Jasons Review Flashcards

1
Q

What best describes a three-way/two position valve?

A

It can be used when air needs to be released when valve is closed

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2
Q

Bleed Off Flow Control is _____________ energy efficient than meter-in or meter-out flow control.

A

More

Bleed Off Flow Control is most efficient

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3
Q

What does an open top indicate with an oil reservoir symbol?

A

It is vented to atmosphere

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4
Q

True or False;
Pilot-To-Open check valves are Normally Closed?

A

True

“lock valves”

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5
Q

With hydraulic systems, pump inlets should be ___________ than the discharge lines.

A

Larger Diameter

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6
Q

A pressurized hydraulic reservoir can be used to solve which problem?

A

Cavitation

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7
Q

What best describes a counterbalance valve?

A

They are used to prevent a load suspended by a cylinder from free fall.

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8
Q

What best describes a check valve?

A

They are used to prevent reversal of fluid flow

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9
Q

What is an example of a positive seal?

A

Connector fittings on pipe tubes and housing

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10
Q

What is a cause of aeration?

A

Leaking pump inlet fittings
Low hydraulic fluid levels
Turbulence in the tank

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11
Q

When does cavitation occur?

A

When fluid moves from a low pressure area to a high pressure area.

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12
Q

If hydraulic pipe is changed out and replaced with a pipe that has a smaller inside diameter, the speed of the fluid will?

A

Increase

Bernoullis Principle - speed up, pressure down

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13
Q

What will not control the output of a hydraulic pump?

A

Increase relief valve setting

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14
Q

How can you control the output of a hydraulic pump?

A

Use a variable displacement pump
change the speed of the driver
use a pressure compensation pump

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15
Q

What does a diagonal arrow on a hydraulic symbol always indicate?

A

its variable in its output

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16
Q

What does the term pressure override refer to with a pressure relief valve?

A

The difference between cracking pressure(first drop through), and full flow pressure to fully open the valve.

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17
Q

What occurs in an inline axial piston motor when the swash plate is at maximum angle?

A

Low Speed, High Torque

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18
Q

A hydraulic sequence valve must be installed so that the inlet of the valve is connected to the _________ cylinder and the outlet to the _________ cylinder.

A

First
Second

Sequence Valve has drain*

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19
Q

The advantage of using a proportional directional control valve is that they can also:

A

Control Flow
notes
-solenoid controlled
-infinitely variable
horizontal lines above and below dcv indicate proportional dcv.

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20
Q

With a proportional dcv the spool movement is proportional to?

A

the electrical input from amplifier card

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21
Q

What best describes an unloading valve?

A

They are used to depressurize part of a system and often used to circulate fluid at low pressure.

-saves energy

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22
Q

With accumulators used for energy storage applications, pre-charge to ______% of minimum system pressure.

A

90% for energy storage
75% for shock
70% for pulsations

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23
Q

What does a filter with a beta ratio of 15 indicate?

A

it allows 1 particle to escape for every 15 that enter the filter.

15:1

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24
Q

What should be checked if a hydraulic cylinder has hot spots?

A

Leaking piston seals

-also be loss of speed.

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25
Q

What best describes a pressure reducing valve?

A

They are normally open valves that are actuated by pressure in a branch of the circuit in which they are installed

-pilot at outlet
-normally open
-drain

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26
Q

Flow is produced by a ________ across an oriface.

A

Pressure drop

flow - goes high pressure to low pressure

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27
Q

What is the definition of Power?

A

The rate at which work is done

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28
Q

How is efficiency % found?

A

Output over input times 100

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29
Q

In a hydrostatic(closed loop) system, what returns the case drain oil to the main pump?

A

Charge pump

-charges inlet so you don’t get cavitation

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30
Q

In a solenoid controlled, pilot operated DCV the main stage actuation method is?

A

Hydraulic pressure

-piggy back valve, electric over hydraulic

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31
Q

What pumps cannot be variable in volume?

A

External gear pump

*all gear pumps are fixed.

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32
Q

A bypass compensator flow control valve can only be used in what location?

A

Meter-In

33
Q

What harms to a hydraulic system does gum and varnish create?

A

Sticky Valves

34
Q

What is a major advantage of a vertical mount pump and reservoir system?

A

Being inside the reservoir maintains stability and cleanliness of the pump.

35
Q

True or False;
A balanced vane pump has much more compact design than an unbalanced vane pump.

A

True

36
Q

True or False;
Oil from an air compressor in a pneumatic system aids in system lubrication.

A

False

37
Q

When using a load sensing pump, the system pressure will never rise above;

A

Compensator setting

Load Sensing - Load + Setting when moving
max pressure determined by pressure compensator.

38
Q

What piping material is suitable for pneumatic systems but not hydraulic?

A

Copper

*never use Teflon, Copper, Galvanized for hydraulics.

39
Q

The resetting of a maximum pressure relief valve too high may cause?

A

Broken components

40
Q

What is used to prevent a runaway situation on a hydraulic motor?

A

The external sensing pilot line on a brake valve.

Brake Valve:
Internal and External pilot lines
External - prevent runaway loads
Internal - Dynamic Braking (like abs in car)

41
Q

Actuator speed can be decreased by?

A

Decreasing Flow

42
Q

Servo valves require?

A

Pressure line filter with no bypass.

43
Q

What is the diameter of a hydraulic hose with the marking of DASH 8?

A

1/2”

8/16 = 1/2

44
Q

Which of the following is a directional control valve?

  • Pressure Relief Valve
    -Check Valve
    -Needle Valve
    -Sequence Valve
A

Check Valve

45
Q

Which Valves require an external drain?

A

Pressure Reducing Valve
Sequence Valve

46
Q

What valve only allows flow in one direction?

A

One-way valve

-check valve

47
Q

What type of valves use a spring loaded ball?

A

Directional Valve

-check valve

48
Q

What valve is piloted at its outlet and limits pressure downstream?

A

Pressure Reducing Valve

49
Q

What is the optimal crush on hydraulic o-rings?

A

10%

50
Q

How do you change the output of an adjustable vane pump?

A

Adjust the cam ring

-eccentric cam ring

51
Q

What limits system pressure in a hydraulic system when using a fixed displacement pump?

A

Maximum Pressure Relief Valve

52
Q

What valve allows a pump to operate at low pressure?

A

Unloading Valve

53
Q

Hydraulic symbol:
cylinder with ram
cushion on cap end
diagonal arrow through cap end of cylinder

A

Cushion cylinder in cap end when retraction.

adjustable because of the arrow?
Question 56 on Jason review test.

54
Q

The NUMBER 1 cause of wear in pumps is?

A

Contaminants

55
Q

The angle of a hydraulic JIC fitting is?

A

37 degrees

56
Q

Leaking pumps cause;

A

Heat increase and speed reduction

57
Q

Pilot to Open check valves are used to;

A

Lock cylinders

58
Q

Throttle valves control;

A

Speed

59
Q

A brown sticky substance on a hydraulic valve is;

A

Gum and Varnish

60
Q

The instrument most commonly used to establish a straight reference line of sight is a;

A

Alignment telescope

61
Q

The procedure for checking the plumb accuracy of a jig transit or theodolite can be accomplished by using a;

A

Heavy plumb bob hanging on a wire in a bucket of oil

62
Q

Horizontal wire alignment, when done correctly, can provide an accuracy as close as;

A

0.0001”

Jasons headphone battery dude

63
Q

When performing an alignment with a laser unit, sudden temperature changes will…..

A

Reduce the accuracy of the unit

64
Q

When referring to alignment procedures, the term plumb refers to a reference aligned to the _______ plane

A

to the vertical plane.

65
Q

The lens of a magnifying glass is a

A

convex lens

66
Q

A pentaprism is the basis of what tool?

A

Optical Square

-accessory for the alignment telescope

67
Q

What laser alignment system requires two cables to operate?

A

Dual Beam/Dual detectors

-no dynamic interruption

68
Q

First step in performing a machine alignment with lasers?

A

Rough alignment with straight edge

69
Q

The term square refers to a reference aligned;

A

90 degrees to the reference line

70
Q

Optical instrument to measure angles in 2 planes.

A

Theodolite

71
Q

A laser alignment unit that is ________ safe can be used in an area that may have explosive gas present.

A

Intrinsically

72
Q

What accessory is required to perform bucking in?

A

Precision lateral adjuster

73
Q

Optical Plumbs are used to:

A

Set up instrument over a spot on the ground

74
Q

What type of pneumatic valve produces an output only when it has two equal pressured inputs?

A

Dual Pressure Valve - “AND”

75
Q

The rpms of a pneumatic tool are determined by;

A

Flow rate

rpm=speed
torque=pressure

76
Q

What pneumatic piping system is subject to air starvation downstream when the upstream demand is heavy?

A

GRID

loop system is best

77
Q

Quick Exhaust valves are used to;

A

Decrease cycle time of a cylinder
AKA
MOVE FASTER

78
Q

An air regulator is normally ______ and piloted at its _______

A

Normally Open and piloted at its outlet.