General Motors Electrical Maintenance Team Lead Interview Questions and Answers for Experienced

A circuit breaker is an electrical switch that automatically interrupts the flow of current when it exceeds a certain limit.

• It is used to protect electrical circuits from damage caused by overloading or short circuits.

• It works by detecting the excess current and tripping the switch to break the circuit.

• It can be reset manually or automatically depending on the type of circuit breaker.

• Examples include thermal circuit br...read more

A contactor is an electrical switch used for switching an electrical circuit on or off.

• It is used to control electric motors, lighting, heating, and other electrical loads.

• It consists of a coil, contacts, and an enclosure.

• The coil generates a magnetic field that pulls the contacts together to close the circuit.

• Examples include HVAC systems, elevators, and industrial machinery.

• Contactor ratings are based on the amount o...read more

MCB stands for Miniature Circuit Breaker. It is an electrical switch that automatically shuts off the electrical circuit during an overload or short circuit.

• MCB is a type of circuit breaker that is commonly used in residential and commercial buildings.

• It is designed to protect electrical circuits from damage caused by overloading or short circuits.

• MCBs are available in different current ratings and can be easily replac...read more

A motor is a device that converts electrical energy into mechanical energy to produce motion.

• Motors are used in various applications such as electric vehicles, industrial machinery, and household appliances.

• There are different types of motors such as DC motors, AC motors, stepper motors, and servo motors.

• The basic principle of a motor is the interaction between a magnetic field and an electric current.

• Examples of motor...read more

A current transformer is a device that measures the current flowing in a circuit by producing a proportional current in its secondary winding.

• Consists of a primary winding and a secondary winding

• Primary winding is connected in series with the circuit carrying the current to be measured

• Secondary winding is connected to a measuring instrument or protective relay

• Produces a current in the secondary winding that is proporti...read more

A diesel generator works by converting diesel fuel into mechanical energy which is then converted into electrical energy.

• Diesel fuel is injected into the combustion chamber where it ignites and creates high pressure gases that push the piston down, creating mechanical energy.

• The mechanical energy is then converted into electrical energy through the use of an alternator.

• The alternator uses a magnetic field and a conduct...read more

A diesel engine works by compressing air in the cylinder, which heats up and ignites the fuel injected into the cylinder.

• Air is drawn into the cylinder and compressed by the piston

• The compressed air heats up and ignites the fuel injected into the cylinder

• The explosion pushes the piston down, which turns the crankshaft and powers the engine

• Diesel engines are more efficient than gasoline engines because they compress the...read more

A train doesn't need a differential because its wheels are fixed to the same axle and rotate at the same speed.

• Train wheels are fixed to the same axle

• Wheels rotate at the same speed

• Differential is used in vehicles with wheels that rotate at different speeds

• Differential allows for smooth turning

Petrol engines have lower compression ratios compared to diesel engines.

• Petrol engines have lower compression ratios to prevent knocking or detonation.

• Diesel engines have higher compression ratios to ignite the fuel without spark plugs.

• Higher compression ratios in diesel engines result in better fuel efficiency and torque.

• Petrol engines require lower compression ratios to accommodate the lower octane rating of petrol f...read more