Electrical Engineering Concepts

State two transmission voltages.

• 110kV and 220kV

• 275kV and 400kV

• 500kV and 750kV

• 150kV and 300kV

Give two distribution voltages.

• 110V and 220V

• 230V and 400V

• 240V and 380V

• 120V and 240V

What does 10KA represent on an MCB to BS 60898?

• The maximum voltage rating of the MCB.

• The breaking capacity of the MCB.

• The current rating of the MCB.

• The insulation resistance of the MCB.

Why have a switch disconnector prior to the inverter in a PV installation?

• To ensure safety and allow maintenance.

• To increase the efficiency of the inverter.

• To reduce the cost of installation.

• To improve the aesthetic appearance of the system.

Sketch and label a Step Up Transformer.

• A transformer that decreases voltage.

• A transformer that increases voltage.

• A transformer that converts AC to DC.

• A transformer that stores electrical energy.

Describe the purpose of the Start Capacitor in a capacitor start and run single phase motor.

• To provide an initial boost of energy to start the motor.

• To regulate the speed of the motor during operation.

• To reduce electrical noise in the motor circuit.

• To improve the efficiency of the motor at high speeds.

State TWO advantages of an LED lamp.

• Energy efficiency and long lifespan.

• High heat generation and short lifespan.

• Low cost and high energy consumption.

• Limited color options and high maintenance costs.

Sketch and label a Step Down Transformer.

• A transformer that increases voltage.

• A transformer that reduces voltage.

• A transformer that stores energy.

• A transformer that converts AC to DC.

What may the lighting effect be called if a rotating machine appears stationary while in use, using discharge lights?

• Stroboscopic effect

• Optical illusion

• Motion blur

• Persistence of vision

What is the function of a Thermal Overload in a DOL starter?

• To protect the motor from overheating.

• To increase the motor's efficiency.

• To reduce electrical noise in the circuit.

• To provide additional torque during startup.