Capacitor replacement

I agree the most important thing to determine is the maximum voltage across the capacitor. If you have a voltmeter, you can just connect it
where the capacitor connects and turn the welder on. You don't need to do any welding while measuring.
Of course if you can see that the capacitor just connects across the AC line, you don't need to do any measuring. But I suspect that the capacitor may connect to a winding in the transformer and have a voltage on it that is higher than the line voltage.
Dan
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Yes, the wire does comes out from somewhere in the winding. Il will do that the next time I find 15 minutes. And I suppose a small jpeg could be included in the next post.
Gilles

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On Wed, 06 Apr 2005 12:23:00 GMT, "Gilles Marchand"

You really need to use the drop box for pictures.
The flash flare prevents seeing the poorly stamped lettering on the cap.
Take a piece of paper and a pencil and do a "rubbing" of the lettering and it may show the value.
Gunner
Rule #35 "That which does not kill you, has made a huge tactical error"
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What do you call the drop box for the picture?
There is not much to do with the marking on the capacitor. It says Miller mfg co, some number that looks like a part number. Internaly fuse. Not much to help get an equivalant.
Gilles

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On Thu, 07 Apr 2005 12:13:17 GMT, "Gilles Marchand"

Oy... <G>
go to www.metalworking.com and check out the drop box.
Plus its a fascinating place to browse other peoples work, welders, machine tools and whatnot.
Gunner

Rule #35 "That which does not kill you, has made a huge tactical error"
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replying to dcaster, Robert wrote:

I know this is an OLD post, but as it turns out, I have the same issue with another Miller Welder of the same vintage and family as the previous question. Mine is a Miller 225p, which is identical to his 180p but a slightly larger transformer, and it uses the same capacitor for power correction. I don't know for sure when this welder was manufactured, but considering the fan does not have oil caps, and the factured after my 1969 manual, and my guess is late 1960's or early 1970's. In doing research this is what I came up with:
Capacitor, Ppr Oil 30. Uf 460 Vac Part# MI059417.
The cheapest I have found a replacement Miller capacitor is $168 plus shipping, and the welder is not worth that investment, so....I have a couple of questions:
1. I can find inexpensive capacitors that have the 30 uF 460 VAC rating, although so far the only ones are HVAC run/start capactiors with an additional pole. Can I just use one of them and just the appropriate uF pole for my unit? They are less than $10...seems tooo good to be true.
2. When the suggestions above say "disconnect" the capacitor, does that literally mean disconnect it and tape off the leads, or do I jump them together?
3. I have not taken the one I have to be tested, but when I opened up the unit, it was heavily rusted. I didn't want to take a chance with all the vibration from the transformer of being "surprised" by it leaking, and so removed it and decided to take a wire brush lightly to the case so I could at least inspect it, paint it, and then know if it ever leaked. Of course, there was the likelihood that in taking the wire brush to the case that I might create a leak if the rust was too deep, and sure enough, I now have a couple of pinholes at the bottom. Only a couple of drops leaked, and if the capacitor tested OK I suppose I could just plug them with epoxy, but if I can purchase an inexpensive replacement it seems like that would be MUCH more prudent.
Thoughts?
Robert
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On Jun 1, 12:18pm, Robert

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First the capacitor is for power factor correction, right? So you can just remove the capacitor and use it without the power factor correction.
Second I personally would not bother with testing the capacitor. The oil in the capacitor is to prevent high voltage breakdown. So I would replace it.
Third when you disconnect the capacitor, tape the leads. Do not connect the leads together.
Fourth you want a oil filled capacitor. Grainger has some that are rated for 440 vac. I would not be concerned that they are rated for slightly less voltage than 460 volts.
Dan
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replying to snipped-for-privacy@krl.org , Robert wrote:

--
Thanks Dan! Yes the capacitor is for power factor correction.

As it turns out, I was just looking at the Grainger catalog, and sure enough
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