Coil burning out

[anup]

Dear Patron,
I am facing a problem in EOT crane. The magnetic contactor coils are getting damage
frequently. Coil supply is 380V, 50Hz & coil resistance is 55 ohm. These contactors are
supplying to main hook motor & slipring resistance box i.e. the stator supply & rotor
supply.Contactors contact supply rating is 200A.
The ambient temperature is high, around 32 degree celcius.
How I can protect them.

Regards,
Anup

 

[Knobhead]

On a hoist drive I’d fit varistors across the coils.

 

[anup]

But what should be the varistor rating. The coil is designed for 380V,50Hz. plz reply.

 

[shanky887614]

But what should be the varistor rating. The coil is designed for 380V,50Hz. plz reply.

www.electronics-tutorials.ws/resistor/varistor.html

 

[Knobhead]

You may find this is more useful Varistor selection.