: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

:catat: Answer:

V = 220 Volt

f = 50 Hz

I = 1.24 A

P = 200 W

Cos phi = ...?

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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)
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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 * 10

^{3} 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.