Q-01 FDNY Exam – Questions and Answers |Verified 100% Correct|

Q-01 FDNY Exam – Questions and Answers |Verified 100% Correct| One characteristic of a synchronous motor is that it operates at A) high starting torque B) constant speed C) causes lagging power factor D) all of the above - ANSWER -B) constant speed If during does not occur in a refrigerating system, what is the result? A) High-head pressure B) Low-condenser pressure C) Low-head pressure D) None of the above - ANSWER -A) High-head pressure A wound-rotor induction motor with external resistance is a A) multispeed motor B) constant-speed motor C) single-speed motor D) waterproof cover - ANSWER -A) multispeed motor In a Freon refrigerating system in which all piping is made up of hard copper fittings and streamlined "wrought"-type fittings, the joints should be A) screwed B) soldered or brazed C) flanged with ground faces D) flanged with lined rubber gaskets - ANSWER -B) soldered or brazed If any piece of equipment can be isolated as a separate unit A) A gauge must be present B) a safety valve must be installed C) valves must be locked D) the system must be able to run without it - ANSWER -B) a safety valve must be installed On a 220 volt, three phase, 4-wire electric service, any line will read A) 220 volts B) 440 volts C) 70 volts D) 110 volts - ANSWER -D) 110 volts If the specific heat of glass is .196, how many btu are needed to raise the temperature of 10 pounds of glass from 50° F to 70°F? A) 40.2 B) 39.2 C) 59.2 D) 36.2 - ANSWER -B) 39.2 A direct expansion (bare) coil evaporator is used to maintain a meat storage space at 28 to 30° F. The last coil has no frost. It can be said that this system is A) condition is acceptable to maintain a high plant efficiency B) is a direct indication of air in the system C) indicates moisture in the refrigerant D) is a direct indication that the coil is being starved - ANSWER -D) is a direct indication that the coil is being starved Fuses and circuit breakers are safety devices for electric motors but they will not protect motors against A) short circuit B) heavy overload C) burnout D) overheating - ANSWER -D) overheating Sodium chloride is not used when the temperature is A) -20° F B) 10° F C) 5° F D) 0° F - ANSWER -A) -20° F The speed of a six-pole, 50-cycle motor is A) 600 RPM B) 1000 RPM C) 1800 RPM D) 3600 RPM - ANSWER -B) 1000 RPM The rated discharge capacity of the pressure-relief device or fusible plug for a refrigerant-containing vessel is determined by the formula C = Fd1. "C" equals A) btu/minute B) refrigerant pressure C) air in pounds/minute D) cubic feet/minute - ANSWER -C) air in pounds/minute In an automatically operated, flooded shell-and-tube cooler, an electric float switch is used primarily to A) control the flow of brine into the tubes B) control the flow of refrigerant into the shell C) purge the oil from the cooler D) purge non-condensable gas from the cooler - ANSWER -B) control the flow of refrigerant into the shell What are three reasons why compressors short cycle? - ANSWER -1. Leaky solenoid valve 2. Dirty or iced evaporator 3. Lack of refrigerant Find the volume of a cylinder 8" in diameter with a 10" stroke. How much water can be put in this cylinder? - ANSWER -V = πR2 x L V = 3.14 x 42 x 10 V = 3.14 x 16 x 10 V = 3.14 x 160 V = 502.4 cubic inches In order to vary the specific capacity of an absorption refrigerating plant, an operating engineer should regulate the A) Flow of steam to the generator, and adjust the expansion valve. B) Relief valves on the generator, and the speed of the NH2 pump. C) Speed of the absorber pump. D) Flow of water to the condenser. - ANSWER -A) Flow of steam to the generator, and adjust the expansion valve. The refrigerant least miscible in oil is A) CO2 B) R-12 C) R-40 D) R-141 - ANSWER -A) CO2 The first sign that the drum of ammonia refrigerant is almost empty is