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From: John Popelish
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X-Mailer: Mozilla 4.7 [en] (Win98; U)
Subject: Re: Help with relays please.
Date: Thu, 26 Sep 2002 19:14:41 GMT
NNTP-Posting-Date: Thu, 26 Sep 2002 15:14:41 EDT
Martin Perry wrote:
> I have a truck winch that is controlled by a number of relays. The
> relays fail after a short period of time. There is nothing wrong with
> the winch motor. The 12 volt relays switch 12 volts at a peak current
> of about 400 amps. Would it be possible to replace each relay with a
> triac and a simple circuit? Any help would be appreciated.
> Thanks, Martin Perry
I doubt that it is cost effective to replace these relays with solid
state devices, but you might be able ot do it with big power mosfets.
In the mean time, you could parallel your motor with a heavy duty
transient voltage suppressor like a 1.5KE20CADICT from Digikey. It
costs less than a dollar, but clamps 200 amps while allowing the
voltage to go no higher than about 22 volts. This greatly reduces the
flash each time the relay opens so the contacts last longer.
Newark Electronics http://www.newark.com/catalog/ has some big DC
contactors made by Stancor. For instance, the 120 and 586 series have
a 100 amp continuous, 400 amp inrush rating that may be an upgrade for
your relay. The Stancor 586 series has a 200 amp continuous, 600 amp
inrush rating. I am pretty sure that this is beefier than your relay.
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