MET230: Hydraulics and Pneumatics - Unit 2 Review Assignment 1

MET230: Hydraulics and Pneumatics
Unit 2 Review Assignment 1
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Question 1
Which of the following statements is true about limited rotation hydraulic motors?
A. They are also called non-oscillating motors
B. They can’t rotate in the counter clockwise direction
C. They are classified as linear actuators
D. They rotate through less than one complete cycle
E. None of the above
Question 2
Which of the following statements lists the main advantages of gear motors?
A. Long expected life and zero maintenance
B. Highest volumetric and mechanical efficiencies
C. Simple design and subsequent low cost
D. High speed and high torque
E. None of the above
Question 3
Which of the following statements define the volumetric efficiency of a hydraulic
motor?
A. Volumetric efficiency is the theoretical flow rate the motor should consume,
divided by the actual flow rate consumed by the motor.
B. Volumetric efficiency is the actual torque delivered by the motor, divided by
the torque the motor should theoretically deliver.
C. Volumetric efficiency is the actual power delivered by the motor, divided by
the actual power delivered to the motor.
D. There is no such thing as volumetric efficiency for a motor. This concept
applies to pumps only
E. None of the above
Question 4
Which of the following is NOT true about hydraulic motors?
A. A motor uses more flow than it theoretically should
B. A hydraulic motor delivers less torque than it theoretically should
C. Hydraulic motors extract energy from a fluid and convert it to mechanical
energy
D. In vane motors, vanes are held in contact with the cam ring by springs or by
being pressure-loaded
E. None of the above
Question 5
Which of the following is NOT true about hydraulic valves?
A. Directional control valves determine the path of a fluid in a given circuit
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B. Pilot check valves can permit flow in the normally blocked opposite direction
C. A pressure relief valve is used to limits the maximum pressure in a hydraulic
system
D. Pressure reducing valve is another name for pressure relief valve
E. All of the above
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Problem 1
A rotary actuator has the following physical data:
Outer radius of rotor = 0.75 in
Outer radius of vane = 1.5 in
Width of vane = 0.75 in
If the torque load is 1000 in∙lb, what pressure must be developed to overcome the
load?
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Problem 2
A hydraulic motor has 5.5-in3 volumetric displacement. If it has a pressure rating of
1500 psi and receives oil from a 12.5-gpm theoretical flow-rate pump, find the
motor
a. Speed
b. Theoretical torque
c. Theoretical horsepower
Solution
Speed
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Theoretical torque
Theoretical horsepower
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