I assume you are talking about 430.52. That just reflects the ratio between normal FLA and LRA. The high effeciency motors evidently have a lower FLA for a given LRA. It must be a very short LR time since the big difference is in the instant trip breaker column
Re: 110.14(C)(1)(a)(4)#98714 02/18/0512:24 AM02/18/0512:24 AM
11-16 Log #2308 NEC-P11 (430-7(A)(9)) Final Action: Accept Submitter: Vince Baclawski, National Electrical Manufacturers Association (NEMA) / Rep. NEMA Recommendation: Revise as shown below: (9) Design letter for design B, C, or D, [or E deleted] motors. Substantiation: The Design E motor standard was rescinded by NEMA in February 2000. All references to Design E motors have been removed from NEMA Standards Publication MG 1-1998 "Motors and Generators".
This was one of approximately two dozen Proposals, all with the same Substantiation
[This message has been edited by rbalex (edited 02-18-2005).]
Re: 110.14(C)(1)(a)(4)#98715 02/18/0510:08 AM02/18/0510:08 AM
The same question was asked in this forum earlier. The only change to the Section was the elimination of “Design E” motors.
“General Purpose” motors, or as UL refers to them, “motors in ordinary locations,” are not listed; however, if they are designed to NEMA MG-1, their terminals are already suitable for 75C, regardless of the hp.
“Explosion-Proof” motors are listed, but are also generally NEMA Design B, C or D, so they also have terminals that are automatically rated at 75C no matter what hp.
I know that the deletion of the E design was the only change, but as far as my other question, since the terminals are 75 deg and marked, why is it necessary to include this wording in 110.14(C)(1)(a)(4)?
I'm just nitpicking, but it seems as though it is a waste of ink.
The motor terminals aren't required to be marked (they usually aren't) and the motors themselves aren’t listed; but, if the motor nameplate indicates they are NEMA Design B, C or D, the terminals are suitable for the full ampacity of conductors rated 75C or less.