Reed Electric

Motor Frame Dimensions and Sizes by Horsepower and Speed

In the tables, you will see the 3 different times that these standardized Frame sizes were revised to take advantage of motor technology and materials improvements which basically allowed for a reduction in physical sizes of the motors for the same horsepower, speed, and enclosure.

As seen in our Knowledge base section, Size Matters. These tables will also help you determine the correct sizing of motors and frames.

TABLE 1 — OPEN DRIP-PROOF
THREE PHASE FRAME SIZES — GENERAL PURPOSE
RPM
NEMA
Program
HP


Orig.
3600
1952
Rerate

1964
Rerate


Orig.
1800
1952
Rerate

1964
Rerate


Orig.
1200
1952
Rerate

1964
Rerate


Orig.
900
1952
Rerate

1964
Rerate
1 203 182 143T 204 184 145T 225 213 182T
1.5 203 182 143T 204 184 145T 224 184 182T 254 213 184T
2 204 184 145T 224 184 145T 225 213 184T 254 215 213T
3 224 184 145T 225 213 182T 254 215 213T 284 254U 215T
5 225 213 182T 254 215 184T 284 254U 215T 324 256U 254T
7.5 254 215 184T 284 254U 213T 324 256U 254T 326 284U 256T
10 284 254U 213T 324 256U 215T 326 284U 256T 364 286U 284T
15 324 256U 215T 326 284U 254T 364 324U 284T 365 326U 286T
20 326 284U 254T 364 286U 256T 365 326U 286T 404 364U 324T
25 364S 286U 256T 364 324U 284T 404 364U 324T 405 365U 326T
30 364S 324US 284TS 365 326U 286T 405 365U 326T 444 404U 364T
40 365S 326US 286TS 404 364U 324T 444 404U 364T 445 405U 365T
50 404S 364US 324TS 405S 365US 326T 445 405U 365T 504 444U 404T
60 405S 365US 326TS 444S 404US 364T 504 444U 404T 505 445U 405T
75 444S 404US 364TS 445S 405US 365T 505 445U 405T 444T
100 445S 405US 365TS 504S 444US 404T 444T 445T
125 504S 444US 404TS 505S 445US 405T 445T
150 505S 445US 405TS 444T
200 444TS 445T
250 445TS
TABLE 2 — TOTALLY ENCLOSED FAN COOLED
THREE PHASE FRAME SIZES — GENERAL PURPOSE
RPM
NEMA
Program
HP


Orig.
3600
1952
Rerate

1964
Rerate


Orig.
1800
1952
Rerate

1964
Rerate


Orig.
1200
1952
Rerate

1964
Rerate


Orig.
900
1952
Rerate

1964
Rerate
1 203 182 143T 204 184 145T 225 213 182T
1.5 203 182 143T 204 184 145T 224 184 182T 254 213 184T
2 204 184 145T 224 184 145T 225 213 184T 254 215 213T
3 224 184 182T 225 213 182T 254 215 213T 284 254U 215T
5 225 213 184T 254 215 184T 284 254U 215T 324 256U 254T
7.5 254 215 213T 284 254U 213T 324 256U 254T 326 284U 256T
10 284 254U 215T 324 256U 215T 326 284U 256T 364 286U 284T
15 324 256U 254T 326 284U 254T 364 324U 284T 365 326U 286T
20 326 286U 256T 364 286U 256T 365 326U 286T 404 364U 324T
25 365S 324U 284TS 365 324U 284T 404 364U 324T 405 365U 326T
30 404S 326US 286TS 404 326U 286T 405 365U 326T 444 404U 364T
40 405S 364US 324TS 405 364U 324T 444 404U 364T 445 405U 365T
50 444S 365US 326TS 444S 365US 326T 445 405U 365T 504 444U 404T
60 445S 405US 364TS 445S 405US 364T 504 444U 404T 505 445U 405T
75 504S 444US 365TS 504S 444US 365T 505 445U 405T 444T
100 505S 445US 405TS 505S 445US 405T 444T 445T
125 444TS 444T 445T
150 445TS 445T



Motor Frame Dimensions

{gallery cols=5 height=125 width=125}blog_images/framesize_slides{/gallery}

NEMA
SHAFT
KEYSEAT NEMA
SHAFT
KEYSEAT
DIMENSIONS DIMENSIONS
(U) (R) (S) (U) (R) (S)
3/8 21/64 FLAT 1-7/8 1-19/32 1/2
1/2 29/64 FLAT 2-1/8 1-27/32 1/2
5/8 33/64 3/16 2-3/8 2-1/64 5/8
7/8 49/64 3/16 2-1/2 2-3/16 5/8
1-1/8 63/64 1/4 2-7/8 2-29/64 3/4
1-3/8 1-13/64 5/16 3-3/8 2-7/8 7/8
1-5/8 1-13/32 3/8 3-7/8 3-5/16 1
NEMA
FRAME
D E 2F H N O P U V AA AB AH AJ AK BA BB BD XO TAP
42 2-5/8 1-3/4 1-11/16 9/32
SLOT
1-1/2 5 4-11/16 3/8 1-1/8 3/8 4-1/32 1-5/16 3-3/4 3 2-1/16 1/8 4-5/8 1-9/16 1/4-20
48 3 2-1/8 2-3/4 11/32
SLOT
1-7/8 5-7/8 5-11/16 1/2 1-1/2 1/2 4-3/8 1-11/16 3-3/4 3 2-1/2 1/8 5-5/8 2-1/4 1/4-20
56
56H
3-1/2 2-7/16 3 11/32
SLOT
2-7/16
2-1/18
6-7/8 6-5/8 5/8 1-7/8 1/2 5 2-1/16 5-7/8 4-1/2 2-3/4 1/8 6-1/2 2-1/4 3/8-16
143T
145T
3-1/2 2-3/4 4
5
11/32 2-1/2 6-7/8 6-5/8 7/8 2-1/4 3/4 5-1/4 2-1/8 5-7/8 4-1/2 2-1/4 1/8 6-1/2 2-1/4 3/8-16
182
184
182T
184T
4-1/2

3-3/4

4-1/2
5-1/2
4-1/2
5-1/2
13/32

2-11/16
2-11/16
3-9/16
3-9/16
8-11/16

7-7/8

7/8
7/8
1-1/8
1-1/8
2-1/4
2-1/4
2-3/4
2-3/4
3/4 5-7/8 2-1/8
2-1/8
2-5/8
2-5/8
5-7/8
5-7/8
7-1/4
7-1/4
4-1/2
4-1/2
8-1/2
8-1/2
2-3/4 1/8
1/8
1/4
1/4
6-1/2
6-1/2
9
9
2-3/8 3/8-16
3/8-16
1/2-13
1/2-13
213
215
213T
215T
5-1/4

4-1/4

5-1/2
7
5-1/2
7
13/32

3-1/2
3-1/2
3-7/8
3-7/8
10-1/4

9-9/16

1-1/8
1-1/8
1-3/8
1-3/8
3
3
3-3/8
3-3/8
3/4

7-3/8

2-3/4
2-3/4
3-1/8
3-1/8
7-1/4

8-1/2

3-1/2

1/4

9

2-3/4

1/2-13

254U
256U
254T
256T
6-1/4

5

8-1/4
10
8-1/4
10
17/32

4-1/16
4-1/16
4-5/16
4-5/16
12-7/8

12-15/16

1-3/8
1-3/8
1-5/8
1-5/8
3-3/4
3-3/4
4
4
1

9-5/8

3-1/2
3-1/2
3-3/4
3-3/4
7-1/4

8-1/2

4-1/4

1/4

10

---

1/2-13

284U
286U
284T
286T
284TS
286TS
7

5-1/2

9-1/2
11
9-1/2
11
9-1/2
11
17/32

5-1/8
5-1/8
4-7/8
4-7/8
3-3/8
3-3/8
14-5/8

14-5/8

1-5/8
1-5/8
1-7/8
1-7/8
1-5/8
1-5/8
4-7/8
4-7/8
4-5/8
4-5/8
3-1/4
3-1/4
1-1/2

13-1/8

4-5/8
4-5/8
4-3/8
4-3/8
3
3
9

10-1/2

4-3/4

1/4

11-1/4

---

1/2-13

324U
326U
324T
326T
324TS
326TS
8 6-1/4 10-1/2
12
10-1/2
12
10-1/2
12
21/32 5-7/8
5-7/8
5-1/2
5-1/2
3-15/16
3-15/16
16-1/2 16-1/2 1-7/8
1-7/8
2-1/8
2-1/8
1-7/8
1-7/8
5-5/8
5-5/8
5-1/4
5-1/4
3-3/4
3-3/4
2 14-1/8 5-3/8
5-3/8
5
5
3-1/2
3-1/2
11 12-1/2 5-1/4 1/4 13-3/8 --- 5/8-11
364U
365U
364T
365T
364TS
365TS
9 7 11-1/4
12-1/4
11-1/4
12-1/4
11-1/4
12-1/4
21/32 6-3/4
6-3/4
6-1/4
6-1/4
4
4
18-1/2 18-1/4 2-1/8
2-1/8
2-3/8
2-3/8
1-7/8
1-7/8
6-3/8
6-3/8
5-7/8
5-7/8
3-3/4
3-3/4
2-1/2 15-1/16 6-1/8
6-1/8
5-5/8
5-5/8
3-1/2
3-1/2
11 12-1/2 5-7/8 1/4 13-3/8 --- 5/8-11
404U
405U
404T
405T
404TS
405TS
10

8

12-1/4
13-3/4
12-1/4
13-3/4
12-1/4
13-3/4
13/16

7-3/16
7-3/16
7-5/16
7-5/16
4-1/2
4-1/2
20-5/16

20-1/8

2-3/8
2-3/8
2-7/8
2-7/8
2-1/8
2-1/8
7-1/8
7-1/8
7-1/4
7-1/4
4-1/4
4-1/4
3

18

6-7/8
6-7/8
7
7
4
4
11

12-1/2

6-5/8

1/4

13-7/8

---

5/8-11

444U
445U
444T
445T
447T
449T
444TS
445TS
447TS
449TS
11

9

14-1/2
16-1/2
14-1/2
16-1/2
20
25
14-1/2
16-1/2
20
25
13/16

8-5/8
8-5/8
8-1/2
8-1/2
8-15/16
8-15/16
5-3/16
5-3/16
4-15/16
4-15/16
22-7/8
22-7/8
22-7/8
22-7/8
22-15/16
22-15/16
22-7/8
22-7/8
22-15/16
22-15/16
22-3/8
22-3/8
22-3/8
22-3/8
23-3/4
23-3/4
22-3/8
22-3/8
23-3/4
23-3/4
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
8-5/8
8-5/8
8-1/2
8-1/2
8-1/2
8-1/2
4-3/4
4-3/4
4-3/4
4-3/4




3



4NPT
4NPT
19-9/16
19-9/16
19-9/16
19-9/16
21-11/16
21-11/16
19-9/16
19-9/16
21-11/16
21-11/16
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
14

16

7-1/2

1/4

16-3/4

---

5/8-11

5000
FRAME
D E 2F H O P U V AA AB BA
5007S
5007L
12-1/2
12-1/2
10
10
22
22
15/16
15/16
26-27/32
26-27/32
30
30
2-1/2
3-7/8
6-1/2
11-1/8
4-NPT
4-NPT
26-7/8
26-7/8
8-1/2
8-1/2
5009S
5009L
12-1/2
12-1/2
10
10
28
28
15/16
15/16
26-27/32
26-27/32
30
30
2-1/2
3-7/8
6-1/2
11-1/8
4-NPT
4-NPT
26-7/8
26-7/8
8-1/2
8-1/2
5011S
5011L
12-1/2
12-1/2
10
10
36
36
15/16
15/16
26-27/32
26-27/32
30
30
2-1/2
3-7/8
6-1/2
11-1/8
4-NPT
4-NPT
26-7/8
26-7/8
8-1/2
8-1/2
NEMA C-FACE BA DIMENSIONS
143-5TC 2-3/4
182-4TC 3-1/2
213-5TC 4-1/4
254-6TC 4-3/4
FRAME NEMA FRAMES PRIOR TO 1953
D E F N U V BA
66 4-1/8 2-15/16 2-1/2 2-1/4 3/4 2-1/4 3-1/8
203 5 4 2-3/4 2-7/16 3/4 2 3-1/8
204 3-1/4
224 5-1/2 4-1/2 3-3/8 3-1/4 1 3 3-1/2
225 3-3/4
254 6-1/4 5 4-1/8 3-7/16 1-1/8 3-3/8 4-1/4
284 7 5-1/2 4-3/4 4-1/4 1-1/4 3-3/4 4-3/4
324 8 6-1/4 5-1/4 5-3/8 1-5/8 4-7/8 5-1/4
326 6
364 9 7 5-5/8 5-5/8 1-78/8 5-3/8 5-7/8
365 6-1/8
404 10 8 6-1/8 6-3/8 2-1/8 6-1/8 6-5/8
405 6-7/8
444 11 9 7-1/4 7-1/8 2-3/8 6-7/8 7-1/2
445 8-1/4
504 12-1/2 10 8 8-5/8 2-7/8 8-3/8 8-1/2
505 9

National Electrical Manufacturers Association (NEMA) is a trade association in the US who sets up technical standards. NEMA standardized on electric motor sizes based upon each specific horsepower, speed, and enclosure type to allow for easier replacement interchange between manufacturers. These size assignments are referred to as "Frame".

In the tables above, you will see the 3 different times that these standardized Frame sizes were revised to take advantage of motor technology and materials improvements which basically allowed for a reduction in physical sizes of the motors for the same horsepower, speed, and enclosure.

Keep in mind, that when replacing an older "U Frame" (1952 standard) or "Pre-U Frame" (Original standard) with the current "T Frame" size standard (1964 standard), we can provide you with Transition Bases which will place the smaller current frames into the same basic mounting position as the older frames. These Transition Bases are relatively inexpensive. However you will often have to replace your coupling or pulley bushing to account for the different shaft size.

Also be aware that these NEMA standards do NOT determine the overall total size of the motor which could be longer or wider. See our tech article "Size Matters" to understand this common headache.

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