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NEMA Code Letters for AC Motors

NEMA Code Letters for Locked-Rotor KVA
The letter designations for locked-rotor kVA per horsepower as measured at full voltage and rated frequency are as follows.

Letter
Designation
KVA per
Horsepower*
A
B
C
0.0 – 3.15
3.15 – 3.55
3.55 – 4.0
D
E
F
G
4.0 – 4.5
4.5 – 5.0
5.0 – 5.6
5.6 – 6.3
H
J
6.3 – 7.1
7.1 – 8.0
K
L
M
8.0 – 9.0
9.0 – 10.0
10.0 – 11.2
N
P
R
S
11.2 – 12.5
12.5 – 14.0
14.0 – 16.0
16.0 – 18.0
T
U
V
18.0 – 20.0
20.0 – 22.4
22.4 – & up

*Locked kVA per horsepower range includes the lower figure up to, but not including, the higher figure. For example, 3.14 is designated by letter A and 3.15 by letter B.
Reference: NEMA Standards MG 1 – 10.37.2.

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Code Letters Usually Applied to Ratings of Motors Normally Started on Full Voltage

Code Letters 

F G H J K L

Horse-
power

3-phase 15 up 10 – 7� 5 3 2 – 1� 1
1-phase – – – 5 3 2 – 1� 1 – �

Starting KVA per Horsepower for Single-Phase Motors

Starting KVA per hp =

Volts x Locked-Rotor Amps
1000 x hp

1 for 1 �
1.732 for 3 �

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