A very frequent cause of hydraulic pump failure is the use of dirty or poor quality oil.
Hydraulic motors are basically the reverse of hydraulic pumps.
CAVITATION is the mixing of water and oil.
CAVITATION is the mixing of air and oil.
Water in hydraulic oil will give the oil a clear look.
A plugged reservoir air vent may cause the hydraulic pump to make a noise.
Air in the system will cause the system to operate slowly.
Low oil level could cause foaming of oil in the hydraulic system.
Dirt in the relief valves will cause high oil pressure.
One disadvantage of a properly engineered hydraulic system is that it is often subject to leaks from high pressure and/or from shock loading.
An accumulator may be used in a system to store energy.
An orifice will create a pressure drop in the hydraulic circuit.
Dynamic sealing is the sealing of an object at rest.
If the down stream side of an orifice is blocked the pressure will equalize on each side of the orifice.
Slight weepage at a dynamic seal is permissible for seal lubrication.
A good safety practice to follow when you begin any troubleshooting or service work on a hydraulic system is to have a container to catch hydraulic fluid.
Schematic drawings of the hydraulic circuits of a piece of equipment are always exact indications of the way the system is configured.
If you are working on equipment manufactured by Caterpillar, it is valid to assume that the hydraulic components will be standard Caterpillar components.
An efficient approach to troubleshooting is to get the disassembly tasks completed first.
When using the flow meter to test the pump, connect the outlet port of the tester to the pressure line.
Damage to hydraulic lines severe enough to cause a system blockage are always visible from the outside.
A leaking pump shaft seal that is allowing air into the pump would probably not be detectable until you do a close inspection of the pump.
Hydraulic systems in which the fluid is confined under pressure are known as hydro-static.
In self-contained hydraulic systems, the volume of liquid displaced in one part of the system is equal to the volume gained in another part or parts of the system.
The air vent in the reservoir does not require a filter because there are other sufficient filters in the system.
The end of pump inlet in the reservoir should be located near the bottom of the reservoir to ensure an adequate supply of oil to the pump at all times.
In a confined hydraulic system, the pressure produced will increase as the area of the input piston decreases.
For a given flow rate of hydraulic fluid, a decrease in the diameter of the line will mean a corresponding decrease in the velocity of the fluid.
The component that converts hydraulic flow and pressure into mechanical force is the:
Flow rate is best defined as:
The component that is driven by mechanical force to create hydraulic flow is the:
The angle that most flared steel hydraulic hose adapters or couplings use is a:
One of the basic principles that accounts for the effectiveness of hydraulic systems is that liquids are:
One of the basic principles which makes hydraulic action almost instantaneous is that liquid is:
When testing a hydraulic system, technicians will monitor and test for:
The man credited with verifying the principles on which modern hydraulics is founded is:
To calculate pressure in a hydraulic system.
For the purpose of this program, hydraulics is defined as the use of:
Hoses most often fail prematurely because of:
A double acting cylinder is a device that converts fluid power into:
The principle of the operation of a hydraulic motor is:
Hydraulic pumps are rated in terms of:
A demonstration system has two hydraulic cylinders connected by a hose. One cylinder is larger in diameter than the other. If the piston in the larger cylinder is pushed down a certain distance, the piston in the smaller cylinder will:
Directional control valves:
The pressure setting of the relief valve is controlled by a (n):
Hydraulic flow is created by:
Hydraulic system filters can be either of two types.
To calculate the area of a circle, you can use either of the two formulas:
What is the area of the big piston end from a cylinder, if the diameter of the piston is 6 1/4"
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