Electrical Maintenance Department Interview Questions and Answers

DC motors use direct current to generate rotational motion, while AC motors use alternating current.

• DC motors have a commutator and brushes to switch the current direction, while AC motors do not.

• AC motors are more commonly used in household appliances, while DC motors are used in electric vehicles and industrial machinery.

• Examples of DC motors include brushed and brushless motors, while examples of AC motors include induction and synchronous motors.

The motor in a DOL starter is purposefully started to provide power to the connected equipment.

• The motor in a DOL (Direct-On-Line) starter is started to provide power to the connected equipment without any soft start or speed control.

• The purpose of starting the motor in a DOL starter is to directly connect it to the power supply for immediate operation.

• This type of starter is commonly used for small motors where the starting current is not a concern.

I studied various subjects related to electrical engineering in my college.

• Electrical Machines

• Power Electronics

• Control Systems

• Electrical Measurements and Instrumentation

• Electromagnetic Theory

• Digital Electronics

• Microprocessors and Microcontrollers

• Power Systems

• Renewable Energy Sources

• Electrical Circuit Analysis

A Dol starter diagram is used to start and stop a motor by providing direct online starting.

• Dol starter consists of a contactor, overload relay, start and stop push buttons, and power supply connections.

• When the start button is pressed, the contactor closes and supplies power directly to the motor.

• The overload relay protects the motor from overheating by tripping if the current exceeds a set limit.

• The stop button opens the contactor and stops the motor.

• Dol starters are common...read more