Electrical Motors - Full Load Amps

Full load amps for single and 3-phase 460 volts, 230 volts and 115 volts electric motors. Includes single-phase, three-phase, and DC motor specifications.

Full Load Amps Rules of Thumb

As a 'rules of thumb' amps horsepower rating can be estimated to:

115 volts motor - single-phase: 14 amps/hp
230 volts motor - single-phase: 7 amps/hp
230 volts motor - 3-phase: 2.5 amps/hp
460 volts motor - 3-phase: 1.25 amps/hp

Always check nameplate information before designing protective devices, wiring and switch gear.

Power (hp)	Power (kW)	115V	208V	230V
1/6	0.13	4.4	2.4	2.2
1/4	0.19	5.8	3.2	2.9
1/3	0.25	7.2	4.0	3.6
1/2	0.38	9.8	5.4	4.9
3/4	0.56	13.8	7.6	6.9
1	0.75	16	8.8	8
1 1/2	1.1	20	11	10
2	1.5	24	13.2	12
3	2.3	34	18.7	17
5	3.8	56	30.8	28

Power (hp)	Power (kW)	115V	230V	460V	575V
1/2	0.38	4	2	1	0.8
3/4	0.56	5.6	2.8	1.4	1.1
1	0.75	7.2	3.6	1.8	1.4
1 1/2	1.1	10.4	5.2	2.6	2.1
2	1.5	13.6	6.8	3.4	2.7
3	2.3	9.6	4.8	3.9
5	3.8	15.2	7.6	6.1
7 1/2	5.6	22	11	9
10	7.5	28	14	11
15	11	42	21	17
20	15	54	27	22
25	19	68	34	27
30	23	80	40	32
40	30	104	52	41
50	38	130	65	52
60	45	154	77	62
75	56	192	96	77
100	75	248	124	99

Power (hp)	Power (kW)	230V	440V
1/4	0.19	0.81	0.42
1/3	0.25	1.1	0.56
1/2	0.37	1.6	0.85
3/4	0.56	2.4	1.3
1	0.75	3.2	1.7
1 1/2	1.1	4.9	2.5
2	1.5	6.5	3.4
3	2.2	9.7	5.1
5	3.7	16	8.5
7 1/2	5.6	24	13
10	7.5	32	17
15	11	49	25
20	15	65	34
30	22	97	51
50	37	162	85
75	56	243	127
100	75	324	170

Important Notes

Motor Load Ranges:

Acceptable for short-period: 20 - 120%
Acceptable for operating: 50 - 100%
Optimum efficiency: 60 - 80%

Most electric motors are designed to run at 50% to 100% of rated load with maximum efficiency usually near 75% of rated load.

Unit Conversion:

1 hp = 745.7 W = 0.746 kW = 550 ft·lb/s = 2,545 Btu/h = 33,000 ft·lb/m = 1.0139 metric horsepower ≈ 1.0 kVA

For 115V DC motors: The amps is twice the amps for 230V