Motor Starter

[Kobe85]

If I am using a soft starter on a large motor, do I still need to multiply the motors FLA x 1.25 and find a wire that can meet that ampacity?

Isn't the 1.25 multiplier supposed to cover the inrush current? So if I am using a soft starter, wouldn't it seem unnecessary?

Thanks.

 

[petersonra]

If I am using a soft starter on a large motor, do I still need to multiply the motors FLA x 1.25 and find a wire that can meet that ampacity?

Isn't the 1.25 multiplier supposed to cover the inrush current? So if I am using a soft starter, wouldn't it seem unnecessary?

Thanks.

The 1.25 multiplier has nothing to do with inrush. It covers the service factor.

In any case, the inrush of a motor started across the line is often 6X FLA of a running motor.

 

[ADub]

The 1.25 sounds like your continuous load multiplier. Service factor is shown on the nameplate and is usually 1.15-1.25. This multiplier is used to determine the thermal overload setting


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[ActionDave]

If I am using a soft starter on a large motor, do I still need to multiply the motors FLA x 1.25 and find a wire that can meet that ampacity?.....

Yup, you do.

 

[Kobe85]

Thanks guys. Learning as I go!