Repair my Emglo AM78-HV4V air compressor

If you were quoted $50 for a capacitor, I'd seriously try to find another place to deal with - what exact value capacitor do you need? did you check local electronics supply/surplus houses (be sure to say it's a motor start capacitor) - the last one I bought (three days ago) was 600 uf at 220VAC for $12, generally lower capacitance values are less expensive.

Bill

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will iam_ b_ No ble at msn daught com

Hi Bill,

Don't have it in front of me any more. Sent it home with my brother. But, if memory serves me correctly it's 60uF, 360VAC. The repair shop quoted $50.00, the Emglo (DeWalt?) website quoted $43.00. Pretty pricey item, I guess.

Mike

There are many starting caps/run caps/start kits on ebay. Check out

7576085987, HVAC MOTOR START CAPACITOR NEW 53-64 mfd 330 VAC M. About $11 with shipping. I consider this price expensive, by the way. Your dealer, though, is trying to rob you blind. i

Mike, I know this is OLD, but did you ever find out how to get inside to the centrifugal switch? I have one w/the same symptoms and I don't wanna ruin a $50 cap if the switch is stuck closed.

josh fired this volley in news:d2023$53361f4a$43de0cc0$ snipped-for-privacy@news.flashnewsgroups.com:

You never said anything about checking the unloader valve. The Emglo compressors ALL have unloader valves (most compressors do), and the compressors don't have a hope of starting up with any residual pressure in the tank unless it's working.

LLoyd

Or -- assuming a single-phase induction motor -- the start cap could be blown, so it does not get that initial motion necessary for the induction to generate pole pieces in the right place to pull the motor round. (I didn't see the original posting -- could he be in my killfile somehow?)

Enjoy, DoN.

"DoN. Nichols" fired this volley in news: snipped-for-privacy@Katana.d-and-d.com:

He checked all that, Don. Then, just turning the motor over by HAND, it would start... that tells me it was dead-heading against pressure.

Lloyd

replying to Lloyd E. Sponenburgh , josh wrote: lol. the original question was also how to separate the motor from the pump to inspect the centrifugal switch. pump won't start up correctly with 0 psi.

please look:

the main shaft can't be pulled out either way that I can see. the fan has no apparent connection. it looks like it was put on and the end of the shaft was tooled somehow to keep it in place. if it was popped off, would it be conceivable to be put back on?

Looking at that (the downloaded PDF, not the reduced drawing visible on the page) it does not appear to even *have* a centrifugal switch. I see the cap (item 220, with associated mounting nut and lockwasher), and the stator, with what *looks* like four leads coming out, and no visible terminal block or anything of the sort, unless that is part of the "end cover" (item 235).

It is *possible* that this thing has a capacitor *run* motor instead of a capacitor *start* motor, so there would be *no* centrifugal switch. Look at the capacitor to see whether it has a full AC voltage rating or just a DC one. The photo of it is too low contrast and too small to read the ratings on the cap from here, but you have the actual cap to look at.

Is 236 (a nut) used to hold the end cover in place, or the fan?

There is also item 846, which is called a "repair kit", and which appears to have a couple of screws, a nut and a washer, or perhaps two sizes of nuts, and three wires (or are those wrinkles in the plastic bag?)

It might also be possible (if enough wires go into the pressure switch) that it closes all contacts and then releases some to take the task of a centrifugal switch.

Whatever it is, it is a weird device.

And it looks as though it is rather noisy when it *is* working.

Good Luck, Don.

Thank you Don I didn't even see the detailed pdf. There are a total of 8 leads coming from the motor: a ground at motor, 2 leads to the capacitor, 2 to a overload switch, and 3 head to pressure switch. One of those in pressure switch is ground.

The cap is 250v 60uf. Does that indicate it's a capacitor 'run' motor? I (for whatever reason) thought there would be another cap inside the end cover with the motor.

Nut-236 corresponds with bolt-230 which sandwiches the motor with the crankcase-221 and end cover.

Yeah, that's a great illustration ain't it! Not sure what those are.

How'd you know it was a noisy bugger? I guess I'll bite the bullet and order the cap and see how it performs. Thanks again Don. Josh

[ ... ]

O.K. Hard to tell from that whether there is a centrifugal switch hiding inside the housing -- but they sure don't list parts for one.

Hmm ... what HP for the motor? I think that may be closer to the value for a run cap instead of a start cap, but I'm not sure. Did the rating on the cap say 250 VDC or 250 VAC? If it is an AC rating, then it is likely a run cap -- and more expensive (and larger) than the typical motor start cap.

[ ... ]

:-)

Direct drive compressors Tend to be very noisy. And oil free, too?

I prefer belt drive oil wetted compressors -- even the small ones are relatively quiet. Still not silent, but less likely to make you throw something through the ceiling when they start up. :-)

No spare caps around the house to test it with? I guess that your house is not like mine. :-)

And no way to measure the capacitance of the cap? For a very coarse way, take an ohmmeter and see how long it takes to get to a certain reading when you reverse the probes. Compare it to a smaller voltage capacitor of the same nominal capacitance to see whether you're in the ballpark.

You're welcome.

Good Luck, DoN.