locked rotor amperage

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jeff barnes

Member
Location
jacksonville
the name tag on a compressor lists the voltage and locked rotor amperage but not the F.L.A.. is there a formula to calculate the F.L.A. with the given values of 95.4 locked rotor amps and 208v 1ph?

jeff
 

bdarnell

Senior Member
Location
Indianapolis, IN
Occupation
Retired Engineer
Locked rotor (inrush) could be anywhere from 300% to 600% of FLA. Is part of the nameplate missing, or is this an old motor ? Can't say as I've ever seen a motor with LRA only.

Could you use Table 430.148 in your application ?
 

templdl

Senior Member
Location
Wisconsin
You've omitted telling use what exactly has been included on the nameplace. Because the LRA is so low compressor manufacture often omits a lot of namelpate info and markets the entire compressor assembly by labeling the horsepower on a part other than the motor. The may mark an 'SP' in place of an actual horse power on the motor name plate but I am surprized that there is not FLA marked.
These manufactures play games with the HP and there appears to by no standard in doing so, sort of like it's house rules, that is their own rules. For some reason they have gotten around the necessity of having to use NEMA ratings of their nameplate.
 
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