Question 136Electricity & Electronics - QMED

The correct answer is B) push the stop button to de-energize the "M" coil. When a motor fails to start and gives a loud hum, it indicates that the motor windings are energized but the rotor is not turning. This is likely due to a fault in the motor or the starting circuit. The best first action is to de-energize the motor by pushing the stop button, which will cut power to the "M" coil and the motor windings. This will prevent further damage to the motor and allow you to diagnose the issue safely. The other options are incorrect because: A) disassembling the motor is not the first step and could further damage the equipment; C) resetting the thermal overload does not address the root cause of the issue; and D) holding the "M" contactor closed manually is unsafe and could lead to electrical shock hazards.