chapter 30-60_part 1

Question 1

popular in industries.
Hydraulic motors can be applied directly to work. They
provide excellent control for acceleration, operating speed,
deceleration, smooth reversals and positioning.

Answer 1

Hydraulic motors

Question 2

There are two types of hydraulic motors:

Answer 2

(a) High-speed low-torque motors
(b) low–speed high-torque motors.

Question 3

shaft is driven directly from either the
barrel or the cam plate,

Answer 3

high-speed low-torque motors

Question 4

shaft is driven through a
differential gear arrangement that reduces the speed and increases the
torque.

Answer 4

low-speed high-torque motors

Question 5

classification of hydraulic motors

Answer 5

1.Gear motors.
2. Vane motors.
3. Piston motors

Question 6

A gear motor develops torque due to hydraulic pressure
acting against the area of one tooth

Answer 6

Gear Motors

Question 7

According to the piston of the cylinder block and the drive shaft, piston motors are classified as follows

Answer 7

Axial piston motors.
* Radial piston motors.

Question 8

According to the basis of displacement, piston motors
are classified as follows:

Answer 8

• Fixed-displacement piston motors.
• Variable-displacement piston motors

Question 9

depends upon
many factors such as precision of their parts, tolerances between
the mating parts, etc.

Answer 9

Performance of Hydraulic Motors

Question 10

the turning force the
motor exerts from a dead stop.

Answer 10

Starting torque

Question 11

is the exerted when the motor is
running and changes whenever there is a change in fluid
pressure.

Answer 11

Running torque

Question 12

torque necessary to stop
the motor.

Answer 12

Stalling torque

Question 13

is the ratio of
theoretical flow rate to actual flow rate required
to achieve a particular speed

Answer 13

volumetric efficiency

Question 14

what is the formula for volumetric efficiency

Answer 14

the ratio of
theoretical flow rate to actual flow rate

Question 15

is the ratio of actual
work done to the theoretical work done per
revolution.

Answer 15

Mechanical efficiency

Question 16

is the ratio of output power to input power of the motor. Output power is mechanical power output at the shaft and input power is fluid energy supplied to the inlet of the hydraulic

Answer 16

Overall efficiency

Question 17

Classification of pump based on displacement:

Answer 17

• Non-positive displacement pumps (hydrodynamic pumps).
• Positive displacement pumps (hydrostatic pumps).

Question 18

Classification of pump based on delivery:

Answer 18

• Constant delivery pumps.
• Variable delivery pumps.

Question 19

Classification of pump based on motion:

Answer 19

• Rotary pump.
• Reciprocating pump.

Question 20

are primarily velocity-type
units that have a great deal of clearance between rotating and
stationary parts.

Answer 20

Non-positive displacement

Question 21

high slip that
increases as the back pressure increases, so that the outlet may be
completely closed without damage to the pump or system.

Answer 21

Non-displacement pumps

Question 22

not develop a high pressure but move a large
volume of fluid at low pressures

Answer 22

Non-positive pumps

Question 23

have very little
slips, are self-priming and pump against very high pressures, but
their volumetric capacity is low.

Answer 23

Positive Displacement Pumps

Question 24

always deliver the same quantity of
fluid in a given time at the operating speed and temperature. These
pumps are generally used with relatively simple machines, such as
saws or drill presses or where a group of machines is operated with no
specific relationship among their relative speeds.

Answer 24

Constant Delivery Pumps

Question 25

The output of this pump may be varied either manually or automatically with no change in the input speed to the pump.

Answer 25

Variable Delivery Pumps