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How to Calculate Capacitor Rating for a Motor

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 10hp motor, with a motor speed of 750 RPM, the rated capacitor required will be 4 kVAr.  

Capacitor rating in kVAr when motor speed is:

Motor Power (3ph)                                          Motor Speed (RPM)

kWhp300015001000750600500

1.50

2

.5

1

1

1.5

1.5

1.5

2.20

3

.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

24

26

28

30

34

32

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