Suggested Capacitor Ratings for T-Frame NEMA Class B Motors
TABLE 1A
| Nominal Motor Speed | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 3600 RPM | 1800 RPM | 1200 RPM | ||||||||||
| Induction Motor Rating (HP) |
Capacitor Rating (KVAR) | Line Current Reduced (%) |
Capacitor Rating (KVAR) | Line Current Reduced (%) |
Capacitor Rating (KVAR) | Line Current Reduced (%) |
||||||
| 3 | 1.5 | 14 | 1.5 | 23 | 2.5 | 28 | ||||||
| 5 | 2 | 14 | 2.5 | 22 | 3 | 26 | ||||||
| 7.5 | 2.5 | 14 | 3 | 20 | 4 | 21 | ||||||
| 10 | 4 | 14 | 4 | 18 | 5 | 21 | ||||||
| 15 | 5 | 12 | 5 | 18 | 6 | 20 | ||||||
| 20 | 6 | 12 | 6 | 17 | 7.5 | 19 | ||||||
| 25 | 7.5 | 12 | 7.5 | 17 | 8 | 19 | ||||||
| 30 | 8 | 11 | 8 | 16 | 10 | 19 | ||||||
| 40 | 12 | 12 | 13 | 15 | 16 | 19 | ||||||
| 50 | 15 | 12 | 18 | 15 | 20 | 19 | ||||||
| 60 | 18 | 12 | 21 | 14 | 22.5 | 17 | ||||||
| 75 | 20 | 12 | 23 | 14 | 25 | 15 | ||||||
| 100 | 22.5 | 11 | 30 | 14 | 30 | 12 | ||||||
| 125 | 25 | 10 | 36 | 12 | 35 | 12 | ||||||
| 150 | 30 | 10 | 42 | 12 | 40 | 12 | ||||||
| 200 | 35 | 10 | 50 | 11 | 50 | 10 | ||||||
| 250 | 40 | 11 | 60 | 10 | 62.5 | 10 | ||||||
| 300 | 45 | 11 | 68 | 10 | 75 | 12 | ||||||
| 350 | 50 | 12 | 75 | 8 | 90 | 12 | ||||||
| 400 | 75 | 10 | 80 | 8 | 100 | 12 | ||||||
| 450 | 80 | 8 | 90 | 8 | 120 | 10 | ||||||
| 500 | 100 | 8 | 120 | 9 | 150 | 12 | ||||||
Suggested Capacitor Ratings for T-Frame NEMA Class B Motors
TABLE 1B
| Nominal Motor Speed | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 900 RPM | 720 RPM | 600 RPM | ||||||||||
| Induction Motor Rating (HP) |
Capacitor Rating (KVAR) | Line Current Reduced (%) |
Capacitor Rating (KVAR) | Line Current Reduced (%) |
Capacitor Rating (KVAR) | Line Current Reduced (%) |
||||||
| 3 | 3 | 38 | 3 | 40 | 4 | 40 | ||||||
| 5 | 4 | 31 | 4 | 40 | 5 | 40 | ||||||
| 7.5 | 5 | 28 | 5 | 38 | 6 | 45 | ||||||
| 10 | 6 | 27 | 7.5 | 36 | 8 | 38 | ||||||
| 15 | 7.5 | 24 | 8 | 32 | 10 | 34 | ||||||
| 20 | 9 | 23 | 10 | 29 | 12 | 30 | ||||||
| 25 | 10 | 23 | 12 | 25 | 18 | 30 | ||||||
| 30 | 14 | 22 | 15 | 24 | 22.5 | 30 | ||||||
| 40 | 18 | 21 | 22.5 | 24 | 25 | 30 | ||||||
| 50 | 22.5 | 21 | 24 | 24 | 30 | 30 | ||||||
| 60 | 26 | 20 | 30 | 22 | 35 | 28 | ||||||
| 75 | 28 | 17 | 33 | 14 | 40 | 19 | ||||||
| 100 | 35 | 16 | 40 | 15 | 45 | 17 | ||||||
| 125 | 42 | 14 | 45 | 15 | 50 | 17 | ||||||
| 150 | 52.5 | 14 | 52.5 | 14 | 60 | 17 | ||||||
| 200 | 65 | 13 | 68 | 13 | 90 | 17 | ||||||
| 250 | 82 | 13 | 87.5 | 13 | 100 | 17 | ||||||
| 300 | 100 | 14 | 100 | 13 | 120 | 17 | ||||||
| 350 | 120 | 13 | 120 | 13 | 135 | 15 | ||||||
| 400 | 130 | 13 | 140 | 13 | 150 | 15 | ||||||
| 450 | 140 | 12 | 160 | 14 | 160 | 15 | ||||||
| 500 | 160 | 12 | 180 | 13 | 180 | 15 | ||||||
Suggested Capacitor Ratings for Non T-Frame NEMA Class B Open Squirrel-Cage Motors
TABLE 2A
| Nominal Motor Speed | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 3600 RPM | 1800 RPM | 1200 RPM | ||||||||||
| Induction Motor Rating (HP) |
Capacitor Rating (KVAR) | Line Current Reduced (%) |
Capacitor Rating (KVAR) | Line Current Reduced (%) |
Capacitor Rating (KVAR) | Line Current Reduced (%) |
||||||
| 3 | 1.5 | 14 | 1.5 | 15 | 1.5 | 20 | ||||||
| 5 | 2 | 12 | 2 | 13 | 2 | 17 | ||||||
| 7.5 | 2.5 | 11 | 2.5 | 12 | 3 | 15 | ||||||
| 10 | 3 | 10 | 3 | 11 | 3.5 | 14 | ||||||
| 15 | 4 | 9 | 4 | 10 | 5 | 13 | ||||||
| 20 | 5 | 9 | 5 | 10 | 6.5 | 12 | ||||||
| 25 | 6 | 9 | 6 | 10 | 7.5 | 11 | ||||||
| 30 | 7 | 8 | 7 | 9 | 9 | 11 | ||||||
| 40 | 9 | 8 | 9 | 9 | 11 | 10 | ||||||
| 50 | 12 | 8 | 11 | 9 | 13 | 10 | ||||||
| 60 | 14 | 8 | 14 | 8 | 15 | 10 | ||||||
| 75 | 17 | 8 | 16 | 8 | 18 | 10 | ||||||
| 100 | 22 | 8 | 21 | 8 | 25 | 9 | ||||||
| 125 | 27 | 8 | 26 | 8 | 30 | 9 | ||||||
| 150 | 32.5 | 8 | 30 | 8 | 35 | 9 | ||||||
| 200 | 40 | 8 | 37.5 | 8 | 42.5 | 9 | ||||||
| 250 | 50 | 8 | 45 | 7 | 52.5 | 8 | ||||||
| 300 | 57.5 | 8 | 52.5 | 7 | 60 | 8 | ||||||
| 350 | 65 | 8 | 60 | 7 | 67.5 | 8 | ||||||
| 400 | 70 | 8 | 65 | 6 | 75 | 8 | ||||||
| 450 | 75 | 8 | 67.5 | 6 | 80 | 8 | ||||||
| 500 | 77.5 | 8 | 72.5 | 6 | 82.5 | 8 | ||||||
Suggested Capacitor Ratings for Non T-Frame NEMA Class B Open Squirrel-Cage Motors
TABLE 2B
| Nominal Motor Speed | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 900 RPM | 720 RPM | 600 RPM | ||||||||||
| Induction Motor Rating (HP) |
Capacitor Rating (KVAR) | Line Current Reduced (%) |
Capacitor Rating (KVAR) | Line Current Reduced (%) |
Capacitor Rating (KVAR) | Line Current Reduced (%) |
||||||
| 3 | 2 | 27 | 2.5 | 35 | 3.5 | 41 | ||||||
| 5 | 3 | 25 | 4 | 32 | 4.5 | 37 | ||||||
| 7.5 | 4 | 22 | 5.5 | 30 | 6 | 34 | ||||||
| 10 | 5 | 21 | 6.5 | 27 | 7.5 | 31 | ||||||
| 15 | 6.5 | 18 | 8 | 23 | 9.5 | 27 | ||||||
| 20 | 7.5 | 16 | 9 | 21 | 12 | 25 | ||||||
| 25 | 9 | 15 | 11 | 20 | 14 | 23 | ||||||
| 30 | 10 | 14 | 12 | 18 | 16 | 22 | ||||||
| 40 | 12 | 13 | 15 | 16 | 20 | 20 | ||||||
| 50 | 15 | 12 | 19 | 15 | 24 | 19 | ||||||
| 60 | 18 | 11 | 22 | 15 | 27 | 19 | ||||||
| 75 | 21 | 10 | 26 | 14 | 32.5 | 18 | ||||||
| 100 | 27 | 10 | 32.5 | 13 | 40 | 17 | ||||||
| 125 | 32.5 | 10 | 40 | 13 | 47.5 | 16 | ||||||
| 150 | 37.5 | 10 | 47.5 | 12 | 52.5 | 15 | ||||||
| 200 | 47.5 | 10 | 60 | 12 | 65 | 14 | ||||||
| 250 | 57.5 | 9 | 70 | 11 | 77.5 | 13 | ||||||
| 300 | 65 | 9 | 80 | 11 | 87.5 | 12 | ||||||
| 350 | 75 | 9 | 87.5 | 10 | 95 | 11 | ||||||
| 400 | 85 | 9 | 95 | 10 | 105 | 11 | ||||||
| 450 | 92.5 | 9 | 100 | 9 | 110 | 11 | ||||||
| 500 | 97.5 | 9 | 107.5 | 9 | 115 | 10 | ||||||
Tables 1 & 2 apply to three phase, 60 Hz motors when switched with capacitors as a single unit.
© IEEE Std 141-1986
