EUR
en
Replaced a pump. The name plate said 0.3 hp 115v 9.7 amps. The .5 hp was closer to that amperage. Picked up a zoeller 1/2 hp at 9.8 amps which matches the motor chart. Located the .3 hp motor on line. Check specs on drop down. this is the motor I took out .3 hp at 9.7amps. Not the 7.2 amps like chart says for .3 hp. Why you think? And kinda messes up using chart hp and ampacity theory for replacing motors.
Given that the chart ((NEC) amps are based on the worst possible motor for that HP, I would not see it as any use as a replacement guide.
If it is 'special purpose' motor, not a general duty one, it may not need to follow the NEC values. This is how we get 40hp vacuum cleaners that draw 1A @120V.
In this case, it seems the OP has found a counterexample where the "full load actual" is greater than the "full load code".
Yet he has a motor that is worse efficiency then the worst possible in the NEC tables. This motor may not be in same classification as the motors in the NEC tables though, but is still a little surprising it draws more then the NEC tables. Maybe it is really a 1/2 hp design but for some reason only labeled 1/3 hp.
It's an oil-filled submersible motor. It takes a lot of power to churn oil; the 1/3-Hp rating might be _shaft_ HP - what's available to turn the pump.
That is what motor rating usually is - output shaft rating.
HP = torque (in ft lbs) x speed (in RPM) / 5250 (a mathematic constant). No mention of Amps. The charts in the NEC are intended to allow for the proper selection of conductors feeding motors of a given HP. They have nothing to do with designing motors and what the FLC will end up at. GENERALLY, the charts are higher than most motors but there are exceptions and if you come across one, like this, you use the higher value.
Bookmark
Daniel Féau processes personal data in order to optimise communication with our sales leads, our future clients and our established clients.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.