Controls

Question 1

The run windings of a motor have _____ turns as compared to the start windings.

Answer 1

fewer

Question 2

On a typical split-phase electric motor the start winding circuit is deenergized as it reaches approximately ____ of its operating speed?

Answer 2

75%

Question 3

What component wired in series with the start windings on a single phase motor will create greater starting torque.

Answer 3

a capacitor

Question 4

A three-phase motor does not have

Answer 4

A. start windings
B. a start capacitor
C a start relay

Question 5

A start component that is rated in microfarad would be a

Answer 5

capacitor

Question 6

What effect will a higher supply voltage have on the current draw of an electric motor?

Answer 6

it will be higher than it should be

Question 7

With an electric motor running normally the amperage reading would be called?

Answer 7

run-load amperage

Question 8

If a technician uses an ohm meter to check the windings of an electric motor and records an infinite reading on the start windings this would indicate?

Answer 8

the start winding circuit has an open somewhere

Question 9

What device would be discharged using a 20,000-ohm, 5 watt resistor?

Answer 9

capacitor

Question 10

The run-load amperage on an electric motor is typically

Answer 10

1/5 that of a full-load amperage

Question 11

What device is used to energize another load such as a contactor or motor starter with in turn would start or stop a motor.

Answer 11

a pilot duty relay

Question 12

A magnetic coil and electrical contacts are the primary components of this electrical device?

Answer 12

a contactor

Question 13

A magnetic coil, overload protector and electrical contactors are the primary components of this electrical device

Answer 13

a motor starter

Question 14

An electric motor that has an internal overload would have a?

Answer 14

a thermal device buried in the motor windings

Question 15

What device could be used as external protection for a motor?

Answer 15

A. a line fuse
B. a circuit breaker
C. an external overload

Question 16

What type of motor would a technician switch any two legs on to reverse the rotation of the motor?

Answer 16

Three Phase

Question 17

A technician could install this type of component on a refrigeration system that has multiplexed circuits to

Answer 17

prevent the evaporator temperature on a multiplexed system from falling too low

Question 18

A technician would set this device by the RLA on the refrigeration compressors

Answer 18

crankcase pressure regulator

Question 19

A technician would set this device by calculating the evaporator superheat

Answer 19

thermal expansion device

Question 20

What device is used to reduce the suction temperature of the compressor?

Answer 20

desuperheating TXV

Question 21

If a technician needs to control the head pressure on a refrigeration unit within tight limits the best device to employ on the condenser fan motor would be?

Answer 21

a variable frequency drive (VFD)

Question 22

The EPR valve is installed between the?

Answer 22

suction accumulator and the compressor
and
evaporator and the suction accumulator

Question 23

Which of these devices would be considered a low ambient temperature head pressure control used on an outdoor unit?

Answer 23

fan cycling

Question 24

If a technician wanted to protect a refrigeration system from operating
under excessive head pressure situations he would install a/an

Answer 24

head pressure control

Question 25

The following device would use a pressure transducer to sense net oil pressure, electronic oil safety controllers use a

Answer 25

electronic oil safety control

Question 26

If a technician needed high accuracy it would be best to select a device
that employed the following sensing element if available

Answer 26

a thermistor

Question 27

If a technician installed a low-pressure switch, a liquid line solenoid valve, and a thermostat in a
refrigeration system what kind of circuit would have been designed?

Answer 27

automatic pump down cycle