Question 208Electricity & Electronics - QMED

70% to pass

In a 15 HP induction-type motor with a squirrel-cage rotor, compared to the full load current at rated speed, how much starting current is required at standstill to produce successful starting torque?

Ahalf the full load current
Bequal to the full load current
Cfive times the full load current
Dten to twenty times the full load current
AI Explanation

The correct answer is C) five times the full load current. In an induction-type motor with a squirrel-cage rotor, a significantly higher starting current is required to overcome the high initial resistance and produce the necessary starting torque. At standstill, the motor's rotor is stationary, resulting in a low reactance and a high resistive component. This combination requires a much higher current, typically 5 times the full load current, to generate the required starting torque. The other options are incorrect because: A) half the full load current would be insufficient to produce the necessary starting torque; B) equal to the full load current would also be insufficient; and D) ten to twenty times the full load current, while possible, is generally not required for successful starting in a 15 HP induction-type motor.

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