Question 1

In most instances, the rated-load current is at least equal to 64.1 percent of the hermetic refrigerant motor-compressor's ____ current.

Accepted Answer

The rated-load current is typically defined as the current at which the motor-compressor operates under full-load conditions. Therefore, it is logical that the rated-load current would be at least equal to the maximum continuous current rating of the motor-compressor. Choices B, C, and D are not relevant or appropriate in this context.

Question 2

The current draw of a precipitator is ____.

Accepted Answer

While the current draw of a precipitator is not zero, it is typically very low. This is because the voltage applied to the precipitator creates an electric field that attracts the charged particles in the gas stream. Once the particles are collected, they form a layer on the precipitator's plates, which reduces the current draw even further. The current draw may increase slightly when there is higher pollution levels, but it is still generally very low.

Question 3

The manufacturer determines the ____ by multiplying the rated-load current, or the branch-circuit selection current of the hermetic refrigerant motor-compressor, by 125 percent.

Accepted Answer

D

Question 4

What precautions must be taken when installing drive belts?

Accepted Answer

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Question 5

When hermetic refrigerant motor-compressors are designed to operate continuously at currents greater than 156 percent of the rated-load current, the nameplate is marked with ____ current.

Accepted Answer

The answer of When hermetic refrigerant motor-compressors are designed to...

Question 6

The correct tension for a belt in the cooling unit drive can be determined from the ____.

Accepted Answer

The correct tension for a belt in the cooling unit drive can be determined from the motor manufacturer's literature, which provides specific instructions for proper belt tensioning. It is important to follow these instructions to ensure efficient and reliable operation of the motor and cooling unit. The maximum continuous current, rated-load current, and nameplate do not provide information about belt tension.

Question 7

Low-pressure refrigerant flows through the ____ to provide cooling for the motor of a hermetically sealed compressor.

Accepted Answer

The answer of Low-pressure refrigerant flows through the ____ to...

Question 8

Whenever the specific area is cooled to the desired temperature, a(n) ____ opens the control circuit to the motor controller and the air movement stops until the area again requires cooling.

Accepted Answer

A thermostat is a device that senses temperature and controls the operation of a heating or cooling system. In this scenario, the thermostat is controlling the operation of the air movement system by opening the control circuit to the motor controller, which in turn stops the air movement until the area again requires cooling.

Question 9

How are pollutants actually trapped by the precipitator?

Accepted Answer

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Question 10

The exhaust blower unit consists of a three-horsepower, three-phase, 208-volt motor driving a propeller-type fan through a(n) ____ drive.

Accepted Answer

The answer of The exhaust blower unit consists of a...

Question 11

The ____ current is determined by the manufacturer of the hermetic refrigerant motor compressor by testing at rated refrigerant pressure, temperature conditions, and voltage.

Accepted Answer

The rated-load current is the current that the manufacturer determines by testing the compressor at specific operating conditions, including rated refrigerant pressure, temperature, and voltage. This current is typically used to determine the appropriate size of the wire and circuit breaker.

Question 12

In the precipitator, wires made of which metal give the particles a positive charge?

Accepted Answer

According to commonly used designs of electrostatic precipitators, corona wires which give particles a positive charge are typically made of tungsten.

Question 13

What is the basic construction of a precipitation unit?

Accepted Answer

The answer of What is the basic construction of a...

Question 14

The main parts of a precipitator are the ____, collector cells, and power supply.

Accepted Answer

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Question 15

What overload protection is required for the motors of the fan coil units in the cooling equipment?

Accepted Answer

The answer of What overload protection is required for the...

Question 16

One method of removing oil mist is by the use of ____ units.

Accepted Answer

Oil mist can be effectively removed by precipitation units, which use various mechanisms such as electrostatic precipitation, impingement on surfaces, and centrifugal separation to collect and remove the mist from the air stream. Coolant units are used to cool machinery and do not serve the same purpose as oil mist removal. Rotor and stator are parts of machines and are not relevant for oil mist removal.

Question 17

What is the maximum deflection force in pounds for a belt in the cross-section class D?

Accepted Answer

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Question 18

What is oil mist and why is it detrimental?

Accepted Answer

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Question 19

A(n) ____ converts high-voltage ac into high-voltage dc.

Accepted Answer

A rectifier circuit is used to convert high-voltage AC to high-voltage DC by allowing only one half of the AC waveform to pass through while blocking the other half. This results in a pulsating DC voltage that can be smoothed out using capacitors. Transistors, capacitors, and inductors are components used in electronic circuits but do not specifically perform the function of converting AC to DC.

Question 20

The ____ protective device is determined by multiplying the rated-load current, or the branch-circuit selection current of the hermetic refrigerant motor-compressor, by 225 percent and then adding all concurrent loads such as electric heaters, motors, and so on.

Accepted Answer

The answer of The ____ protective device is determined by...

Quiz 12: Ventilating Air Conditioning and Other Facilities