relay clatter

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=55879
Printed Date: April 24, 2024 at 6:08 PM

Topic: relay clatter

Posted By: puginfo
Subject: relay clatter
Date Posted: May 17, 2005 at 1:59 AM

>>> hi all, i use a vacuum sensor running of the intake manifold to cutoff the aircon compressor when i drive hard. the problem i have is, the sensor is very sensitive to vacuum variations thus the output voltage swings at certain points of the accellerator. this voltage variation in turn causes the a/c cutoff relay to clatter. i think the alternator has a hard time as well because the relay clatter causes intermittent load. would there be a simple solution just to latch or hold the relay 'ON' for some specified period of time?

thks and cheers

Replies:

Posted By: hotwaterwizard
Date Posted: May 17, 2005 at 8:59 PM

Just put a 1000uf capacitor across the relay coils to absorb the surge.

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: puginfo
Date Posted: May 17, 2005 at 10:45 PM

>>> thks for the input John. how long - approx. would the 1000uF be able to latch the relay?

Posted By: hotwaterwizard
Date Posted: May 18, 2005 at 11:28 PM

no it would stop the clatter.

If you want to latch a relay you can with this circuit.

posted_image

To unlatch it just cut the power to it.

Or you could latch and ynlatch with switches like this Diagram.
posted_image

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !