Hydrostatic Drives

Question 1

What is a hydrostatic drive?

Answer 1

a fluid drive system that uses oil pressure hydraulic power to the make mechanical power.

Question 2

What two principles of hydraulics are involved in a hydrostatic drive?

Answer 2

1. Liquids have no shape of there own
2. Liquids will not compress

Question 3

What are the basic functional parts of a hydrostatic drive?

Answer 3

-pump
- Motor

Question 4

What controls the volume and pressure of the oil?

Answer 4

Swashplate

Question 5

What is a fixed displacement hydraulic pump or motor?

Answer 5

Displacement cannot be
changed

Question 6

What is a variable displacement hydraulic pump or motor?

Answer 6

Displacement can be changed
by the use of the swashplate

Question 7

Does the swashplate rotate?

Answer 7

No

Question 8

Is there an advantage to a variable displacement pumps or motors?

Answer 8

pressure, flow, temperature.

Question 9

What additional components are required to complete a hydrostatic drive?

Answer 9

Cooler
Pump
motor
Charge pumps
control valve
Filters
Reservoirs

Question 10

In a hydrostatic motor, what is the position of the swashplate on in neutral?

Answer 10

Vertical

Question 11

Why is there no high pressure oil in the motor in neutral?

Answer 11

No Oil needed

Question 12

What is the position of the swashplate on the pump in forward?

Answer 12

Angled in open direction

Question 13

Are the pistons of the pump against the swashplate?

Answer 13

Yes

Question 14

What is the position of the swashplate on the pump in reverse?

Answer 14

Angled in opposite direction of forward

Question 15

Does the pump reverse for reverse operation?

Answer 15

No

Question 16

Can more than one hydrostatic drive unit be used on the same machine?

Answer 16

Yes

Question 17

What are at least four advantages of hydrostatic drives?

Answer 17

1 Convenience
2 Single lever control for stepless
3 clutch-less
4 on the go changes of speed and 5 direction,
6 infinite variability
7 flexible location
8 Shift on the fly

Question 18

If a machine equipped with a hydrostatic drive will not move, what are two possible causes?

Answer 18

1. System low oil
2. Faulty control linkage

Question 19

If a hydrostatic drive system is noisy, what is the most likely cause?

Answer 19

Air in the System

Question 20

A hydrostatic drive uses fluids at high pressures and relatively
low _____________

Answer 20

speeds

Question 21

One of the principles of hydrostatics is that liquids will not _____________

Answer 21

compress

Question 22

________________ is the quantity of oil a pump can move in one revolution.

Answer 22

Displacement

Question 23

A fixed displacement motor does not have a ________________

Answer 23

moveable swashplate

Question 24

If a given amount of oil out of a pump causes a motor to turn at a given speed, more oil will __________________

Answer 24

Speed up the motor

Question 25

In a hydrostatic drive, the charge pump supplies ___________ to ___________

Answer 25

Make-up oil to the hydrostatic pump

Question 26

Some of the possible pump and motor combinations are:

Answer 26

a) Fixed displacement pump and variable displacement motor.
b) Variable displacement pump and variable displacement motor.
c) Variable displacement pump and fixed displacement motor.