Electrical Power worksheet

1. Current: 15.38 A

1. Turn P = V × I × PF around to get the current: divide the watts by V × PF

   $I$$=\frac{\mathrm{2,000}}{130\times 1}$$=15.3846153846\text{\hspace{0.17em}A}$

2. Apparent power, the total load the supply carries: multiply volts × amps, then divide by 1000 for kVA

   $S$$=\frac{130\times 15.3846153846}{\mathrm{1,000}}$$=2\text{\hspace{0.17em}kVA}$

2. Current: 15 A

1. Turn P = V × I around to get the current: divide the watts by V

   $I$$=\frac{\mathrm{1,200}}{80}$$=15\text{\hspace{0.17em}A}$

2. For DC, volt-amps equal watts. Divide by 1000 to get kVA

   $S$$=\frac{80\times 15}{\mathrm{1,000}}$$=1.2\text{\hspace{0.17em}kVA}$

3. Voltage: 103.85 V

1. Turn P = V × I × PF around to get the voltage

   $V$$=\frac{\mathrm{1,350}}{13\times 1}$$=103.8461538462\text{\hspace{0.17em}V}$

2. Apparent power, the total load the supply carries: multiply volts × amps, then divide by 1000 for kVA

   $S$$=\frac{103.8461538462\times 13}{\mathrm{1,000}}$$=1.35\text{\hspace{0.17em}kVA}$

4. Current: 92.31 A

1. Convert kVA to volt-amperes (1 kVA = 1000 VA)

   $12\text{\hspace{0.17em}kVA}\times \mathrm{1,000}$$=\mathrm{12,000}\text{\hspace{0.17em}VA}$

2. Divide the volt-amps by the voltage to get the current. kVA already includes the power factor, so no extra factor is needed

   $I$$=\frac{\mathrm{12,000}}{130}$$=92.3076923077\text{\hspace{0.17em}A}$

5. Real power: 4,364.77 W

1. Real power for three-phase AC: P = √3 × V × I × PF

   $P$$=\sqrt{3}\times 140\times 18\times 1$$=\mathrm{4,364.7680350736}\text{\hspace{0.17em}W}$

2. Apparent power, the total load the supply carries: multiply √3 × volts × amps, then divide by 1000 for kVA

   $S$$=\frac{\sqrt{3}\times 140\times 18}{\mathrm{1,000}}$$=4.3647680351\text{\hspace{0.17em}kVA}$

6. Current per line: 63.71 A

1. Convert kVA to volt-amperes (1 kVA = 1000 VA)

   $16\text{\hspace{0.17em}kVA}\times \mathrm{1,000}$$=\mathrm{16,000}\text{\hspace{0.17em}VA}$

2. Divide the volt-amps by √3 × the voltage to get the current. kVA already includes the power factor, so no extra factor is needed

   $I$$=\frac{\mathrm{16,000}}{\sqrt{3}\times 145}$$=63.7076159106\text{\hspace{0.17em}A}$

3. Real power: multiply the volt-amps by the power factor, the share that does useful work

   $P$$=\mathrm{16,000}\times 1$$=\mathrm{16,000}\text{\hspace{0.17em}W}$

7. Current: 166.67 A

1. Convert kVA to volt-amperes (1 kVA = 1000 VA)

   $15\text{\hspace{0.17em}kVA}\times \mathrm{1,000}$$=\mathrm{15,000}\text{\hspace{0.17em}VA}$

2. Divide the volt-amps by the voltage to get the current. kVA already includes the power factor, so no extra factor is needed

   $I$$=\frac{\mathrm{15,000}}{90}$$=166.6666666667\text{\hspace{0.17em}A}$

3. Real power: multiply the volt-amps by the power factor, the share that does useful work

   $P$$=\mathrm{15,000}\times 1$$=\mathrm{15,000}\text{\hspace{0.17em}W}$

8. Current: 9.09 A

1. Turn P = V × I around to get the current: divide the watts by V

   $I$$=\frac{\mathrm{1,000}}{110}$$=9.0909090909\text{\hspace{0.17em}A}$

2. For DC, volt-amps equal watts. Divide by 1000 to get kVA

   $S$$=\frac{110\times 9.0909090909}{\mathrm{1,000}}$$=1\text{\hspace{0.17em}kVA}$

9. Voltage: 285.71 V

1. Turn P = V × I around to get the voltage

   $V$$=\frac{\mathrm{2,000}}{7}$$=285.7142857143\text{\hspace{0.17em}V}$

2. For DC, volt-amps equal watts. Divide by 1000 to get kVA

   $S$$=\frac{285.7142857143\times 7}{\mathrm{1,000}}$$=2\text{\hspace{0.17em}kVA}$

10. Current: 104.48 A

1. Convert kVA to volt-amperes (1 kVA = 1000 VA)

   $14\text{\hspace{0.17em}kVA}\times \mathrm{1,000}$$=\mathrm{14,000}\text{\hspace{0.17em}VA}$

2. Divide the volt-amps by the voltage to get the current. kVA already includes the power factor, so no extra factor is needed

   $I$$=\frac{\mathrm{14,000}}{134}$$=104.4776119403\text{\hspace{0.17em}A}$