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Motor Protection 51 Settings

Motor Protection 51 Settings

Motor Protection 51 Settings

(OP)
Hi,

How can we set motor 51 protections low set, high set or IDMT?

RE: Motor Protection 51 Settings

Use inverse time overcurrent for overload protection and an instantaneous overcurrent for short circuit protection. Set the curve to match the motor overload curve. Usually set pickup at 115%-125% of Full Load Amps (FLA) with the time dial adjusted to trip on Locked Rotor Current faster than the allowable hot stall time and slower than the motor/load's acceleration time.

Set instantaneous above the motor inrush current.

You will need the motor thermal limit curves to properly set the relay.

RE: Motor Protection 51 Settings

And check that the contactor can open on short-circuit current if it's ever called so to do.

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