How to Calculate Capacitor Rating for a Motor

Data and Graphs

Need to know what size capacitor is required for your motor?

This table will guide you to find the correct size capacitor.

Recommended capacitor rating for direct connection induction motors to improve power factors to
0.95 or better at all loads. This table will help you calculate the required capacitor size relative to motor size.

Example: For a 10ph motor, with a motor speed of 750 RPM, the rated capacitor required will be 4mF.

Capacitor rating in kVAr when motor speed is:

Motor Power		Motor Speed (RPM)
kW	hp	3000	1500	1000	750	600	500
1.50	2	0.5	1	1	1.5	1.5	1.5
2.20	3	0.75	1	1	1.5	2	2
3.70	5	1	1.5	1.5	2.5	3	3
5.50	7.5	1.5	2	2.5	3	4	4
7.50	10	2.5	3	3	4	5	5
9	12	3	3	4	5	6	6
11	15	3	4	4	6	6	6
15	20	5	5	6	6	8	10
18.50	25	6	6	6	8	10	12
22.50	30	6	8	8	10	12	14
25	35	8	8	10	12	14	14
30	40	8	10	10	14	14	16
33	45	8	10	12	14	16	18
37	50	10	12	14	16	18	18
40	54	10	12	14	16	18	20
45	60	12	12	14	18	20	22
51	70	12	14	18	18	22	24
55	75	14	16	18	20	22	26
59	80	14	16	20	20	24	28
63	85	14	18	20	22	24	28
68	90	16	20	22	24	26	30
72	95	16	20	24	24	28	30
75	100	18	22	24	26	28	32
79	105	18	22	24	26	30	32
80	110	18	24	26	28	30	34
90	125	22	26	28	30	34	36
100	136	24	28	28	30	34	38
105	140	24	28	30	32	36	40
110	150	26	28	30	32	36	42
120	160	28	30	32	34	38	46
123	165	28	30	32	36	40	48
126	170	30	32	32	36	40	48
129	175	30	32	34	38	42	50
135	180	30	34	34	38	44	50
140	190	32	34	36	40	46	52
150	200	32	36	36	44	46	54

Download PDF - How to Calculate Capacitor Rating for a Motor