# Induced voltage relay chatter



## wildleg (Apr 12, 2009)

mechanically held


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## telsa (May 22, 2015)

1) It's Edison obvious: go with DC. 

2) Install a capacitor to buffer the noise... which must be out of phase to produce the chatter. ( It's messing with the wave form as AC commutates. ) A correctly sized capacitor will pull the two into phase alignment. I can't tell you what that might be. 

A 'scope and a decade box of capacitors would do the trick.

3) Mechanically held relay.


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## splatz (May 23, 2015)

sparkie said:


> The problem we have is 20v ac induced voltage which causes relay to chatter- we have verified with two separate meters this is induced 20vac.


I am just curious, you've probably done all of this, but this is what I would do before I got creative...

* Double check all the specs of the relay, control and load voltage and ampacity. 

* See if the control power supply is adequate. 

* Make sure there's nothing whacked about the wire routing, bonding, or etc. generating this induced voltage. Maybe bench test the relay with a similar load and control power and see if it chatters. 

* Try another relay of the same make and model to see if the relay is defective. I'd think if the relay is properly designed, and the load and control are in spec, the induced current from the load should not overpower the control / coil. 

* Try another relay of a different make and model with suitable specs.


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## micromind (Aug 11, 2007)

I've solved this type of problem with a simple resistor across the coil. Just make sure that its watt rating is not exceeded.


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## Big John (May 23, 2010)

I agree a simple shunt rsistor in parallel with the coil will work. Just remember you're not sizing it based on ghost voltage, size it for the full control voltage the circuit will see when energized.

Out of curiosity, what's the VA on your relay coil? You may be able to just toss in a relay with a larger burden and this will solve itself.


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## just the cowboy (Sep 4, 2013)

*Light bulb*



Big John said:


> I agree a simple shunt rsistor in parallel with the coil will work. Just remember you're not sizing it based on ghost voltage, size it for the full control voltage the circuit will see when energized.
> 
> Out of curiosity, what's the VA on your relay coil? You may be able to just toss in a relay with a larger burden and this will solve itself.


Hang a light bulb on it if the extra relay don't work.


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## Frank Mc (Nov 7, 2010)

It sounds like to me there,s a solid state output driving the contactor which must have a snubber circuit onboard which is causing the chattering ..??

As others have suggested add some load to the same circuit and if thats the cause it should fix it...

Good Luck
Frank


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## buffalonymann (Dec 25, 2016)

Send me a schematic of what you have and I'll send you a solution


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