Capacitor replacement

Hi,
I have an old miller AC welder, the model is M-180P. It
looks like de capacitor needs to be replace. The guys at Miller sent me a
part number and a pricy price ($150). Although I had asked for
specifications.
As equivalent parts could be purchase at a better price,
does anybody now of a way to get specifications for the capacitor?
Thanks
Soon a beginner.
Gilles
Reply to
Gilles Marchand
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Let us know what is printed on the old capacitor. Also more details on the model and serial number of the machine. I could not find the M-180P on Millers web site.
Reply to
Tm
Hi,
here is what extra information I have (given by Miller tech.): The part no for the capacitor on the M-180P is a 059417 and list price is $149.53 US. Hopefully this will help you have a nice day.
There may have been a part number on the capacitor itself but no info. on fharad, volts ... and it did say Miller.
Gilles
"Tm" a écrit dans le message de news: qPidnXG5C snipped-for-privacy@comcast.com...
Reply to
Gilles Marchand
Gilles, If you machine is an old AC buzz-box then it is likely that the capacitor is a power-factor correction capacitor. If so, it is likely connected to from one of the primary power leads to the transformer and the other end is connected to a separate lead coming from the transformer. This is how my Miller Thunderbolt 225 is shown but there are no values given and my welder doesn't have this option. If it is a power-factore correction capacitor, I would think that you should be able to run the welder without this capacitor. Maybe somebody on this forum can be more definite. It will draw a bit more current (but not cost you anymore money since the extra current is reactive) but that shouldn't be a problem. Billh
Reply to
billh
Can you let us know where the capacitor connects to in the welder? Since you say the welder is an AC welder, it sounds as if it is a power factor correction capacitor. Can you describe the capacitor? Oval metal case? Size?
You might take the cap by a heating and air conditioning place and see if they have an idea of what it is. $ 149.53 sounds like a very high price. The airconditioning place is likely to have some similar caps that they are throwing out. You might take some doughnuts 8-).
Dan
Reply to
dcaster
You might also take some photos of the capacitor both in and out of the circuit and post a link to them. We may be able to tell what type capacitor you have.
Reply to
Tm
Maybe we should start here. Why do you think this cap needs to be replaced? What is the machine doing? OR not doing?
remove 333 to email reply. Thanks, Randy
Reply to
Randy
Hi,
you are rigth the capacitor is power factor correcting model (m-180p; p-->power correcting ...) And yes what you describe for the wirering seems correct. The looks of the capacitor is metal all around and top. With some oil sipping out, maybe bpc? The overall dimension is approx. 3x4x5. I will try to take pictures of it for you. But Easter time will make me be away until wednesday.
Until then take care!
Gilles
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Reply to
Gilles Marchand
I have not used this welder, the seller showed me that it work. After getting the owners manual from Miller I opened it up for the annual check up. This is when I saw the capacitor sipping, lightly, oil. When I put the Ohmeter on the capacitor it has zero resistance. This makes me think that it is not in functionning condition.
Is this a correct conclusion?
Gilles
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Reply to
Gilles Marchand
If it is leaking and shows shorted, then you are correct.
Will te machine run when the capacitor is removed? If that is truly a PF correcting capacitor, then everything should work without it.
Tom
Reply to
Tm
Gilles, You must disconnect at least one terminal on the capacitor before you measure it. If you don't the ohmmeter will read the resistance of the transformer coil in parallel with the capacitor.
When testing the capacitor you may see the ohmmeter needle move a little when the capacitor first charges then settle back to a very high resistance reading (ideally infinity).
The dripping oil is not a good sign but if it is very little it might not be fatal.
Bill
Reply to
billh
A very large cap, like I expect this one is, may require a lengthy period before the it is charged up by the ohmmeter. Until that happens, current flows through the cap, and the ohmmeter senses low resistance.
How long did you measure it?
Gilles Marchand wrote:
Reply to
Gerald Cooper
Just happened to be reading an article on electric motors and the author said that if a capacitor is leaking a few drops of oil it probably is bad or words to that effect. Billh
Reply to
billh
Well you got me wondering if I did this rigth. Actualy, I removed de capacitor from the welder. It had no more wires to its connectors. Then I mesured it with the ohmmeter. With no resistance...
How does the correcting capacitor help in the welding process? Or what exactly is its purpose?
See you wednesday!
Gilles
"Gerald Cooper" a écrit dans le message de news: snipped-for-privacy@enews1.newsguy.com...
Reply to
Gilles Marchand
Gilles, If it had no connections to it other than the ohmmeter leads and it read 0 ohms (or a low value) the capacitor is shorted. If it is a power-factor correcting capacitor it does not play a part in the welding process. To put it very simply, the capacitor cancels out some of the effect of the big transformer in the box and permits the welder to use smaller supply wires and circuit breaker. Billh
Reply to
billh
When you say no resistance, do you mean that there is no change is indication on the meter when you connect it to the capacitor? I suspect that is what you mean, because you said you saw the welder work before you bought it. And if it had a really low resistance, it would have drawn a lot of current, heated up, and exploded.
Assuming that the capacitor is not shorted or open, you ought to be able to take it to a air conditioning shop and have them measure the capacitance. The meter you have might work, digital multimeters in the thirty dollar range now often have capacitange scales.
Dan
Reply to
dcaster
My dad had an old Forney welder that blew the capacitor and he took it to a shop. They disconnected the capacitor and it has worked just fine for the last 25 years. If I were you I'd disconnect it, put the cover back on, and use it.
Gilles Marchand wrote:
Reply to
hhrj
Check the cap again. When you first touch the meter to it you should grt some kind of reading in numbers. Eventually it should read as an open circuit. Try this a few times momentarily shorting the cap with a jumper wire after each test. A good oil cap should read infinite ohms eventually. If it checks good see if there is a capacity checking postion on the meter and see if you can measure it using this position. The cap maybe OK even if it is leaking a little oil. Soon it will be bad though. If you can measure the capacitance and tells the guys at the electrical supply place for what you are using it they can probably give you a replacement. If you cant measure it they can probably do this to as most decent meters have theis capability these days. This all hinges on the premis that it is not shorted or open ,just leaking a little oil. Baring this look at similarly rated welders that have a cap. Value should be close.Once you find the value I cant imagine it costing more than about $20.Also google checking a capacitor
Reply to
Jimmie
Well I found a shop to test the capacitor, I live in a small town..., it tested brooken. But he could not come up with a replacement part. So maybe I will put to use the adage: If it works do not fixe it!
Thanks for help.
"Gilles Marchand" a écrit dans le message de news: MQD%d.1092$ snipped-for-privacy@charlie.risq.qc.ca...
Reply to
Gilles Marchand
If you can determine the maximum voltage across the capacitor and give the size or a picture with a reference item such as a coin, it may be possible to estimate the ratings. Most of these oil filled AC caps scale with the size.
Tom
Reply to
Tm

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