Refrigeration and Air Conditioning Technology (MindTap Course List)
8th Edition
ISBN: 9781305578296
Author: John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson
Publisher: Cengage Learning
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Chapter 28, Problem 15RQ
Why is two-stage compression popular for extra-low-temperature refrigeration systems?
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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.
2 A metal block of mass m = 10 kg is sliding along a frictionless surface with an initial speed
Vo, as indicated below. The block then slides above an electromagnetic brake that applies a
force FEB to the block, opposing its motion. The magnitude of the electromagnetic force
varies quadratically with the distance moved along the brake (x):
10
FEB = kx²,
with k
= 5
N
m²
V₁ = 8 m/s
m = 10 kg
FEB
Frictionless surface
Electromagnetic brake
⇒x
Determine how far the block slides along the electromagnetic brake before stopping, in m.
Chapter 28 Solutions
Refrigeration and Air Conditioning Technology (MindTap Course List)
Ch. 28 - List the evaporating temperatures for liquid...Ch. 28 - Prob. 2RQCh. 28 - Prob. 3RQCh. 28 - Prob. 4RQCh. 28 - Prob. 5RQCh. 28 - Prob. 6RQCh. 28 - Prob. 7RQCh. 28 - Which are power supplies used for truck...Ch. 28 - What type of reserve capacity does truck...Ch. 28 - Why is truck refrigeration designed to provide...
Ch. 28 - How is the air distributed over the cargo in truck...Ch. 28 - Name two types of engines used for truck...Ch. 28 - Prob. 13RQCh. 28 - Truck trailers with their own refrigeration...Ch. 28 - Why is two-stage compression popular for...Ch. 28 - An R-404A system is operating with a -50F...Ch. 28 - Describe cascade refrigeration and tell why more...Ch. 28 - Why is a circulating brine system more attractive...Ch. 28 - Two methods used to power refrigeration...
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