Question 289Electricity & Electronics - QMED

70% to pass

In using a portable growler for the purpose of locating a shorted stator coil in an AC motor as shown in the illustration, what statement is true as the feeler is moved from slot to slot around the stator? Illustration EL-0200

Diagram for USCG Electrical QMED: In using a portable growler for the purpose of locating a shorted stator coil...

AThe feeler will vibrate in synchronism with the 60 Hz AC power source and produce a growling noise when the feeler is moved over a slot which does NOT contain a shorted coil.

BThe feeler will vibrate in synchronism with the 60 Hz AC power source and produce a growling noise when the feeler is moved over a slot containing an open coil.

CThe feeler will remain motionless with NO vibration or noise when the feeler is moved over a slot containing a shorted coil.

DThe feeler will vibrate in synchronism with the 60 Hz AC power source and produce a growling noise when the feeler is moved over a slot containing a shorted coil.

AI Explanation

The correct answer is D. The feeler will vibrate in synchronism with the 60 Hz AC power source and produce a growling noise when the feeler is moved over a slot containing a shorted coil. This is because a shorted stator coil creates a localized magnetic field that interacts with the alternating current in the feeler, causing it to vibrate and produce a distinctive growling noise. The other options are incorrect because: A) The vibration and noise occur when the feeler is over a shorted coil, not a non-shorted coil. B) An open coil would not produce the same effect as a shorted coil. C) The feeler does not remain motionless when over a shorted coil, but rather vibrates and produces a growling noise.