3.7 hp compressor motor no NEC FLA listed

[Jpflex]

When trying to size a feeder/ branch circuit for a 3.7 horsepower, single phase compressor at 230 volts

The NEC does not have a listing for 3.7 hp motor under its table for single phase motors. How then are you to size the feeder to 125% of the motor full load current according to NEC table when such a horsepower isn’t listed?

Or does this fall under appliance rules?

 

[Jpflex]

Motor nameplate

 

[ptonsparky]

Use the FLA on label.
Compressor HP values such as your 3.7 mean next to nothing. Marketing.

 

[hbiss]

That's not a 3.7HP if it doesn't say so on the motor.

Just use 15.7A off the name plate.

-Hal

 

[augie47]

Surprised it didn't come cord & plug. The HP rating you see is a sales gimmick...ignore that and follow hbliss's advice

 

[charlie b]

You could simply use the tabulated value for a 4 HP motor (if one appears in the table - I don't have my code book handy).

 

[Jpflex]

That's not a 3.7HP if it doesn't say so on the motor.

Just use 15.7A off the name plate.

-Hal

It’s interesting that the motor nameplate left the horsepower rating out

 

[don_resqcapt19]

It’s interesting that the motor nameplate left the horsepower rating out

Very typical for special purpose motors used for equipment when the manufacturer uses a fictitious horse power for marketing purposes...they use something like peak horsepower or a horsepower calculated from the inrush current. However that does not appear to be the case here with a nameplate current of 15.7 amps and Table 430.148 shows 17 amps for a 3 hp motor at 230 volts. The numbers in the table are very conservative so it is probably possible to build a 3.7hp motor with a full load current of 15.7.

 

[Jraef]

It’s interesting that the motor nameplate left the horsepower rating out

They don't like to create a conflict with their marketing department...
Compressor "HP" to the marketing department is a gimmick... They "calculate" that marketing value based on momentary torque capability.