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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Chapter 5, Problem 5RQ
To determine
The major difference between a contactor and a relay.
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If the rods are made from a square section with the dimension as shown. Calculate the load
that will make point A move to the left by 6mm, E=228GPa.
2P-
P
A
80mm
B
200mm
2P
0.9m
1.3m
3.
9.
10.
The centrifugal tension in belts
(a) increases power transmitted
(b) decreases power transmitted
(c) have no effect on the power transmitted
(d) increases power transmitted upto a certain speed and then decreases
When the belt is stationary, it is subjected to some tension, known as initial tension. The value of this
tension is equal to the
(a) tension in the tight side of the belt
(b) tension in the slack side of the belt
(c) sum of the tensions in the tight side and slack side of the belt
(d) average tension of the tight side and slack side of the belt
The relation between the pitch of the chain (p) and pitch circle diameter of the sprocket (d) is given by
60°
(a) p=d sin
(c) p=d sin
(120°
T
where T Number of teeth on the sprocket.
90°
(b) p=d sin
T
180°
(d) p=d sin
T
OBJECTIVE TYPE QUESTIONS
1.
The maximum fluctuation of energy is the
2.
(a) sum of maximum and minimum energies
(b) difference between the maximum and minimum energies
(c) ratio of the maximum energy and minimum energy
(d) ratio of the mean resisting torque to the work done per cycle
In a turning moment diagram, the variations of energy above and below the mean resisting torque line
is called
(a) fluctuation of energy
(b) maximum fluctuation of energy
(c) coefficient of fluctuation of energy
(d) none of the above
Chapter 16: Turning Moment Diagrams and Flywheel 611
The ratio of the maximum fluctuation of speed to the mean speed is called
3.
(a) fluctuation of speed
(c) coefficient of fluctuation of speed
4.
(b) maximum fluctuation of speed
(a) none of these
The ratio of the maximum fluctuation of energy to the.......... is called coefficient of fluctuation of
energy.
(a) minimum fluctuation of energy
(b) work done per cycle
The maximum fluctuation of energy in a flywheel is equal to
5.…
Chapter 5 Solutions
Electricity for Refrigeration, Heating, and Air Conditioning (MindTap Course List)
Ch. 5 - What are the three types of electrical diagrams...Ch. 5 - A load is an electrical device that __________. a....Ch. 5 - What is the major load of an air-conditioning...Ch. 5 - Identify the following symbols for loads:Ch. 5 - Prob. 5RQCh. 5 - What do the terms normally open and normally...Ch. 5 - What is the difference between a magnetic starter...Ch. 5 - Prob. 8RQCh. 5 - Draw a heating and a cooling thermostat and...Ch. 5 - A three-pole contactor would allow how many paths...
Ch. 5 - A disconnect switch is used to __________. a. open...Ch. 5 - What determines whether a pressure switch opens or...Ch. 5 - Identify the following symbols for...Ch. 5 - What is the difference between a thermal overload...Ch. 5 - What is the purpose of a transformer? Draw the...Ch. 5 - Which of the following is not a requirement for an...Ch. 5 - What is the purpose of a legend on a schematic...Ch. 5 - A factual diagram is _____. a. a pictorial diagram...Ch. 5 - Identify the following symbols for safety devices.Ch. 5 - Prob. 20RQCh. 5 - True or False: The schematic diagram tells service...Ch. 5 - What is the difference between a pilot duty and a...Ch. 5 - What type of switch would be used to open or close...Ch. 5 - What is the purpose of a fuse in an electrical...Ch. 5 - True or False: A solenoid valve is a device that...Ch. 5 - What is a signal light used for in a control...Ch. 5 - Change the following normally open elements from...Ch. 5 - Draw the symbols for the following electrical...Ch. 5 - Add letter designations to the symbols to indicate...Ch. 5 - Draw a symbol for a magnetic starter.
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- OBJECTIVE TYPE QUESTIONS 1. The velocity ratio of two pulleys connected by an open belt or crossed belt is 2. (a) directly proportional to their diameters (b) inversely proportional to their diameters (c) directly proportional to the square of their diameters (d) inversely proportional to the square of their diameters Two pulleys of diameters d, and d, and at distance x apart are connected by means of an open belt drive. The length of the belt is (a)(d+d₁)+2x+ (d₁+d₂)² 4x (b)(d₁-d₂)+2x+ (d₁-d₂)² 4x (c)(d₁+d₂)+ +2x+ (d₁-d₂)² 4x (d)(d-d₂)+2x+ (d₁ +d₂)² 4x 3. In a cone pulley, if the sum of radii of the pulleys on the driving and driven shafts is constant, then (a) open belt drive is recommended (b) cross belt drive is recommended (c) both open belt drive and cross belt drive are recommended (d) the drive is recommended depending upon the torque transmitted Due to slip of the belt, the velocity ratio of the belt drive 4. (a) decreases 5. (b) increases (c) does not change When two pulleys…arrow_forwardQ3: (10 MARKS) A piston with a weight of 29.4 N is supported by a spring and dashpot. A dashpot of damping coefficient c = 275 N.s/m acts in parallel with the spring of stiffness k = 2400 N/m. A fluctuating pressure p = 960 sin 30t N/m² acts on the piston, whose top surface area is 0.05 m². Determine the steady-state displacement as a function of time and the maximum force transmitted to the base. P=Po sin cot Warrow_forward9. 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.arrow_forward
- 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 approxiarrow_forward6. 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.arrow_forward2 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.arrow_forward
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