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5 HP 230 volt 3 phase motor using nema plug/receptacle vs pin/sleeve

Entropy9

Plastic
Joined
Aug 5, 2020
Hubbell L15-20P is limited to 20 amps, and 3 hp. L15-30P is limited to 30 amps, and 3 hp (same hp as L15-20P). Therefore if I have a 5 hp, 230 volt, 16 amp motor, then I must use pin and sleeve connections only?

Hubbell (in their specification sheets) limits L15-30P to 3 hp. Cannot find Leviton, nor Pass and Seymor data sheets with any hp restrictions.

Can I disregard Hubbells hp restriction on hp, and ensure amps are below 30 on motor? Maybe the hp limit is related to motor startup surge?

Thanks in advance.
 
If starting the motor with a contactor and full inrush current is expected, then yes, pin and sleeve is your answer. If using a VFD, then a Hubbell twist lock is fine.
 
Motion guru, thanks.

Machine is Kearney and Trecker 2h-plain horizontal mill, with original motor, starter, and wiring (78 year old wiring should be replaced I suppose ).

RPC is WNY 10 hp, 230 volt, motor for this is shown (hopefully ).

With this design of milling machine, it is not started under load, so fewer startup amps, and L15-30 plug/receptacle I guess would be ok.

The Mills small starter (displayed above), I am not familiar with.

Thanks for your sage advice.
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A NEMA B motor will be roughly 3kVA / HP inrush at start unloaded minimum . . . could be as high as 3.5kVA

That motor says 10HP so figure 30kVA -> 30,000VA = 230V x (n)A x 1.73 -> (n)A = 30,000VA / 230V / 1.73 = ~75Amps inrush unloaded

If the motor is closer to 3.5kVA . . . then inrush = 3.5/3 x 75A = 88Amps
 
For the record there is a non-NEMA 50 amp twistlock sold by Hubbel. Very solid connector often used for shore power hookups.
 








 
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