Question 307Electricity/Electronics - QMED70% to pass
As shown in the illustration, if the line voltage is 450 VAC, what would be the applied voltage to the motor at the instant of startup and through the acceleration period? Illustration EL-0012
AI Explanation
The correct answer is B) 292 VAC.
During motor startup and acceleration, the applied voltage to the motor is typically reduced to a lower value, often around 60-65% of the line voltage. This is done to limit the high inrush current that can occur when a motor is started directly on-line. The reduced voltage helps to smoothly accelerate the motor to its operating speed.
In this case, with a line voltage of 450 VAC, the applied voltage to the motor would be approximately 292 VAC (450 VAC x 0.65 = 292 VAC), which is the correct answer.
The other options are incorrect because:
A) 225 VAC is too low and would not provide enough torque for proper motor acceleration.
C) 360 VAC is higher than the typical reduced voltage range.
D) 450 VAC is the full line voltage, which is not the applied voltage during startup and acceleration.
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