Complex Imaginary Test 1 Problem 4

[BamaBino]

The problem states:

A code "Design C" type maximum locked-rotor current for a 3-phase squirrel-cage induction motor rated 15hp, 230V is?

I used T430.7B to get 150A.

The solution used Table430.251B (for Selection of Disconnecting Means) to get 232A.

Isn't my solution the correct answer to the question that was asked?

 

[DK PE]

I don't have my code book handy but a quick internet search gave me 232A and referenced NEMA Standards MG 1-12.35. I'll try to search later.

I looked here but am not familiar or do I endorse with their work. Just happened to find it.
/>http://www.joliettech.com/max_locked_rotor_currents.htm

 

[ElecPwrPEOct11]

I believe the difference is in the word "Design C". This is an immediate clue to use table 430.251. If the problem said "Code C" you'd use 430.7. The problem could be worded better.

 

[knd107]

+1 for "Design" in lieu of "Code".

I guess they could have mentioned it was for "Max Locked-Rotor current for the selection of disconnecting means and controllers ..."