Question 1

Many of the larger air conditioning units use a splash system for the compressor.

Accepted Answer

Larger air conditioning units typically use a more efficient refrigeration cycle involving compression, condensation, expansion, and evaporation, rather than a splash system, which is more rudimentary and not suitable for the demands of large-scale cooling.

Question 2

The differential pressure control permits the cut-in and cut-out points to be set.

Accepted Answer

The differential pressure control allows for the adjustment of the pressure at which the system turns on and off, allowing for the cut-in and cut-out points to be set.

Question 3

The oil-pressure failure switch actually contains several control functions in the same unit.

Accepted Answer

The oil-pressure failure switch typically includes functions such as shutting down the engine, activating a warning light or alarm, and preventing the engine from starting until oil pressure is restored.

Question 4

The time-delay circuit consists of a current-limiting resistor, a resistance heating element, and a ____.&#10;A) constant resistor&#10;B) bimetal strip&#10;C) flip-flop&#10;D) variable transistor

Accepted Answer

A bimetal strip is commonly used in time-delay circuits. It is composed of two metals with different coefficients of thermal expansion bonded together, which causes the strip to bend when exposed to heat. This bending can be used to trigger a switch and create a time delay. The current-limiting resistor and resistance heating element are also necessary components, but they are not exclusive to time-delay circuits and may be used in other types of circuits as well. The constant resistor and variable transistor are not typically used in time-delay circuits.

Question 5

The oil-pressure failure switch functions include a differential pressure switch, a timer, and a(n) ____.&#10;A) pressure relief valve&#10;B) oil cooler&#10;C) set of control contacts&#10;D) oil pick-up pump

Accepted Answer

The oil-pressure failure switch functions include a differential pressure switch, which measures the difference between oil pressure in the engine and a reference pressure such as atmospheric pressure. When the differential pressure reaches a certain value, the switch actuates a set of control contacts. In some cases, there may also be a timer involved to prevent false alarms or to ensure proper response time. A pressure relief valve, oil cooler, or oil pick-up pump are not necessarily part of the oil-pressure failure switch functions.

Question 6

Most pressure failure switches are designed to be used on 240- or 480-volt connections.

Accepted Answer

Most pressure failure switches are designed to be used in systems to monitor and respond to pressure changes rather than being directly related to specific voltage levels like 240 or 480 volts. They are more about sensing pressure conditions than being designed for specific electrical voltages.

Question 7

The actual oil pressure in a compressor is the difference in pressure between the suction pressure and the ____ of the oil pump.&#10;A) discharge pressure&#10;B) impact pressure&#10;C) gauge pressure&#10;D) velocity pressure

Accepted Answer

The oil pressure in a compressor is determined by the difference in pressure between the suction pressure and the discharge pressure of the oil pump.

Question 8

Most reciprocating compressors operate with an oil pressure of ____.&#10;A) 15 to 25 psi&#10;B) 25 to 35 psi&#10;C) 35 to 45 psi&#10;D) 45 to 55 psi

Accepted Answer

The answer of Most reciprocating compressors operate with an oil...

Question 9

The control contacts are connected in series with the motor starter coil to the compressor.

Accepted Answer

The control contacts are connected in series with the motor starter coil to the compressor.

Question 10

Oil-pressure failure switches are generally set to cut in at about 18 psi and to cut out at about ____.&#10;A) 6 psi&#10;B) 8 psi&#10;C) 10 psi&#10;D) 12 psi

Accepted Answer

The answer of Oil-pressure failure switches are generally set to...

Deck 34: The Oil-Pressure Failure Switch