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## What is the effect of increasing a hydraulic motor displacement on speed and torque?

Increasing the swashplate angle increases the torque capacity but reduces drive shaft speed. Conversely, reducing the angle reduces the torque capacity but increases drive shaft speeds (unless fluid pressure decreases).

## What is a fixed displacement hydraulic motor?

A fixed-displacement pump is a positive displacement type where the amount of displacement (gpm) cannot be varied, only by changing the drive speed to the pump. Since industrial hydraulic systems are usually driven by constant speed electric motors, applications of a fixed-displacement pump are limited.

## Which is the best choice for controlling a hydraulic motor?

Figure 12-25 shows a motor circuit with meter-in flow controls. This is the preferred way to control the speed of hydraulic motors. Use a meter-in circuit whenever possible because the motor’s internal leakage passes to the low-pressure port through internal check valves.

## How do you control the speed of a hydraulic cylinder?

There are three ways to meter the oil flow in order to control the speed of a cylinder, which are: meter-in, meter-out, and bypass. With the meter-in method, the flow control valve is connected in series between the pump and the cylinder, as Figure 1(a) shows.

## How do you troubleshoot a hydraulic valve?

SYSTEM INOPERATIVE

1. No oil in system, insufficient oil in system. Fill system.
2. Wrong oil in system. Refer to specifications.
3. Filter dirty or clogged.
4. Oil line restriction.
5. Air leaks in pump suction line.
6. Worn or dirty pump.
7. Badly worn components (valves, cylinders, etc.)
8. Leakage.

## How do you test a hydraulic valve?

1. The testing valve is switched to an open position.
2. Start recording.
3. Slowly increase the flow of the hydraulic source until the pressure difference exceeds, say, 1 MPa.
4. Slowly reduce the flow of the hydraulic source to a minimum.
5. Stop recording.