Relay Pickup dropout ratings question

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wirenut1980

wirenut1980

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Plainfield, IN
Hello, I have an Omron LY4 24 Vac relay. I looked up the specs and it lists the pickup voltage at 80% of nominal Voltage maximum, and the dropout voltage at 30% of nominal voltage minimum. I have a relay that failed and I believe it recieved approximately 60% of nominal voltage for approximately 70 minutes.

My question is: would 60% voltage cause chattering of the relay and cause it to fail? I am not sure what the ratings mean when they throw in maximum and minimum?

Thanks!:smile:
 
I'm guessing but I don't mind talking about it

60% probably won't pull in the armature. that being said ( and assuming it's true) the magnetic circuit is not complete and the inductive reactance of the coil remains low allowing the higer pull in current to persist and (just might) overheat the coil causing damage.

My experince with chatter is usually worn and or misaligned contacts or piviot on the armature and yes even broken pole shading. Carbon deposits on the contacts cause issues also.

Just some random thoughts.
 
=cpal;1051314]I'm guessing but I don't mind talking about it

60% probably won't pull in the armature. that being said ( and assuming it's true) the magnetic circuit is not complete and the inductive reactance of the coil remains low allowing the higher pull in current to persist and (just might) overheat the coil causing damage. .
Click to expand...

I'd agree, gotta be some online clarification on this I would think.

My experience with chatter is usually worn and or misaligned contacts or pivot on the armature and yes even broken pole shading. Carbon deposits on the contacts cause issues also.
Click to expand...

Excessive rust, had a bad dent result in excessive noise, also AC on a DC coil.
 
wirenut1980 said:
Hello, I have an Omron LY4 24 Vac relay. I looked up the specs and it lists the pickup voltage at 80% of nominal Voltage maximum, and the dropout voltage at 30% of nominal voltage minimum. I have a relay that failed and I believe it received approximately 60% of nominal voltage for approximately 70 minutes.

My question is: would 60% voltage cause chattering of the relay and cause it to fail? I am not sure what the ratings mean when they throw in maximum and minimum?

Thanks!:smile:
Click to expand...

It means the relay is guaranteed to pick-up by the time the voltage reaches 19.2 volts or greater (in your example). It might pick up at a lessor value than this but it is guaranteed to be energized by that value.

On turn off it is guaranteed to drop-out with anything less than 7.2V (in your example). Again it might drop-out at a higher voltage but is guaranteed
to drop out by the time it reaches 7.2v.

The area between 7.2V and 19.2V is a "grey area".

Your 60% value is in the grey area so it is unknown what would happen there.
In that range it could certainly chatter.
I do not know for sure but I imagine if left in that state long enough that it would degrade the relay.
 
cpal said:
I'm guessing but I don't mind talking about it

60% probably won't pull in the armature. that being said ( and assuming it's true) the magnetic circuit is not complete and the inductive reactance of the coil remains low allowing the higer pull in current to persist and (just might) overheat the coil causing damage.
Click to expand...

I think there is another word than guessing, when based on scientific understanding, one predicts an outcome without having either experienced it or proven it by testing. That is actually what happens trying to start a three-phase motor with one phase missing.
 
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