which is the actual load, and from which
| actual load | 41,403 | |
| apparent load = | —————— = | ———— = 51,754 |
| power factor | .8 |
The current therefore at 440 volts is
| apparent load | 51,754 | |
| ——————— = | ————— = | 117.6 amperes |
| volts | 440 |
EXAMPLE.—A 50 horse power single phase 440 volt motor, having a full load efficiency of .92 and power factor of .8, is to be operated at a distance of 1,000 feet from the alternator. The wires are to be spaced 6 inches apart and the frequency is 60, and % loss 5. Determine: A, electrical horse power; B, watts; C, apparent load; D, current; E, size of wires; F, drop; G, voltage at the alternator.
A. Electrical horse power
| brake horse power | 50 | |
| E. H. P. = | ————————— × | —— = 54.3 |
| efficiency | .92 |
or,
54.3 × 746 = 40,508 watts
| 0000 | 2 No. 0 | 4 No. 3 | 8 No. 6 | 16 No. 9 | 32 No. 12 | 64 No. 15 |
| 000 | 2 " 1 | 4 " 4 | 8 " 7 | 16 " 10 | 32 " 13 | 64 " 16 |
| 00 | 2 " 2 | 4 " 5 | 8 " 8 | 16 " 11 | 32 " 14 | 64 " 17 |
| 0 | 2 " 3 | 4 " 6 | 8 " 9 | 16 " 12 | 32 " 15 | 64 " 18 |
| 1 | 2 " 4 | 4 " 7 | 8 " 10 | 16 " 13 | 32 " 16 | 64 " 19 |
| 2 | 2 " 5 | 4 " 8 | 8 " 11 | 16 " 14 | 32 " 17 | 64 " 20 |
| 3 | 2 " 6 | 4 " 9 | 8 " 12 | 16 " 15 | 32 " 18 | 64 " 21 |
| 4 | 2 " 7 | 4 " 10 | 8 " 13 | 16 " 16 | 32 " 19 | 64 " 22 |
| 5 | 2 " 8 | 4 " 11 | 8 " 14 | 16 " 17 | 32 " 20 | 64 " 23 |
| 6 | 2 " 9 | 4 " 12 | 8 " 15 | 16 " 18 | 32 " 21 | 64 " 24 |
| 7 | 2 " 10 | 4 " 13 | 8 " 16 | 16 " 19 | 32 " 22 | 64 " 25 |
| 8 | 2 " 11 | 4 " 14 | 8 " 17 | 16 " 20 | 32 " 23 | 64 " 26 |
| 9 | 2 " 12 | 4 " 15 | 8 " 18 | 16 " 21 | 32 " 24 | 64 " 27 |
| 10 | 2 " 13 | 4 " 16 | 8 " 19 | 16 " 22 | 32 " 25 | 64 " 28 |
| 11 | 2 " 14 | 4 " 17 | 8 " 20 | 16 " 23 | 32 " 26 | 64 " 29 |
| 12 | 2 " 15 | 4 " 18 | 8 " 21 | 16 " 24 | 32 " 27 | 64 " 30 |
| 13 | 2 " 16 | 4 " 19 | 8 " 22 | 16 " 25 | 32 " 28 | — |
| 14 | 2 " 17 | 4 " 20 | 8 " 23 | 16 " 26 | 32 " 29 | — |
| 15 | 2 " 18 | 4 " 21 | 8 " 24 | 16 " 27 | 32 " 30 | — |
| 16 | 2 " 19 | 4 " 22 | 8 " 25 | 16 " 28 | — | — |
| 17 | 2 " 20 | 4 " 23 | 8 " 26 | 16 " 29 | — | — |
| 18 | 2 " 21 | 4 " 24 | 8 " 27 | 16 " 30 | — | — |
| 19 | 2 " 22 | 4 " 25 | 8 " 28 | — | — | — |
| 20 | 2 " 23 | 4 " 26 | 8 " 29 | — | — | — |
| 21 | 2 " 24 | 4 " 27 | 8 " 30 | — | — | — |