Motor Contactor

[jenkinscody]

I am selecting a contactor for my motor using Fuji. I need to know what amp rating to use. I have full load current, locked rotor current and no load current.

 

[jraef]

Motor kW (or HP) and since it is an IEC contactor, duty cycle. FLC used against the Max. Amp rating of the contactor can be deceiving in motor applications because of the inductive load switching duty, so look at the kW of your motor and select a contactor that has that kW rating or higher. Then for IEC contactors such as the Fuji, you must also consider how often it will be starting, under what conditions, and how long you want it to last. Fuji will provide you with charts to select from. If you use a NMA rated contactor, all of that is done for you and the contactor is sized based on one of the worst case scenarios, similar to AC-4 in the IEC charts.

No Load Current has no bearing in this decision, and LRC will already be factored into the motor kW rating.


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