IDA201 Unit 17 Review (MT) pt.1 (CRF) - Mr. Graham

The two popular operating voltages for residences are__________V and__________V.

• 115 and 230

• 208 and 240

• 125 and 277

• 120 and 208

When an open motor gets up to speed, the__________switch takes the start winding out of the circuit.

• centrifugal

• relay

• delay

• electrostatic

The resistance in the start winding is _________ than the resistance in the run winding?

• lesser

• greater

Which of the following devices may be wired into the starting circuit of a motor to improve the starting torque?

• Another winding

• A start capacitor

• A thermostat

• A switch

Which of the following devices may be wired into the running circuit of a motor to improve the running efficiency?

• A start capcitor

• A start and run capacitor

• A run capacitor

• None are correct

Define BEMF

• This is the resistant-effect of an electric motor’s rotor turning within the motor.

• This is the amperage-generating effect of an electric motor’s rotor turning within the motor.

• This is the voltage-generating effect of an electric motor’s rotor turning within the motor.

• None are correct

Why is the hermetic compressor motor manufactured from special materials?

• They must be compatible with the refrigerant and minerals used in the refrigeration system.

• They must be compatible with the refrigerant and oils used in the refrigeration system.

• They must be free of contaminants in the coil of the system.

• They may not be compatible with the system.

How does power pass through the compressor shell to the motor inside?

• Through the refrigerant.

• Through the motor tubes.

• Through insulated motor terminals

• Through the relay device.

The two types of relays used to start hermetic compressors are the​ and ​ relay.

• potential
• current
• thermal
• single conductor

A PTC device is used​ (a)  

• to start a hermetic compressor.
• as a motor protector.
• to protect against low oil pressure.
• to protect against high oil temperature.