Contactor coil big inrush

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megloff11x

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A company that will remain anonymous substituted a discontinued contactor with their latest and greatest. The new model has inrush current that reminds me of that Japanese guy who wolfs down the hot dogs. I have four of them that draw a little over an amp total between them in steady state, but close to 30A when the button is pushed. The typical button set up in a start/stop loop has 10A contacts. I don't care if the ratings are based on steady state. I see welding in the future if I don't pilot this set up with another relay with a less demanding coil, but fat enough contacts to handle the 83ms duration surge.

I noticed the problem when the system tripped an overload protection circuit in the DC power supply providing the 24V. It never happened with the older model contactors. I had to get a bigger DC supply too.

Has anyone else had this issue, and how much ampacity did you make your pilot relay's contacts?

Matt
 
Coil Inrush Varies

Coil Inrush Varies

I recently looked at coil ratings and they are all over the place for similarly rated contactors. We ended up looking for a contactor with a coil inrush and holding current that was compatable with the control switch rating. Can you get replacement coils?
 
megloff11x said:
The new model has inrush current that reminds me of that Japanese guy who wolfs down the hot dogs. I have four of them that draw a little over an amp total between them in steady state, but close to 30A when the button is pushed.

I noticed the problem when the system tripped an overload protection circuit in the DC power supply providing the 24V. It never happened with the older model contactors. I had to get a bigger DC supply too.

Matt
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I've never heard of inrush on DC coils. Something doesn't fit here. With AC, I've never seen over about 10:1, ever, and that's measuring with an oscilloscope; most seem to be between 4 and 6:1.

George
 
A UL Listed "A600" pushbutton contact is rated for: 7200VA make, 720VA break, and 10A continuous with a 35%PF.

So at 120V it has been tested as 60A make and 6.0 break. If your inrush is only 30A you have a 2:1 safety factor.
 
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