EEE Quiz 4

Which method of speed control for induction motors involves changing the supply frequency?

• Stator voltage control

• Rotor resistance control

• Pole changing method

• Variable frequency control

In the slip power recovery scheme for induction motors, the recovered power from the rotor circuit is:

• Dissipated as heat

• Stored in capacitors

• Fed back to the supply

• Used to drive auxiliary equipment

The Kramer system is an example of:

• Stator voltage control

• Slip power recovery scheme

• Pole changing method

• Plugging

The speed of an induction motor can be controlled below synchronous speed by:

• Adding external resistance to the stator circuit

• Adding external resistance to the rotor circuit

• Reducing supply voltage

• Increasing supply frequency

In a voltage source inverter (VSI) control of induction motors, what is controlled to vary the speed?

• Only voltage

• Only frequency

• Both voltage and frequency

• Slip

The principle of operation of slip power recovery scheme is based on:

• Converting mechanical power to electrical power

• Recovering slip power that would otherwise be wasted as heat

• Increasing the number of poles

• Changing stator voltage

Which speed control method for induction motors offers speed control above synchronous speed?

• Rotor resistance control

• Stator voltage control

• Slip power recovery scheme

• Variable frequency with V/f less than rated

A 3-point starter for DC motors contains:

• Starting resistance, no-volt release, and overload release

• Starting resistance, no-volt release, and field regulator

• Starting resistance, overload release, and field regulator

• No-volt release, overload release, and field regulator

The main advantage of a 4-point starter over a 3-point starter for DC motors is:

• Higher starting torque

• Protection against field failure

• Better speed regulation

• Lower cost

In plugging of a DC motor, the armature terminals are:

• Short-circuited

• Connected to a resistance

• Reversed

• Disconnected from supply