Full-Load Currents

Direct - Current Motors
(Running at Base Speed)

*For conductor sizing only

HP Armature Voltage Rating*
90V 120V 180V 240V 500V 550V
1/4
1/3
1/2
3/4		 4.0
5.2
6.8
9.6		 3.1
4.1
5.4
7.6		 2.0
2.6
3.4
4.8		 1.6
2.0
2.7
3.8		 --
--
--
--		 --
--
--
--
1
1 1/2
2		 12.2
--
--		 9.5
13.2
17		 6.1
8.3
10.8		 4.7
6.6
8.5		 --
--
--		 --
--
--
3
5
7 1/2		 --
--
--		 25
40
58		 16
27
39		 12.2
20
29		 --
--
13.6		 --
--
12.2
10
15
20
25		 --
--
--
--		 76
--
--
--		 51
--
--
--		 38
55
72
89		 18
27
34
43		 16
24
31
38
30
40
50
60
75		 --
--
--
--
--		 --
--
--
--
--		 --
--
--
--
--		 106
140
173
206
255		 51
67
83
99
123		 46
61
75
90
111
100
125
150
200		 --
--
--
--		 --
--
--
--		 --
--
--
--		 341
425
506
675		 164
205
246
330		 148
185
222
294
>200 HP
Approx.
Amps/HP		 -- -- -- 3.4 1.7 1.5

*These are average direct-current quantities. Branch-circuit conductors supplying a single motor shall have an ampacity not less than 125 percent of the motor full-load curent rating.

Armature Current Varies Inversely as Applied Voltage.

Example: 40 HP Motor, 300 Volt Armature

ARMATURE CURRENT = 140 x 240/300 = 112 AMPS

Based on Table 430-147 of the National Electrical Code,® 1993.

Three-Phase Synchronous Motors Unity Power Factor*

*For conduit sizing only.

HP 460V 575V 2300V 4000V
100
125
150		 100
125
150		 80
100
120		 20
25
30		 11.5
14.4
17.2
200
250
300		 200
250
300		 160
200
240		 40
50
60		 23
28.7
34.5
350
400
500		 353
403
500		 282
322
400		 70.5
80.5
100		 40.5
46.3
57.5
600
700
800		 600
705
805		 480
564
644		 120
141
161		 69
81
92.6
900
1000		 905
960		 724
768		 181
192		 104
110

 

Single-Phase Motors

HP 115V 200V 230V
1/6
1/4
1/3
1/2
3/4		 4.4
5.8
7.2
9.8
13.8		 2.5
3.3
4.1
5.6
7.9		 2.2
2.9
3.6
4.9
6.9
1
1 1/2
2
3		 16
20
24
34		 9.2
11.5
13.8
19.6		 8
10
12
17
5
7 1/2
10		 56
80
100		 32.2
46
57.5		 28
40
50

Branch-circuit conductors supplying a single motor shall have an ampacity not less than 125 percent of the motor full-load current rating.

Based on Table 430-148 of the National Electrical Code,® 1993.

The information presented within this section has been carefully prepared and is believed to be accurate. Alan Wire Company makes no warranties, expressed or implied, and disclaim any responsibility or liability for loss or damage as a result of use of this information.