Hydraulics

Question 0

Annular area is?

Answer 0

Base area - rod area

Question 1

Hydrodynamics are high flow low pressure systems hydrostatic is

Answer 1

High pressure low flow

Question 2

Double the diameter = 4 times______?

Answer 2

The power and 4 times slower

Question 3

Psi A is?

Psi G is?

Answer 3

Psi a is absolute and

Psi g is calibrated to atmospheric pressure (gauge starts at 0)

Question 4

1 bar = _____ psi

1Atm = _____ psi = _____ bar

Answer 4

14. 50 psi

14. 7 psi = 1.01 bar = 1 Atm

Question 5

The resistance to flow creates

Answer 5

Pressure

Question 6

An example of a pressure loss is

Answer 6

Long lines
Restrictions
Improper fittings

Question 7

A force related complaint would be a ?

Answer 7

Pressure problem

Question 8

A complaint of speed of unit would be a ?

Answer 8

Flow problem

Question 9

An example of a non positive displacement pump is

Answer 9

Water pump ( rotors don’t contact walls just turn fluid)

Question 10

The max low efficiency of a pump is

Answer 10

80%

Question 11

What is the ideal efficiency?

Answer 11

Ideal would be 95% Mechanical efficency of 5% automatically withdrawn

Question 12

The inlet is bigger on a pump to?

Answer 12

Never starve the pump and

Prevent cavatation

Question 13

The measure meant of a micron is?

Answer 13

One millionth of a meter

Question 14

Characteristics of hydraulic oil are

Answer 14

Prevents rust, the formation of sludge, varnish and gum, corrosion and pitting Retain stability, maintain viscosity for a wide temp range

Question 15

When viscosity is to high it causes

Answer 15

Increased power to drive system increased temps, greater pressure drops , sluggish operation and greater retention of air

Question 16

When viscosity is too low

Answer 16

Increased internal leakage ( causeing greater heat)
Actuator output speed decreased due to increase internal leakage
Excessive wear reduced oil strength

Question 17

Oil viscosity is measured in 3 ways

Answer 17

Absolute viscosity
Kinematic viscosity
Relative viscosity

Question 18

Absolute viscosity measures?

Answer 18

The force per unit area requires to move two surfaces with a film of oil
(Centipoise cP)

Question 19

Kinematic viscosity measures?

Answer 19

Amount of time required for a given volume to flow through a capillary tube. (Centistoke cSt)

Question 20

Relative viscosity measures ?

Answer 20

Measures amount of time for a given quantity of oil to flow through a standard orfice while being held at specific temp ( saybolt universal seconds SUS)

Question 21

ISO stands for

Answer 21

International standards organization

Question 22

SAE stands for

Answer 22

Society of automotive engineers

Question 23

The rate of oxidation in hyd oil depends on

Answer 23

Amount of air the oil is exposed to
The temp of oil(dramatic effect)
The chemical makeup of oil

Question 24

The baffle plate in the hyd reservoir function is

Answer 24

Allow room for air to escape and contaminants to be contained in return side Also avoids turbulence and allows oil to be cooled and re circulate

Question 25

80% of hydraulic failures are caused by ?

Answer 25

Poor hydraulic oil conditioning

Question 26

Three types of contamination are

Answer 26

• Built in (machine assembly, handling and containing) -ingressed (introduced when servicing)
• internally (particles removed from internal surface)

Question 27

Efficency is measured by

Answer 27

After filter ➗ Before filter

–<—

Question 28

Filter permeability is

Answer 28

The ease at wich fluid passes through the media

Question 29

NPTF are _______________

Answer 29

One time tightening

Question 30

OD- wall thickness2 =

Answer 30

ID inner diameter for black steel

Question 31

The higher the schedule of pipe the?

Answer 31

Thicker the wall

Question 32

Pump flow rate calculation for SAE is?

Answer 32

Pump displacement x RPM
___________________________
231in gal

Question 33

Pump flow rate calculation for metric is

Answer 33

Pump displacement x RPM
_________________________
1000