Calculate contactor capacity for AC22

Reloadron

Joined Jan 15, 2015
7,501
A contactor is efficient if it is a latching type contactor. The motor starting contactors used in medium voltage motor control are usually held closed by an operating coil, which is energized to close the contactor. When the coil is deenergized, the contactor opens. Since the contactor's coils is usually energized from a control power transformer connected to the primary circuit of the starter, this design provides automatic undervoltage protection for the motor. Yes, the coil is normally energized but even then the coil is a low current draw,

Its for distribution change over switch, about 80% is resistive (mostly server equipments, running for 24/7), another is moderately and highly inductive (water pump, bench drill, air conditioner, ...)
So it's a distribution changeover switch. I also believe all of this has been gone over before. It's like a Deja Vue. You do not need a motor or constantly energized coil.

Ron
 
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