Tables > Motors > General > Various data, A.C.
Data on Three-phase Alternating Current Motors

Motor Horsepower Motor Ampere Size Breaker Size Starter Heater Ampere Size Wire Size Conduit
1/2230V
460
2.2
1.1
15
15
00
00
2.530
1.265
12
12
3/4"
3/4
3/4230
460
3.2
1.6
15
15
00
00
3.680
1.840
12
12
3/4
3/4
1230
460
4.2
2.1
15
15
00
00
4.830
2.415
12
12
3/4
3/4
1 1/2230
460
6.0
3.0
15
15
00
00
6.900
3.450
12
12
3/4
3/4
2230
460
6.8
3.4
15
15
0
00
7.820
3.910
12
12
3/4
3/4
3230
460
9.6
4.8
20
15
0
0
11.040
5.520
12
12
3/4
3/4
5230
460
15.2
7.6
30
15
1
0
17.840
8.740
12
12
3/4
3/4
7 1/2230
460
22
11
45
20
1
1
25.300
12.650
10
12
3/4
3/4
10230
460
28
14
60
30
2
1
32.200
16.100
10
12
3/4
3/4
15230
460
42
21
70
40
2
2
48.300
24.150
6
10
1
3/4
20230
460
54
27
100
50
3
2
62.100
31.050
6
10
1
3/4
25230
460
68
34
100
50
3
2
78.200
39.100
4
8
1 1/2
1
30230
460
80
40
125
70
3
3
92.000
46.000
3
8
1 1/2
1
40230
460
104
52
175
100
4
3
119.600
59.800
1
6
1 1/2
1
50230
460
130
65
200
150
4
3
149.500
74.750
00
4
2
1 1/2
60230
460
154
77
250
200
5
4
177.10
88.55
000
3
2
1 1/2
75230
460
192
96
300
200
5
4
220.80
110.40
250kcmil
2
2 1/2
1 1/2
100230
460
248
124
400
200
5
4
285.20
142.60
350kcmil
0
3
2
125230
460
312
156
500
250
6
5
358.80
179.40
600kcmil
000
3 1/2
2
150230
460
360
180
600
300
6
5
414.00
207.00
700kcmil
0000
4
2 1/2

*Overcurrent device may have to be increased due to starting current and load conditions. See NEC 430-52, Table 430-152. Wire size based on 75 degrees Celsius terminations and 75 degrees Celsius insulation.
**Overload heater must be based on motor nameplate & sized per NEC 430-32.
***Conduit size based on Rigid Metal Conduit with some spare capacity. For minimum size & other conduit types, see NEC Appendix C.
  1. Wire & conduit size will vary depending on type of insulation & termination listing.
  2. The preceding calculations apply to induction type, squirrel-cage, and wound-rotor motors only.
  3. The voltages listed are rated motor voltages; corresponding nominal system voltages are 220V to 240V, and 440V to 480V.
  4. Hertz: Preferred terminology for cycles per second.
  5. Form coil: Coil made with rectangular or square wire.
  6. Mush coil: Coil made with round wire.
  7. Slip: Percentage difference between synchronous and operating speeds.
  8. Synchronous speed: Maximum speed for A.C. motors or (Frequency * 120) / Poles.
  9. Full load speed: Speed at which rated horsepower is developed.
  10. Poles: Number of magnetic poles set up inside the motor by the placement and connection of the windings.
 
 
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