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Test Review > Hydraulic Trouble shooting, math, fluid seals test > Flashcards

Hydraulic Trouble shooting, math, fluid seals test Flashcards

1
Q

when troubleshooting a hydraulic system on site you would

use a schematic of the system

ask a journeyman for help

talk with the operator

all the above

A

All of the above

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2
Q

when troubleshooting a hydraulic system on site you would

use a schematic of the system

ask a journeyman for help

talk with the operator

all the above

A

all of the above

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3
Q

if a hydraulic pump has lost some of its efficiency you would know this by

slow moving actuators

loss of pressure

excessive oil flowing thru the pump’s drain line when tested

both the first and 3rd answers

A

Both the first and third answers are correct

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4
Q

Areation is caused by?
-entrained air bubbles in the oil
- Leaking pump seals
- to much oil in the tank
- all of the above

A

leaking pump seals

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5
Q

Cavitation which is distinguished by a rattling noise is checked by?
- Looking for a clogged inlet
- Installing a vaccum gauge on the pressure line
- installing a flow meter on the drain line
- All of the above

A

looking for a clogged inlet

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6
Q

Misaligned couplings lead to?
- loose mounting bolts
- broken drive shafts
- vibration
- all of the above

A

all of the above

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7
Q

an axial piston pump with a variable displacement could have ______ if the flow or pressure was low?
- The pressure or load sensor out of adjustment
- A blockage in the pilot port to load sensor or compensator
- all of the above

A

all of the above

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8
Q

low output speed of an actuator could be caused by?
- A volume control valve
- A pressure reducing valve
-A directional control valve
-All of the above

A

A volume control valve

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9
Q

an AC solenoid can burn out and can be noisy (hum)

true

false

A

true

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10
Q

To test a directional control valve for proper actuation, you could

push the armature pin or manual override to see if the actuator moves

see if the hoses jump when the valve is energized

see if the light comes on at the end of the directional control valve when it is energized

all the above

A

all of the above

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11
Q

a compound (pilot operated) relief valve has ___________then a direct acting

a higher override

less stages

lower pressure override

all the above

A

lower pressure override

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12
Q

a most likely problem with a relief valve is a broken spring

true

false

A

True

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13
Q

a pressure reducing valve is a normally closed valve. (senses pressure up stream of the valve

true

false

A

False

down stream of the valve

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14
Q

a sequence valve has an external drain line to the tank

true

false

A

True

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15
Q

a counterbalance valve that will not let the load lower has what type of problem

broken spring

worn valve

incorrect adjustment (set to low)

incorrect adjustment (set to high)

A

Incorrect adjustment (set to high)

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16
Q

after installing a flow control, the speed of the actuator is slow in the wrong direction. the problem is

dirt on the valve seat

incorrect adjustment

worn throttle spool

valve installed backwards

A

Valve is installed backwards

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17
Q

to test a cylinder for leaks, pressurize either end and see if any oil comes out the other end.

true

false

A

True

if oil comes out it means oils is flowing past the piston

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18
Q

if a cylinder has jerky movement or is squealing, the most likely cause would be aeration

true

false

A

True

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19
Q

hydraulic motors that are not producing full torque (pressure) have what kind of problem

internal leakage

shaft seal leaks

relief valve set to low

all the above

A

Relief valve set to low

other answers are flow issues not pressure

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20
Q

when troubleshooting hydraulic systems, the things to look for to solve the issues are

pressure

speed

heat

all the above

A

all of the above

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21
Q

to help troubleshoot a system you need to know how the system works

true

false

A

True

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22
Q

a tachometer will help you troubleshoot what type of issues

flow

speed

pressure

both the 1st and 2nd answer

A

flow and speed

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23
Q

pressure gauges are protected from damage (from pressure spikes) by the use of snubbers

true

false

A

True

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23
Q

if you were checking if there was any flow going over the relief valve, you would use a

flow meter on the outlet side of the relief valve

temperature gauge on the pump

flow control at the actuator inlet

none of the above

A

Flow meter on the outlet side of the valve

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24
Q

particle counters count particles at 3 different micron ratings. they are

2, 5, 10

2, 10, 20

4, 6, 14 or 2, 5, 15

2, 4, 14

A

4,6,14 or 2,5,15

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25
Q

when troubleshooting electro-hydraulics with a servo valve, you would know it would

be an open loop system

be a closed loop system

be controlled by air

not have feedback

A

Be a closed loop system

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26
Q

servo valves have amplifier cards that convert an electronic signal from the feedback device to the servo valve____________________

torque motor

encoder

transducer

tachometer

A

Torque motor

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27
Q

when troubleshooting a system with many branches or circuits within the system, you would use a schematic with a solenoid chart to help resolve the issue(s)

true

false

A

True

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28
Q

a common fault with servo valve systems that make them inoperable is a plugged filter.

true

false

A

True

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29
Q

a starting point to solve hydraulic issues when a system is not working properly is to talk to the operator running the system

true

false

A

True

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30
Q

what is the force(lbs) if 500 psi is applied to the low pressure side of an intensifier cylinder? the area on the input side is 10 sq in and the output piston is 1 sq in

500

100

2500

5000

A

5000

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31
Q

what is the load the porta-power system will lift. m.a. of handle=15/1, piston d=0.5”, ram D=3”, E=50 lbs

27,000 lbs

12,000 lbs

17500 lbs

22500 lbs

A

27000 lbs

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32
Q

calculate the HP required to drive a pump in a hydraulic cylinder hydraulic system with the following specifications. ram piston diameter=3”, piston rod diameter=1.5”, return stroke force= 6000lbs, return stroke speed= 350 in/min

7.4

6.2

4.8

5.3

A

5.3

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33
Q

a hydraulic hoist must not lift any vehicles over 5000 lb. the piston diameter=10”. what is the relief valve set at.

59.2 psi

63.7 psi

45.9 psi

77.7 psi

A

63.7

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34
Q

you have a system with a 35 hp motor and a 20 gpm pump. the cylinder diameter=3”, hydraulic tubing tensile strength is 55,000 psi, the steel tubing has a 3/4” outside diameter with a wall thickness of 0.109”. what is the maximum line pressure if it has a safety factor of 6.

2777

2664

5854

2864

A

2664

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35
Q

use the following information to calculate the effort needed. d=0.554”, D=3.25”, L= 3050 lbs, LD = 0.255”

74.4 lbs

66.6 lbs

88.6 lbs

59.2 lbs

A

88.6

36
Q

what amount of torque is being produced if the system has a 25 gpm pump turned by a 1200 rpm electric motor and a hydraulic motor creating a pressure of 1770

113 ftlbs

75 ftlbs

243 ftlbs

413 ftlbs

A

113 ft/lbs

37
Q

what diameter of cylinder will be needed to lift 5500 lbs with a pressure of 1000 psi

2.5”

2.75”

3”

3.25”

A

2.75

38
Q

when troubleshooting a hydraulic system, you find a slow actuator acting against the full force in the system. the problem would not be

the pump wearing out

damaged seals in the actuator

flow control restricting to much

system relief valve set above pump operating pressure

A

system relief valve set above pump operating pressure

39
Q

when troubleshooting a hydraulic system, you find to low of a pressure. it could be

pressure reducing valve set to low

pressure relief valve set to high

pressure relief valve set to low

both the first and 3rd answers are correct

A

Both first and third asnwers

40
Q

if you have erratic movement in your actuators it is a sign of

erratic pressure

air in the fluid

no lubrication on machine ways or linkage

all the above

A

all of the above

41
Q

if you had a hydraulic system that ws overheating and had excessive noise at the pump, the problem would likely be

fluid viscosity to high

excessive pump speed and load

dirty inlet filter

all the above

A

all of the above

42
Q

if you found a hydraulic motor with a broken shaft, the problem could be caused by

system pressure overload

misalignment

failed bearing

all the above

A

all of the above

43
Q

excessive heat in a hydraulic system could be caused by

proper fluid viscosity and proper oil

oil bypassing a filter

relief valve stuck partly open

both the 2nd and 3rd answers are correct

A

Both second and third answers are correct

44
Q

o low of a flow rate and to low of system pressure could be caused by the relief valve setting being to low

true

false

A

True

45
Q

excessive pressure in a hydraulic system would be caused by a pressure relief valve with a broken spring

true

false

A

False

46
Q

valve issues found when troubleshooting can be any of the following. spool sticking, defective O-rings and a burnt out solenoid

true

false

A

True

47
Q

invisible leaks on cylinders are between the piston and the cylinder wall and between the rod and cylinder wall

true

false

A

True

48
Q

erratic pressure could be caused by a defective accumulator or one that has lost its charge of nitrogen into the fluid

true

false

A

true

49
Q

the MAIN function of hydraulic fluid is to

transmit power from the pump to the actuator

lubricate moving parts

seal clearances

carry heat and contaminates away

A

Transmit power from the pump to the actuator

50
Q

petroleum based hydraulic fluids are used most frequently because

low cost

readily available

good lubricating qualities

all the above

A

all of the above

51
Q

water based fluids that are glycol - based should have the pump mounted below the fluid level because the weight of it is heavier than water

true

false

A

true

52
Q

synthetic oils are being used more and more because they have

a high resistance to oxidation

a high viscosity index

longer life

all the above

A

all of the above

53
Q

vegetable oils such as soy oil are used when there are environmental considerations to take into account

true

false

A

true

54
Q

store hydraulic fluids so the fluid is protected from the elements and the environment is protected form the fluid

true

false

A

true

55
Q

the baffle in a hydraulic tank

keeps oils separated

keeps the water from getting into the oil

allows the mixing of the additives

slows the fluid down

A

Allows fluid to slow down

56
Q

the inlet filter should be about _____________ and have a _____________ for safety

100 microns, bypass

3 microns, bypass

100 microns, check valve

A

100 microns and bypass

57
Q

the return line outlet should be ______________ the fluid level and the angle of the cut (of the pipe) should be___________ the path to the pump inlet

above, facing

below, facing away from

above, facing away from

below, facing

A

Below facing away from

58
Q

to help save the environment from major spills, you can use level indicators and automatic shut-offs to control the amount of oil lost

true

false

A

True

59
Q

water coolers are more efficeint than air coolers as they can control the temperature mor accurately

true

false

A

True

60
Q

the breather cap on top of the reservoir allows atmoshperic pressure in to push on the oil when the pump is creating a vacuum

true

false

A

True

61
Q

reservoirs that are vented use ___________________ to help push the oil into the pump

supplied air pressure

atmospheric pressure

no air pressure

all the above

A

Atmospeheric pressure

62
Q

if you have a closed circuit reservoir, you would use about ______________ psi

10-15

5-10

1-3

25-50

A

1-3

63
Q

a hdyraulic tank that has the pump mounted inside the tank is the

flat top

L-shaped

overhead stack

vertical mount

A

Vertical mount

64
Q

about 80 % of hydraulic component failures are due to____________

contamination

lack of lubrication

leaky seals

industrial mechanic errors

A

Contamination

65
Q

filter carts can

transfer oil to the reservoir

clean the oil

empty the reservoir

all the above

A

All of the above

66
Q

the type of contamination that gets into the system from the outside is

built-in

ingressed

generated

wear related

A

Ingressed

67
Q

a micron is equal to 1 millionth of a meter

true

false

A

true

68
Q

when setting IOS cleanliness targets for a hydraulic system, you know they are being attained by

proper filter systems

using a portable partical counter

visually inspecting them

oil changes at frequent intervals

A

Using a portable particle counter

69
Q

it is necessary to have a bypass valve on a filter to

protect the filter element from collapse

protect the system from not getting the proper amount of oil

protecting the pump from cavitation

all the above

A

All of the above

70
Q

the pleated fiberglass filter is supported by

a diffuser layer

filter media

metallic mesh

none of the above

A

Metallic mesh

71
Q

depth type media consists of __________________ that capture dirt

matrix of fibres

clay

charcoal

fullers earth

A

Matrix of fibers

72
Q

all hydrauic systems should have a filter located in the

pressure line

return line

pressure line before the DCV

after the cylinder

A

Return line

73
Q

beta ratio is the

efficiencey of the hydraulic system

efficiency of the pump

efficiency of the filter

volumetric efficiency of the pump

A

Efficiency of the filter

74
Q

to select the proper filter for your system, you would use a filter placement chart or manufactures recommendation.

true

false

A

True

75
Q

maintenance of hydraulic fluid would include

water contamination protection

heat protection

oxidation protection

all the above

A

all of the above

76
Q

dynamic O-rings have the same amount of squeeze as the static O-rings

true

false

A

False

77
Q

for every 10 degrees C above 60 degrees C, the oxidation rate

tripples

doubles

quadruples

none of the above

A

Doubles

78
Q

O-rings in hydraulic systems can be used as dynamic seals

true

false

A

True

79
Q

never add sealant to the first 2 threads (from the end of the pipe) as it could add contamination into the system

true

false

A

True

80
Q

to help tighten a loose fitting high pressure lip seal, you could add loctite to the inside of the housing where the seal sits

true

false

A

True

81
Q

always use emery cloth in a perpendicular motion (not spiral motion) around the shaft to help stop spiral leaks

true

false

A

True

82
Q

an accumulators MAIN function is to

absorb shock

even out pulsations

protect against over-pressure

store pressurized fluid

A

Store pressurized fluid

83
Q

you should NOT use a flared fitting in a _______________ environment

dirty

hot

slippery

high vibration

A

High Vibration

84
Q

flareless fitting are used with

thin walled tubing

thick walled tubing

both the 1st and 2nd answer

noe of the above

A

Thick walled tubing

85
Q

when tightening flared fittings (after tightening hand tight) use a flare (tube) wrench and tighten 1/4 turn for fittings under 5/8” and 1/8 of a turn for sizes over 5/8”

true

false

A

True

86
Q

when troubleshooting a pump cavitation issue at the inlet, the pressures you will be looking at will include both vacuum and atmospheric pressures

true

false

A

True

87
Q

when installing hydraulic hoses, make sure to ______________ to make sure they are installed properly

have a slight twist in the hose

no twist in the hose

the hose is stretched slightly

the hose has the fredom to whip around

A

No twist in the hose

88
Q

if you see blisters in the outer rubber layer of a hose this tells you that

the oil has been over-heated

there is oil leaking thru the reinforcement

the iner-tube is comming thru the reinforcement

it is normal to have some blisters

A

There is oil leaking through the reinforcment

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