Mechanical energy is supplied to DC generator at ___

Electrical Engineering MCQ Electrical Machines MCQ
1

Mechanical energy is supplied to DC generator at the rate of 4200 J / s.

The generator delivers 32.2 Amp at 120 V.

What is the percentage efficiency of the generator?

A. 201.02 V.
B. 205 V.
C. 210 V.
D. 212 V.

Show Answer

Answer: A

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2

To calculate the efficiency of the generator, we need to determine the electrical power output and the mechanical power input.

Given:
Mechanical power input = 4200 J/s
Current (I) = 32.2 A
Voltage (V) = 120 V

The electrical power output can be calculated using the formula:
Electrical power output = Voltage * Current

Electrical power output = 120 V * 32.2 A
Electrical power output = 3864 W

Now, we can calculate the efficiency using the formula:
Efficiency = (Electrical power output / Mechanical power input) * 100

Efficiency = (3864 W / 4200 J/s) * 100
Efficiency = (0.92) * 100
Efficiency = 92%

Therefore, the percentage efficiency of the generator is 92%.