ac clutch relay

DAK dak at
Tue Jul 2 22:36:55 EDT 2002

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Bernie, I thought the flyback diode was on the coil side of the relay?
It shorts the pulse when the magnetic field on the coil collapses (as
the relay is shut off). I know a cap on the output side acts as a filter
to dampen the high frequency energy created as the conacts arc (just
before closing, or just after opening). Granted, I'm no EE, but I was
headed that way in the 80's when computer science got my attention.
Surely, some type of small value cap couild handle the EMF generated
when that clutch coil de-engergizes. Perhaps a diode on that as well?


PS. Kevin, am I off base here?

Bernie Benz wrote:

>Bad suggestion IMO.  The inductive energy stored in the clutch coil can
>never be handled by wimppy ceramic capacitor!  Open up the AC relay and
>replace the supression diode, which you will find is either open, causing
>much radio noise upon deenergiding, or shorted, in which case the compressor
>will not cycle, but run all the time.
>>From: DAK <dak at>
>>Date: Mon, 01 Jul 2002 22:54:59 -0400
>>To: Vincenzo Basile <Bleaf1 at>
>>Cc: 200q20v at
>>Subject: Re: ac clutch relay
>>From what I remember about my electronics tinkering days... You can put
>>a small value capacitor across the contacts on the relay to quite that
>>spark. I think on the order or 10 micro Farad, ceramic capacitor. Easily
>>found at Radio Shack or your favorite electronics surplus store.
>>These capacitors are non-polar, so just connect one lead to one of the
>>switch terminals, the other lead to the other switch terminal on the
>>relay. You could get fancy and open the relay and solder it in place.
>>Vincenzo Basile wrote:
>>>This is a multi-part message in MIME format.
>>>[ Picked text/plain from multipart/alternative ]
>>>Hi list
>>>Just wondering has anyone had the problem of sqeaching in the radio when the
>>>heats on,and linked it to the ac clutch relay?what exactly has to be changed
>>>in that relay?I remember  I could buy sometype of resister from radio shack
>>>instead of getting a whole new relay, if anybody knows exactly what it is I
>>>need I would appreciate the help .thanks
>>>200q20v mailing list
>>>200q20v at
>>200q20v mailing list
>>200q20v at


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