Electric Motor NEMA Frame Sizes Table

Electric Motors, Generators and Drives

The following are dimensional size charts for standard electric motor NEMA standard frames and configuration.

Standardized motor dimensions are established by the National Electrical Manufacturers Association (NEMA) - are tabulated below and apply to all base-mounted motors listed herein that carry a NEMA frame designation

Nema Frame

Note: All units are in inches. See bottom of webpage for more information on specifications.

NEMA
Frame
D*
2E
2F
BA
H (dia.)
N Min.
N
V Min.
Key Width
Key Thickness
Key Long
U
Dia.
42
2 5/8
3 1/2
1 11/16
2 1/16
9/32 slot
1 1/8
3/8
--
--
3/64 flat
--
3/8
48
3
4 1/4
2 3/4
2 1/2
11/32 slot
1 1/2
1/2
--
--
3/64 flat
--
1/2
48H
3
4 1/4
4 3/4
2 1/2
11/32 slot
1 1/2
1/2
--
--
3/64 flat
--
1/2
56
3 1/2
4 7/8
3
2 3/4
11/32 slot
1 7/8@
5/8@
--
3/16@
3/16@
1 3/8@
5/8
56H
3 1/2
4 7/8
3&5@@
2 3/4
11/32 slot
1 7/8@
5/8@
--
3/16@
3/16@
1 3/8@
5/8
56HZ
3 1/2
**
**
**
**
2 1/4
7/8
2
3/16
3/16
1 3/8
5/8
66
4 1/8
5 7/8
5
3 1/8
13/32 slot
2 1/4
3/4
--
3/16
3/16
1 7/8
3/4
143T
3 1/2
5 1/2
4
2 1/4
11/32
2 1/4
7/8
2
3/16
3/16
1 3/8
7/8
145T
3 1/2
5 1/2
5
2 1/4
11/32
2 1/4
7/8
2
3/16
3/16
1 3/8
7/8
146AT
3 1/2
5 1/2
5 1/2
2 3/4
11/32
2 1/4
7/8
2
3/16
3/16
1 3/8
7/8
148AT
3 1/2
5 1/2
7
2 3/4
11/32
2 1/4
7/8
2
3/16
3/16
1 3/8
7/8
149AT
3 1/2
5 1/2
8
2 3/4
11/32
2 1/4
7/8
2
3/16
3/16
1 3/8
7/8
1412AT
3 1/2
5 1/2
11
2 3/4
11/32
2 1/4
7/8
2
3/16
3/16
1 3/8
7/8
182
4 1/2
7 1/2
4 1/2
2 3/4
13/32
2 1/4
7/8
2
3/16
3/16
1 3/8
7/8
184
4 1/2
7 1/2
5 1/2
2 3/4
13/32
2 1/4
7/8
2
3/16
3/16
1 3/8
7/8
182T
4 1/2
7 1/2
4 1/2
2 3/4
13/32
2 3/4
1 1/8
2 1/2
1/4
1/4
1 3/4
1 1/8
184T
4 1/2
7 1/2
5 1/2
2 3/4
13/32
2 3/4
1 1/8
2 1/2
1/4
1/4
1 3/4
1 1/8
182AT
4 1/2
7 1/2
4 1/2
2 3/4
13/32
2 1/4
1 1/8
2
1/4
1/4
1 3/8
1 1/8
L182ACY
4 1/2
7 1/2
4 1/2
2 3/4
13/32
2 1/4
7/8
2
3/16
3/16
1 3/8
7/8
182AT
4 1/2
7 1/2
4 1/2
2 3/4
13/32
2 1/4
1 1/8
2
1/4
1/4
1 3/8
1 1/8
186ACY
4 1/2
7 1/2
7
2 3/4
13/32
2 1/4
7/8
2
3/16
3/16
1 3/8
7/8
186AT
4 1/2
7 1/2
7
2 3/4
13/32
2 1/4
1 1/8
2
1/4
1/4
1 3/8
1 1/8
L186AT
4 1/2
7 1/2
7
2 3/4
13/32
2 1/4
1 1/8
2
1/4
1/4
1 3/8
1 1/8
189AT
4 1/2
7 1/2
10
2 3/4
13/32
2 1/4
1 1/8
2
1/4
1/4
1 3/8
1 1/8
203#
5
8
5 1/2
3 1/8
13/32
2 1/4
3/4
2
3/16
3/16
1 3/8
3/4
204#
5
8
6 1/2
3 1/8
13/32
2 1/4
3/4
2
3/16
3/16
1 3/8
3/4
213
5 1/4
8 1/2
5 1/2
3 1/2
13/32
3
1 1/8
2 3/4
1/4
1/4
2
1 1/8
215
5 1/4
8 1/2
7
3 1/2
13/32
3
1 1/8
2 3/4
1/4
1/4
2
1 1/8
213T
5 1/4
8 1/2
5 1/2
3 1/2
13/32
3 3/8
1 3/8
3 1/8
5/16
5/16
2 3/8
1 3/8
215T
5 1/4
8 1/2
7
3 1/2
13/32
3 3/8
1 3/8
3 1/8
5/16
5/16
2 3/8
1 3/8
219AT
5 1/4
8 1/2
11
3 1/2
13/32
2 3/4
1 3/8
2 1/2
5/16
5/16
1 3/4
1 3/8
2110AT
5 1/4
8 1/2
12 1/2
3 1/2
13/32
2 3/4
1 3/8
2 1/2
5/16
5/16
1 3/4
1 3/8
224#
5 1/2
9
6 3/4
3 1/2
13/32
3
1
2 3/4
1/4
1/4
2
1
225#
5 1/2
9
7 1/2
3 1/2
13/32
3
1
2 3/4
1/4
1/4
2
1
254#
6 1/4
10
8 1/4
4 1/4
21/32
3 3/8
1 1/8
3 1/8
1/4
1/4
2 3/8
1 1/8
254U
6 1/4
10
8 1/4
4 1/4
17/32
3 3/4
1 3/8
3 1/2
5/16
5/16
2 3/4
1 5/8
256U
6 1/4
10
10
4 1/4
17/32
3 3/4
1 3/8
3 1/2
5/16
5/16
2 3/4
1 3/8
254T
6 1/4
10
8 1/4
4 1/4
17/32
4
1 5/8
3 3/4
3/8
3/8
2 7/8
1 5/8
256T
6 1/4
10
10
4 1/4
17/32
4
1 5/8
3 3/4
3/8
3/8
2 7/8
1 5/8
284#
7
11
9 1/2
4 3/4
21/32
3 3/4
1 1/4
3 1/2
1/4
1/4
2 3/4
1 1/4
284U
7
11
9 1/2
4 3/4
17/32
4 7/8
1 5/8
4 5/8
3/8
3/8
3 3/4
1 5/8
286U
7
11
11
4 3/4
17/32
4 7/8
1 5/8
4 5/8
3/8
3/8
3 3/4
1 7/8
284T
7
11
9 1/2
4 3/4
17/32
4 5/8
1 7/8
4 3/8
1/2
1/2
3 1/4
1 7/8
286T
7
11
11
4 3/4
17/32
4 5/8
1 7/8
4 3/8
1/2
1/2
3 1/4
1 7/8
284TC
7
11
9 1/2
4 3/4
17/32
3 1/4
1 5/8
3
3/8
3/8
1 7/8
1 5/8
286TS
7
11
11
4 3/4
17/32
3 1/4
1 5/8
3
3/8
3/8
1 7/8
1 7/8
324#
8
12 1/2
10 1/2
5 1/4
21/32
4 7/8
1 5/8
4 5/8
3/8
3/8
3 3/4
1 5/8
326#
8
12 1/2
12 1/2
5 1/4
21/32
4 7/8
1 5/8
4 5/8
3/8
3/8
3 3/4
1 5/8
324U
8
12 1/2
10 1/2
5 1/4
21/32
5 5/8
1 7/8
5 3/8
1/2
1/2
4 1/4
1 7/8
326U
8
12 1/2
12
5 1/4
21/32
5 5/8
1 7/8
5 3/8
1/2
1/2
4 1/4
1 7/8
324T
8
12 1/2
10 1/2
5 1/4
21/32
5 1/4
2 1/8
5
1/2
1/2
3 7/8
2 1/8
326T
8
12 1/2
12
5 1/4
21/32
5 1/4
2 1/8
5
1/2
1/2
3 7/8
2 1/8
324TS
8
12 1/2
10 1/2
5 1/4
21/32
3 3/4$
1 7/8$
3 1/2$
1/2
1/2
2$
1 7/8
364#
9
14
11 1/4
5 7/8
21/32
5 5/8
1 7/8
5 3/8
1/2
1/2
4 1/4
1 7/8
364S#
9
14
11 1/4
5 7/8
21/32
3 1/4
1 5/8
3
3/8
3/8
1 7/8
1 5/8
365#
9
14
12 1/4
5 7/8
21/32
5 5/8
1 7/8
5 3/8
1/2
1/2
4 1/4
1 7/8
364U
9
14
11 1/4
5 7/8
21/32
6 3/8
2 1/8
6 1/8
1/2
1/2
5
2 1/8
365U
9
14
12 1/4
5 7/8
21/32
6 3/8
2 1/8
6 1/8
1/2
1/2
5
2 1/8
364T
9
14
11 1/4
5 7/8
21/32
5 7/8
2 3/8
5 7/8
5/8
5/8
4 1/4
2 1/8
365T
9
14
12 1/4
5 7/8
21/32
5 7/8
2 3/8
5 7/8
5/8
5/8
4 1/4
2 3/8
364TS
9
14
11 1/4
5 7/8
21/32
3 3/4$
1 7/8$
3 1/2$
1/2
1/2
2$
1 7/8
365TS
9
14
12 1/4
5 7/8
21/32
3 3/4$
1 7/8$
3 1/2$
1/2
1/2
2$
1 7/8
404T
10
16
12 1/4
6 5/8
13/16
7 1/4
2 7/8
7
3/4
3/4
5 5/8
2 7/8
405T
10
16
13 3/4
6 5/8
13/16
7 1/4
2 7/8
7
3/4
3/4
5 5/8
2 7/8
404TS
10
16
12 1/4
6 5/8
13/16
4 1/4$
2 1/8$
4$
1/2
1/2
2 3/4$
2 1/8
405TS
10
16
13 3/4
6 5/8
13/16
4 1/4$
2 1/8$
4$
1/2
1/2
2 3/4$
2 7/8
404U
10
16
12 1/4
6 5/8
13/16
7 1/8
2 3/8
6 7/8
5/8
5/8
5 1/2
2 3/8
405U
10
16
13 3/4
6 5/8
13/16
7 1/8
2 3/8
6 7/8
5/8
5/8
5 1/2
2 3/8
444T
11
18
14 1/2
7 1/2
13/16
8 1/2
3 3/8
8 1/4
7/8
7/8
6 7/8
3 3/8
445T
11
18
16 1/2
7 1/2
13/16
8 1/2
3 3/8
8 1/4
7/8
7/8
6 7/8
3 3/8
444TS
11
18
14 1/2
7 1/2
13/16
4 3/4$
2 3/8$
4 1/2$
5/8
5/8
3$
2 3/8
445TS
11
18
16 1/2
7 1/2
13/16
4 3/4$
2 3/8$
4 1/2$
5/8
5/8
3$
2 3/8
444U
11
18
14 1/2
7 1/2
13/16
8 5/8
2 7/8
8 3/8
3/4
3/4
7
2 7/8
445U
11
18
16 1/2
7 1/2
13/16
8 5/8
2 7/8
8 3/8
3/4
3/4
7
2 7/8
449T
11
18
25
7 1/2
13/16
8 1/2
3 3/8
8 1/4
7/8
7/8
6 7/8
3 3/8
449TS
11
18
25
7 1/2
13/16
4 3/4$
2 3/8$
4 1/2$
5/8
5/8
3$
2 3/8
  • * Dimension D will never be greater than the above values on rigid mount motors, but it may be less so that shims up to 1/32" thick (1/16" on 364U and 365U frames) may be required for certain machines.
  • @@ Motors designated 56H have two sets of 2F mounting holes--3" and 5".
  • $ Standard short shaft for direct-drive applications.
  • # Discontinued NEMA frame.
  • ** Base of 56HZ frame motors has holes and slots to match NEMA 56, 56H, 143T and 145T mounting dimensions.
  • @ Certain NEMA 56Z frame motors have 1/2" x 1 1/2" long shaft with 3/64" flat. These exceptions are noted in the General Catalog.
  • & Dimension "V" is shaft length available for coupling, pinion or pulley hub - this is a minimum value.

NEMA Shaft Standard Dimensions and Sizes given in inch units

Nema Shaft Dimensions

Nema Shaft
Keyseat
Dimensions
U
R
S
3/8
21/64
Flat
1/2
29/64
Flat
5/8
33/64
3/16
7/8
49/64
3/16
1 - 1/8
63/64
1/4
1 - 3/8
1-13/64
5/16
1 - 5/8
1-13/32
3/8
1 - 7/8
1-19/32
1/2
2 - 1/8
1-27/32
1/2
2 - 3/8
2-1/64
5/8
2 - 1/2
2-3/16
5/8
2 - 7/8
2-29/64
3/4
2 - 3/8
2-7/8
7/8
3 - 7/8
3-5/16
1

Related: NEMA Knockout and Clearance Hole Diameter Machine Terminal Boxes

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