Ch 5

There are no physical electrical connections between the stator and the rotor

• T

• F

Single-phase motors are the most common 3-phase motors used in industry today.

• T

• F

The shorting bars are mounted on a shaft that is used to transfer the power to the load.

• T

• F

The main difference between different types of 3-phase motors is the design of the rotors and windings.

• T

• F

A squirrel-cage motor is the most common design for induction-motor rotor design.

• T

• F

In design A motors the locked-rotor current is about 500% to 1000% of full load current.

• T

• F

Because of the high resistance and high slip, Design B motors are less efficient than other designs.

• T

• F

Design A motors are suitable for equipment with high-inertia starts, such as positive-displacement pumps and heavily loaded conveyors.

• T

• F

In an induction motor, the shorted secondary in the rotor carries the induced secondary current.

• T

• F

A rotor always rotates at exactly the correct speed to induce the current required to develop the torque necessary to drive the load.

• T

• F