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Motor starting switch

pain in the tail, my FAIP H150 electric power washer died. The motor starting capacitor went (oozed out the side of plastic shell). Replaced it with a similarly rated phenolic case starting cap but noticed it's getting very warm. More than likely the motor centrifugal switch is stuck closed. It is a TEFC motor so getting to the switch is a major pain. Not to mention that I don't see a replacement part listed anywhere.

As a test, I started the motor and then pulled a lead from the starting capacitor. It sparked, showing that there was current flowing. So, either this is a permanent split capacitor motor (unlikely) or the centrifugal switch has failed shorted.

Now looking for a simple electronic or magnetic replacement. Has anybody had any success with a similar replacement? My first thought was the starting relay commonly used in refrigerators and air conditioners. It has a current sensing relay coil in series with the run winding. Initially when power is applied, the rotor is stationary and the run winding current is high. This closes the contacts and applies power to the start winding (usually no capacitor used on this) and motor starts. When the motor is up to speed, the start current diminishes and the relay drops out, removing power from the start winding.

Thank you as always - Oppie

Reply to
Oppie
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How about a manual switch?

--

John Larkin                  Highland Technology Inc 
www.highlandtechnology.com   jlarkin at highlandtechnology dot com    

Precision electronic instrumentation 
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Reply to
John Larkin

Correction - it is FAIP model H120. That's what I get for doing something from memory at my age...

Reply to
Oppie

That means it works fine for you, but when your brother-in-law borrows it the thing comes back broken.

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Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com
Reply to
Tim Wescott

Not sure if they still are around but there used to be a solid state job (Probably a brimistor or such). You just wired it in series with the start winding and it went open in a short period of current flow.

Reply to
Rheilly Phoull

Maybe there's no switch. If so, you need a run capacitor rather than a start capacitor. Start capacitors are aluminum electrolytic while run capacitors are plastic film. Electrolytic capacitors produce gases at high currents and they'll explode without a long resting period.

Reply to
Kevin McMurtrie

I have seen those Bimetallic PTCs? in the little cheap fridges. They usually fail after a few years. But they have the desired mode of operation.

Cheers

Reply to
Martin Riddle

Yes. I'd sooner put in a 1 second time delay relay that opens the start circuit after the time delay.

Reply to
Oppie

Chuckle... I repaired the next door neighbor's refrigerator this August. One horrible time of year (in northern hemisphere) for it to die. It had a PTC in the starting circuit in series with the start capacitor. A bimetal overload switch would open the line feed when there was a fault or short cycle (where the compressor tries to restart under load). The PTC failed and burnt up rather dramatically! New starting module and capacitor from allappliancepros.com plus overnight shipping for $105 and neighbor was very happy to have it working again. Now he knows to vacuum the condensing coils once a year as the failure was largely due to them being totally clogged.

Reply to
Oppie

Duly noted. Thank you for the explanation. I was not aware of the difference. Trying to confirm whether it has a centrifugal switch and making the appropriate choice.

I did run the motor albeit without water pressurization loading. After motor was to speed, opened the capacitor circuit. There was no loss of speed when the capacitor was opened. I should repeat the test with hydrostatic load. The motor is a Nord and must have been a custom for FAIP. I haven't been able to get an answer from FAIP or whomever purchased them.

Regards - Oppie

Reply to
Oppie

That model uses an 80MFD 250VAC capacitor which is within the realm of a PS C motor value, there is no centrifugal switch or any other kind of start wi nding cutout, the start winding remains in the circuit permanently. Just sp end the $22 on FAIP part no. MECO61695 and be done with it.

Reply to
bloggs.fredbloggs.fred

A run cap of the same value, if I remember right, is significantly larger.

And if there is a start switch that does not open I would expect the start winding would overheat and fail. If there is a start switch and it is not opening the previous failed start cap may have protected the winding.

Reply to
bud--

The new thing is called a "Stearns Sinpac" switch. You may be able to get them from Grainger or McMaster-Carr. It is an electronic replacement for the potential relay used in larger hermetic compressors, as well as the older thermal starting control on small refrigerators. Just Google "sinpac switch" and you'll get the manufacturer's main page on this device, then you can dig for a local distributor of them.

Jon

Reply to
Jon Elson

Absolutely wrong technology for a high frequency ON/OFF cycle app like a pressure washer. His motor is a PSC anyway.

Reply to
bloggs.fredbloggs.fred

Thanks for the reality check! Thought I could get a grainger part similarly rated (of course "similarly rated" was open to conjecture). So, I spent $16 on the grainger cap but didn't have to pay for shipping...

My original thought was as Bud noted, the capacitor failed because the starting switch was stuck closed. I've had lots of motors with starting switches fail stuck and you can hear the difference when the start wining is energized. Leave it on too long and the start winding fries. That happened on one of our lathes. The operator thought Gee this motor's got more balls today and I can take bigger cuts... right up to the point where the motor smoked (found that since it was 'nuisance tripping' he had upped the current trip level). Since then, I've been trying to use a better current sense with something like a Siemens 48ATD1S00 to replace the OEM current relay.

Reply to
Oppie

Don't most pressure washers just let the motor run, and limit pressure with a relief valve? Or is that last decade's technology? Yes, of course, if it is PSC, then no starting control is needed. I had to trust the OP's description of the motor, which apparently was wrong.

Jon

Reply to
Jon Elson

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Some do and some don't. Some have a pressure actuated switch that cuts powe r to the motor whether the operator is holding the power switch (usually a momentary) ON or not (Karcher), some don't. Regardless, the operator will b e constantly turning the thing ON and OFF in normal use too. So thermal cut outs are not used here. And yes, most of them use bypass relief pressure re gulators.

Reply to
bloggs.fredbloggs.fred

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You can find the exploded parts diagram and part number list for all the FA IP stuff all over the web. There is no centrifugal switch, no potential rel ay, no nothing to cut the start winding out. The ON/OFF switch, Swiss made by DiSA, has the thermal protection, a M1630FV 12.5A T1, means a 12.5A fast thermal cutout, two pole single throw ( looks like one ea for run and star t windings ), spring loaded momentary. There is more to the cap than just r ating, it has a form factor and a grommet to waterproof the fast-on connect ion. If you don't have a waterproof fit, anything could happen.

Reply to
bloggs.fredbloggs.fred

Haven't found much for the H120 on the web. Even the FAIP-NA

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site doesn't have it. I erroneously referenced a H150 as that was the only one for which a user manual could be found. I think I found something similar in a Husky P1600

Reply to
Oppie

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