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Sizing for Motor Loads Softstarter and Protective Device

Sizing for Motor Loads Softstarter and Protective Device

Sizing for Motor Loads Softstarter and Protective Device

(OP)
Please help me on how to size / calculate for the required rating of the softstarter and protective device for a certain motor load. Thank you in advance.

RE: Sizing for Motor Loads Softstarter and Protective Device

First off it probably depends on the relevant code, which you haven't stated.  

RE: Sizing for Motor Loads Softstarter and Protective Device

(OP)
thanks for the feedback.

i.e:

motor specs / Source:
700 HP, V = 4160, 3 phase, 60 Hz

RE: Sizing for Motor Loads Softstarter and Protective Device

No, i.e. where in the world are you?  What standards and codes apply?

RE: Sizing for Motor Loads Softstarter and Protective Device

4160V 60Hz would imply the US, Canada or Mexico, maybe other South American countries like Chile that get a lot of their equipment from Canada and the US.

Assuming someone has properly sized the motor, you size the soft starter for the motor you will connect to it. I don't see the issue here. 700HP motor, 700HP starter.

Protective device? Do you mean the fuses or circuit breaker? Generally you will not have much of a choice, when you buy the soft starter, the devices inside will have been coordinated with specific fuses and you usually cannot deviate from those without violating the starter design. this is a discussion you need to have with the soft starter mfrs.

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