Electricity for Refrigeration, Heating, and Air Conditioning (MindTap Course List)
10th Edition
ISBN: 9781337399128
Author: Russell E. Smith
Publisher: Cengage Learning
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Textbook Question
Chapter 1, Problem 7RQ
Which of the following is the standard by which electrical installations are measured in the United States?
- a. National Electrical Code®
- b. United Electrical Code®
- c. Basic Electrical Code®
- d. none of the above
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9. Design a spur gear drive required to transmit 45 kW at a pinion speed of 800 r.p.m. The velocity ratio
is 3.5 : 1. The teeth are 20° full-depth involute with 18 teeth on the pinion. Both the pinion and gear
are made of steel with a maximum safe static stress of 180 MPa. Assume a safe stress of 40 MPa for
the material of the shaft and key.
10. Design a pair of spur gears with stub teeth to transmit 55 kW from a 175 mm pinion running at 2500
r.p.m. to a gear running at 1500 r.p.m. Both the gears are made of steel having B.H.N. 260. Approximate
the pitch by means of Lewis equation and then adjust the dimensions to keep within the limits set by
the dynamic load and wear equation.
7. A motor shaft rotating at 1440 r.p.m. has to transmit 15 kW to a low speed shaft rotating at 500 r.p.m.
The teeth are 20° involute with 25 teeth on the pinion. Both the pinion and gear are made of cast iron
with a maximum safe stress of 56 MPa. A safe stress of 35 MPa may be taken for the shaft on which
the gear is mounted. Design and sketch the spur gear drive to suit the above conditions. The starting
torque may be assumed as 1,25 times the running torque.
Ruins 20 LW at 100 nm to another shaft running approxi
6.
A two stage reduction drive is to be designed to transmit 2 kW; the input speed being 960 r.p.m. and
overall reduction ratio being 9. The drive consists of straight tooth spur gears only, the shafts being
spaced 200 mm apart, the input and output shafts being co-axial.
Chapter 1 Solutions
Electricity for Refrigeration, Heating, and Air Conditioning (MindTap Course List)
Ch. 1 - True or False: A heating and air-conditioning...Ch. 1 - What is a live electrical circuit?Ch. 1 - Which of the following voltages will a...Ch. 1 - Electrical shock occurs when a person _________....Ch. 1 - What are the important elements of electrical...Ch. 1 - Prob. 6RQCh. 1 - Which of the following is the standard by which...Ch. 1 - Prob. 8RQCh. 1 - What type of ladder should the technician use on...Ch. 1 - What precautions should be taken when you see a...
Ch. 1 - True or False: It is recommended that at least one...Ch. 1 - True or False: The correct fuse size for an...Ch. 1 - What is the difference between a two-prong plug...Ch. 1 - Which prong on a three-prong plug is the ground?...Ch. 1 - True or False: A grounding adapter does no good if...Ch. 1 - An electrical device that will open an electrical...Ch. 1 - True or False: Receptacles used on the job site...Ch. 1 - What precautions should you use when working in an...Ch. 1 - What is the difference between a fuse and a...Ch. 1 - List at least five electrical safety rules that...
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