locked rotor current

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locked rotor current

Can somebody please help me determine the locked rotor current - on a motor. thks Its aquestion asked of me applying for a new main service. :smile:
 
It's generally about 600% of the FLC. You can compare the two by looking at tables 430.247-430.251(B).
 
johnone said:
Can somebody please help me determine the locked rotor current - on a motor. thks Its aquestion asked of me applying for a new main service. :smile:
Click to expand...

Is this for fire pumps? Or for general service calculations?
 
general service calculations, requested on a sheet from the service provider in this case DWP... They also want the KVA on a 40a 240v hvac unit?
 
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When you first start a motor, current will be flowing and the rotor will not yet be moving. The current present at that moment is as high as the current will ever get (presuming there is no failure in the motor, of that you don?t try to instantly reverse the direction of rotation). If the rotor were to have been jammed, so that it could not rotate, then that max current would continue to flow forever (or until something broke or until an overcurrent device tripped). That is the origin of the phrase ?locked rotor current.?
 
johnone said:
general service calculations, requested on a sheet from the service provider in this case DWP... They also want the KVA on a 40a 240v hvac unit?
Click to expand...
If I am not mistaken it it would be 9.6 kVA

If I am wrong someone yell at me ;)
Just a student after all...
 
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