PNA2

Question 1

Why is an orb fitting preferable to as a tapper thread fitting

Answer 1

It causes less stress and distortion

Question 2

Should you normally instal a cylinder with the ports at the top or the bottom

Why

Answer 2

Top

Allows for bleeding out after installation

Question 3

Why is it important to align a cylinder to the load to which it is attached

Answer 3

To avoid wear on walls and on seals

Question 4

What is the most costly result of leaks in a cylinder

Answer 4

Dirt and air

Question 5

What is the operating principle of any hydraulic motor

Answer 5

Fluid pushes to turn the drive shaft

Question 6

What does a decrease in mechanical in mechanical efficiency indicate

Answer 6

Increase in internal friction

Question 7

What does a decrease in volumetric efficinecy indicate

Answer 7

Internal leakage

Question 8

What type of gear motor requires timing

Answer 8

Orbiting gear

Question 9

What is found in a vane motor that is not in a vane pump

Answer 9

Springs under the vanes

Question 10

How can you change the displacement of a cam type radial piston motor

Answer 10

Change cam ring to a different size

Question 11

By shutting off the cushion valve at the rod end of a cylinder with a load pulling what danger could occurs

Answer 11

Pressure intensification

Question 12

What happends if you dont time a radial piston motor correctly

Answer 12

It runs in revers

Question 13

Do pumps create pressure or flow?

Answer 13

Flow

Question 14

Why are positive displacement pumps used for hydraulics

Answer 14

More acurate flow control

Question 15

Does the volume of the pumping chamber expand or contract at the inlet

Answer 15

Expand at inlet

Question 16

Three methods of changing the output of a pump

Answer 16

Built in flow controls
drive speed change
Variable displacement

Question 17

Wish swash plate control, regulates the flow to suit any given load

Limits the maximum pressure in the system

Answer 17

Load sensing compensator

Pressure limiting compensator

Question 18

When you install a load sensing pump what must the load sensor be set at to bring the bias piston back to full stroke

Answer 18

200-400 psi

Question 19

Does the space between the vanes increase or decrease at the inlet

Answer 19

Increase

Question 20

How is output flow increased on an unbalanced vane pump

Answer 20

By moving the cam further off Center

Question 21

What is the rotation of a factory built vane pump

Answer 21

Right hand

Question 22

On a gear pump do gears go into or come out of mesh at inlet

Answer 22

Come out of mesh

Question 23

Fro what end of the pump is the rotation defined

Answer 23

Drive end

Question 24

How do you change the direction of rotation in a balanced vane pump

Answer 24

Flip over cam ring, rotor and flex plate assembly

Question 25

What pump is more compact balance or Unbalanced vane

Answer 25

Balance vane

Question 26

Pumping chambers increase or decrease in volume at inlet and then increase or decrease as they push out fluid at discharge

Answer 26

Increase volume at inlet, decrease at discharge

Question 27

How is fluid ported in and out of a radial piston pump

Answer 27

Through check valves in the Pistons

Question 28

What's more efficient gear pump or piston pump

Answer 28

Piston pump

Question 29

Does an internal gear pump have the same number of teeth as the outside or should it have fewer

Answer 29

Fewer

Question 30

Why is a very close fit necessary between the teeth the casing on a gear pump.

Answer 30

To prevent bypassing back to inlet

Question 31

Which is the best pump to use if you have to locate it above the surface of the fluid: an in-line axial pump or a bent axis

Answer 31

Bent axis

Question 32

What is the purpose of a bias piston in a in line axis piston pump

Answer 32

To move the swash play to the maximum angle

Question 33

What provides more force to keep the vane in a vane pump against the cam ring

Answer 33

intra-vane Cartage style -= high efficiency, high pressure

Question 34

Positive seals and non positive seals differ how

Answer 34

Positive seals are designed for zero leakage Non positive seals allow controlled leakage

Question 35

How do static and dynamic seals differ

Answer 35

Static is for stationary parts Dynamic Is for moving parts

Question 36

What 2 seal types are used to deal against the case pressure in a hydraulic pump or motor

Answer 36

High pressure lip seals or mechanical seals

Question 37

What seals are used for pressures over 150 psi

Answer 37

Mechanical seals

Question 38

What are 3 accumulator applications

Answer 38

Compensate for lag Emergency power Makeup fluid for leakage

Question 39

Four types of piston motors

Answer 39

Inline axial piston Bent piston Radial piston Cam type radial piston

Question 40

Maximum angle in an inline axial motor has what speed and what torque

Answer 40

Low speed High toque