches and capacitors?

Try Weldingweb and sentences.

A welding voltage is usually less than 50V, sometimes a lot less. You want lots of Mfd’s if this is meant to be some type of weld voltage filter or smoothing. Look at thumper stereo caps or welder-specific caps.

If you can post some reference to what you’re trying to do we could help.