hydraulics tears

Question 1

Pressure in a hydraulic system at all times is approximately equal to:

1) The minimum resistance to flow.
2) The pressure rating of the pump.
3)The relief valve pressure setting.
Incorrect Response
4) The maximum resistance to fluid flow.

Answer 1

1. The min resistance to flow

Question 2

power output formula with pump efficiency?

Answer 2

output power (kW)= Flow Rate (L/min) x Pressure (MPa) x 0.0167 / efficiency

Question 3

Bernoulli’s principle basically states that as the speed of a fluid decreases its pressure would:

1) Decrease
2) Increase
3) Become kinetic
4) Stay the same

Answer 3

2. Increase

Question 4

A momentary rise in pressure is called:

1) Pilot pressure
2) Burst pressure
3) Surge pressure
4) Charge pressure

Answer 4

3. surge pressure

Question 5

The pressure compensator on the pump of a closed center system is the same as what to a open center system?

Unloader valve
Flow Control Valve
Reducing Valve
Relief Valve

Answer 5

Relief valve

Question 6

Pressure plates in gear pumps:

1) Seal the sides of the gears against leakage
2) Support the gears against pressure
3) Are all bronze
4)Support the pump shafts

Answer 6

1. seal the sides of the gears against leakage

Question 7

External gear pumps have 2 external gears that grab the oil from the smaller inlet port and move the oil through the middle of the pump to the larger outlet ports.
True

False

Answer 7

False

Question 8

What would an uncentered servo piston cause on a servo controlled variable displacement reversible pump?

1) It would cause the motor to drift
2) It would cause the machine to drift to one side when travelling
3) It would have no effect
4) Both 1 and 2

Answer 8

Both 1 and 2

Question 9

Leakage oil in gear pumps is routed to the pump inlet

1) So the bushings do not burn up
2) So the gears are not side loaded
3) To protect the shaft seal
4)All the above

Answer 9

3. to protect the shaft seal

Question 10

Increasing the displacement of the motor will increase the torque output but reduce the motor speed

True
False

Answer 10

True

Question 11

Mechanical face seals are classified as:

1) Static
2) Rotary
3) Dynamic
4) Both A and C

Answer 11

3. dynamic

Question 12

Select the incorrect statement regarding vane type hydraulic motors

1)Vane motors are commonly bi-directional and reversible
2)Bi-directional vane motors require external drain ports
3)Vane motors have a minimum rotating RPM to ensure the vanes make contact with the cam ring
4)Balanced vane motors have 4 sets of transfer slots and have an elliptical cam ring

Answer 12

3. vane motors have a minimum rotating RPM to ensure the vanes make contact with the cam ring

Question 13

Select the correct swashplate position for a 2 speed pressure compensated axial piston motor with the key on and engine off in a machine.

Maximum swashplate position

Minimum swashplate position

Answer 13

minimum swashplate angle

Question 14

What is the purpose of the piston relief valves mounted commonly on the end of dozer lift cylinders.

1)To limit the maximum pressure in the cylinder
2)To allow for greater cooling
3)To allow for quicker dropping of the blade
4)To allow for a quicker cycle time

Answer 14

2. to allow for greater cooling