Industrial electric motors have been available for nearly a century. In that time there have been a great many changes. One of the most obvious has been the ability to pack more horsepower in a smaller physical size. Another important achievement has been the standardization of motors by the National Electrical Manufacturers Association (NEMA).

A key part of motor interchangeability has been the standardization of frame sizes. This means that the same horsepower, speed, and enclosure will normally have the same frame size from different motor manufacturers. Thus, a motor from one manufacturer can be replaced with a similar motor from another company provided they are both in standard frame sizes.

NEMA Frame Dimensions


Frame SizeUDE2FV Min.
423/8"2-5/8"1-1/4"1-11/16"1-1/8"
481/2"3"2-1/8"2-3/8"1-1/2"
56
56H
5/8"3-1/2"2-7/16"3"
5"
1-7/8"
143T
145T
7/8"3-1/2"2-3/4"4"
5"
2-1/4"
182
184
182T
184T
7/8"
7/8"
1-1/8"
1-1/8"
4-1/2"3-3/4"4-1/2"
5-1/2"
4-1/2"
5-1/2"
2"
2"
2-1/2"
2-1/2"
213
215
213T
215T
1-1/8"
1-1/8"
1-3/8"
1-3/8"
5-1/4"4-1/4"5-1/2"
7"
5-1/2"
7"
2-3/4"
2-3/4"
3-1/8"
3-1/8"
254
254U
256U
254T
256T
1-1/8"
1-3/8"
1-3/8"
1-5/8"
1-5/8"
6-1/4"5"8-1/4"
8-1/4"
10"
8-1/4"
10"
3-1/8"
3-1/2"
3-1/2"
3-3/4"
3-3/4"
284
284U
286U
284T
286T
284TS
286TS
1-1/4"
1-5/8"
1-5/8"
1-7/8"
1-7/8"
1-5/8"
1-5/8"
7"5-1/2"9-1/2"
9-1/2"
11"
9-1/2"
11"
9-1/2"
11"
3-1/2"
4-5/8"
4-5/8"
4-5/8"
4-5/8"
3"
3"
324
326
324U
326U
324T
326T
324TS
326TS
1-5/8"
1-5/8"
1-7/8"
1-7/8"
2-1/8"
2-1/8"
1-7/8"
1-7/8"
8"6-1/4"10-1/2"
12"
10-1/2"
12"
10-1/2"
12"
10-1/2"
12"
4-5/8"
4-5/8"
5-3/8"
5-3/8"
5"
5"
3-1/2"
3-1/2"
364
365
364U
365U
364T
365T
364TS
365TS
1-7/8"
1-7/8"
2-1/8"
2-1/8"
2-3/8"
2-3/8"
1-7/8"
1-7/8"
9"7"11-1/4"
12-1/4"
11-1/4"
12-1/4"
11-1/4"
12-1/4"
11-1/4"
12-1/4"
5-3/8"
5-3/8"
6-1/8"
6-1/8"
5-5/8"
5-5/8"
3-1/2"
3-1/2"
404
405
404U
405U
404T
405T
404TS
405TS
2-1/8"
2-1/8"
2-3/8"
2-3/8"
2-7/8"
2-7/8"
2-1/8"
2-1/8"
10"8"12-1/4"
13-3/4"
12-1/4"
13-3/4"
12-1/4"
13-3/4"
12-1/4"
13-3/4"
6-1/8"
6-1/8"
6-7/8"
6-7/8"
7"
7"
4"
4"
444
445
444U
445U
444T
445T
447T
449T
444TS
445TS
447TS
449TS
2-3/8"
2-3/8"
2-7/8"
2-7/8"
3-3/8"
3-3/8"
3-3/8"
3-3/8"
2-3/8"
2-3/8"
2-3/8"
2-3/8"
11"9"14-1/2"
16-1/2"
14-1/2"
16-1/2"
14-1/2"
16-1/2"
20"
25"
14-1/2"
16-1/2"
20"
25"
6-7/8"
6-7/8"
8-3/8"
8-3/8"
8-1/4"
8-1/4"
8-1/4"
8-1/4"
4-1/2"
4-1/2"
4-1/2"
4-1/2"

Download our handy NEMA Motor Frame Chart.