Electrical Power Systems Technology

Electrical Power Conversion Systems 305

power factor, and transpose. Thus, we have IP = PP/VP × pf. Substitution

of the values for each leg of the system gives us:

1. PP–A
   *IP–A = ————
   VP × pf

2000 watts

= ————————

120 volts × 0.75

= 22.22 amperes

*This notation means phase current (IP) of “A” power line.

2. PP–B
   *IP–B = ————
   VP × pf

1000 watts

= ————————

120 volts × 0.85

= 9.8 amperes

3. PP–C
   *IP–C = ————
   VP × pf

3000 watts

= ————————

120 volts × 1.0

= 25.0 amperes

To determine the total power, use the total power formula for a three-

phase unbalanced system, which was just given:

PT = PP–A + PP–B + PP–C

= 2000 + 1000 + 3000

= 6000 watts (6 kW)