The space left between the piston and the valve plate of a reciprocating compressor when the piston is at the top of the cylinder is called:
A) The bore. B) The stroke.
C) The clearance volume. D) The mechanical allowance.
[Ques. 2] The most common types of defrost for commercial refrigeration evaporators are:
A) Reverse cycle and air defrost. B) Electric and hot-gas defrost.
C) Inductive and ultrasonic defrost. D) Mechanical and hydraulic.
[Ques. 3] What color hose connects to the low side of the system, allowing the compound gauge to read the system low-side pressure?
A) Blue B) Red C) Black D) Yellow
[Ques. 4] How does a two-step scroll compressor achieve capacity reduction?
A) The orbiting scroll only completes half-orbits in low-capacity operation.
B) The orbiting scroll turns clockwise for reduced capacity and counterclockwise for full capacity.
C) An internal rotating plate opens and closes two drilled ports in the scroll.
D) Only one scroll is used during low-capacity operation, while both are used for full-capacity operation.
[Ques. 5] An advantage of open-drive compressors is that:
A) They are smaller and more compact than hermetic compressors.
B) They are generally less expensive than comparable semihermetic compressors.
C) They require no type of regular maintenance.
D) The motor and compressor can be replaced separately.
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