ABSTRACT

Cable size 50 × 37.5 75 × 50 75 × 75 16 mm2 20 40 60 25 mm2 13 27 40 50 mm2 8 15 22

16. 75 mm × 50 mm or 100 mm × 37.5 mm 17. 8036 mm2 (about 90 mm × 90 mm) use 100 mm × 100 mm 18. (c) 19. (b) 20. 75 mm × 75 mm trunking

22. 25 mm conduit, draw in box after second bend 23. (a) 32 mm conduit, (b) adequate room exists but

re-calculation of new and existing cable ratings will be necessary

24. (a) 50 mm × 50 mm or 75 mm × 38 mm trunking, (b) 32 mm conduit, (c) difficulty may result when extending from stop-end of 75 mm × 38 mm trunking

1. 3.21 sec 2. 20 sec (2 min) 3. 3,870 C

1. (a) 106, (b) 12.5, (c) 24, (d) 1.965, (e) 154.94, (f) 346.2, (g) 59.3 k, (h) 2 290 000, (i) 0.0997, (j) 57 425m

2. (a) 22, (b) 2.35, (c) 1.75, (d) 2.71, (e) 1.66, (f) 13.42, (g) 6.53, (h) 1805, (i) 499 635m, (j) 0.061M

3. 3.36 4. 21.1 5. 9 6. 533, 19 7. 133.6, 30.4 8. 2.76 9. (c) 10. (d)

11. (b) 12. (b)

1. (a) 1, (b) 1.58, (c) 3.94, (d) 1.89, (e) 2.26, (f) 11.7, (g) 6, (h) 5, (i) 10

2. (a) 16, (b) 6.67, (c) 7.2, (d) 6, (e) 42, (f) 2000, (g) 300, (h) 37.5, (i) 38, (j) 17.3

3. (a) 2.13A, (b) 8.52A 4. (a) 4.2V, (b) 3.53A, 26.4A 5. 0.125 6. 25A, 24.4A, 21.6A 7. 10.9 8. 40A, 30A 9. 20A 10. 0.1

11. (a) 0.009 23, (b) 1.2V, (c) 66.7A, 50A, 13.3A 12. (a) IA = IB = ID − 2.5A, IC = 6.67A, (b) 9.17A,

(c) UA = 10 V, UB = 12.5V, UC = 40V, UD = 17.5V, (d) 9.4A

13. (d) 14. (a) 15. 0.365 16. 24V, 12.4V 17. (a) 0.0145, 18. 141A, 109A 19. 0.137

20. 971 21. (a) 152A, 121A, 227A, (b) 1.82V, (c) 1.82V 22. (b) 23. (b)

1. (a) 3.6, (b) 5, (c) 4A in 9 resistance, 6A in 6 resistance, 10A in 1.4 resistance

2. (a) 2 , (b) 12V 3. 2.25 4. 2.86 5. (a) 5.43, (b) 3.68A 6. 26.2V 7. 0.703A in 7 resistance, 0.547A in 9 resistance 8. 11.7 9. 0.174A, 0.145A, 50.6W 10. 37.73

11. 25 .4 12. (a) 20.31A, (b) 0.23, (c) 2.64kW 13. 216.3V, 213.37V 14. (a) 5, (b) IA = 3 A, IB = 12A, IC = 15A 15. 6 16. (a) 20A, (b) 2, (c) 56A 17. 2.96 V 18. 4.25 V 19. 6.96V 20. 0.0306 21. (a) 1.09A, 0.78A, (b) 5.44V, (c) 1.05W 22. (a) 4.37V, (b) 0.955W, 0.637W 23. 88.7V 24. 107V 25. 117V, 136W, 272W 26. 2.59 27. (a) 4.4, (b) 15.9V, (c) 1.72 28. (b) 29. (d) 30. (a)

1. 1.2 2. 0.222 3. 6mm2 4. 10mm2

5. 43.2m 6. 4.17V, 6.66V 7. 0.001 48 8. 6mm 9. 0.623 10. 1.71V 11. 48m 12. 0.071

13. 47.4m 14. 0.006 15. 25mm 16. 2.5mm2

17. (a) 1.187, (b) 0.297, (c) 0.178, (d) 0.051, (e) 0.0356

18. (a) 0.155, (b) 0.111, (c) 0.34 19. (a) 1.32, (b) 0.528, (c) 8.8 20. 0.15 21. 2.63 22. (a) 23. (c) 24. (a)

1. P (watts) 1440 3000 1600 1000 20 1000 2350 1080 I (amperes) 6 12 6.67 150 0.2 5.45 5.1 4.5 6.67 100 220 460 240

2. 30W 3. 4370W 4. (a) 13.04A, (b) 6.53A, (c) 1.96A, (d) 15.22A, (e) 30.44A,

(f) 0.26A, (g) 0.43A, (h) 8.7A, (i) 3.26A, (j) 0.065A 5. 108V 6. 203W 7. (a) 18.75A, (b) 20.45A 8. 748W 9. 6A 10. 13.04A 11. 633W

12. 0.2A, 23W 13. 17.4A 14. (a) 6.413kW, (b) 83.7W, (c) 222V 15. 29.2 16. (a) 460V, (b) 7.05kW, (c) 76.9W 17. (a) 62.1W, 70.9W, (b) 286W, 250W 18. 453W, 315W 19. 40.5V, 0.78, 750W 20. (a) 434V, (b) 15.6kW, (c) 216W, (d) 433V 21. (c) 22. (b) 23. (c) 24. (a)

1. Power (W) 1500 200 1800 1440 1000 2640 100 42.25 Current (A) 10 5 15 12 4.2 11.49 0.42 1.3 Resistance () 15 8 8 10 56.7 20 567 25

2. 130W 3. 29.4W 4. 5A 5. 1.73kW 6. 576 7. (a) 6.21V, (b) 71.4W 8. 530W 9. 20A 10. 59.4W 11. 125 12. 63.4W

13. 419W 14. 0.248W 15. 0.8A

1. 72W 2. 130 3. 4 4. 120V 5. Power (W) 128 100 60 125 768 1800 42.24 36

Voltage (V) 80 240 250 50 240 220 3.5 12 Resistance () 50 576 1042 20 75 26.9 0.29 4

6. 15V 7. 557W 8. 52.9 9. 170W 10. 161 11. (a) 28.8, (b) 19.2, (c) 16.5, (d) 128, (e) 960,

(f) 8.23, (g) 576, (h) 38.4,(i) 76.8, (j) 14.4, 12. 79.1V 13. 4.19A 14. (a) 0.149A, (b) 29.8W 15. 115, 28.8, 500W, 2000W 16. 19A, 126W, 81A, 538W 17. 750W, 3000W 18. Power (W) 25.6 250 360 400 600 960

Current (A) 0.8 2.5 3 3.15 3.87 4.9 Resistance () 40 40 40 40.3 40 40 approx.