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:1: We have an electric motor that used to drive washing machine. The electric motor has specifications: voltage is 220 Volt single phase, frequency is 50 Hz, current of electricity is 1.24 Ampere and real power on the name plate is 200 Watt. How many cos phi of electricity of the motor?

:catat: Answer:
V = 220 Volt
f = 50 Hz
I = 1.24 A
P = 200 W
Cos phi = ...?

===================================
The formula of real power electricity in single phase motor
P = V I Cos phi . . . . . (Watt)

then

The formula of cos phi in single phase motor
Cos phi = P / (V I)
or
Cos φ = P / (V I)

====================================

Cos phi = 200 / (220 * 1.24)
Cos phi = 0.733.

:2: In the paper bag factory has an electric motor that has specifications: voltage is 200 Volt single phase, frequency is 60 Hz, current of electricity is 9.5 Ampere and real power on the name plate is 1.5 kW. How many cos φ of electricity of the motor?

:catat: Answer:
V = 200 Volt
f = 60 Hz
I = 9.5 A
P = 1.5 kW → convert kW into W → 1.5 * 103 W = 1500 W
Cos φ = ...?

Cos φ = P / (V I)
Cos φ = 1500 / (200 * 9.5)
Cos φ = 0.79.

:3: The electric motor has specifications: voltage is 400 Volt single phase, frequency is 70 Hz, current of electricity is 10.97 Ampere and real power on the name plate is 4 HP. How many cos φ of electricity of the motor?

:catat: Answer:
V = 400 Volt
f = 70 Hz
I = 10.97 A
P = 4 HP → convert HP into W → 4 * 746 W = 2984 W
Cos φ = ...?

Cos φ = P / (V I)
Cos φ = 2984 / (400 * 10.97)
Cos φ = 0.68.

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