the probe comes in contact with "HOT" electrical component. They are easily obtained from automotive jobbers or discount stores.
c. Continuity Light:
Continuity Light is like a test light but contains its own battery power source. It is used for testing electrical circuits when the components are not connected to a battery. They are easily obtained from discount stores or electrical jobbers at modest cost.
d. Volt Meter:
A DC volt meter, as used in automotive repair business, is a good investment for trouble shooting problems that are related to low voltage. They are used in two ways:
1.One probe is grounded while the other is used to probe the "HOT" leads; the meter shows the voltage available at the point where the second probe is connected.
2.Second: They can be used to measure a voltage drop in a wire; in probe is connected to one end and the remaining to the other end; the reading is the voltage drop.
e.OHM Meter:
An OHM meter is used to measure resistance and is very useful tool when working on wire circuits and solenoid coils. On some coils the wire resistance is up to a level where a DC test light might show an open circuit and it really is not so. An infinite meter reading on any test light shows that the circuit is open. A coil test, however, will always show some value of resistance but it must not be infinite. All tests conducted with an OHM meter must be done with the battery disconnected from the system.
10.Hydraulic Fluid
a. The Purpose of Oil:
The main purpose of hydraulic fluid is to transfer power from the pump to the actuators but it must also perform many other tasks which are critical to a well designed system. First the oil must have good lubricity or be "slippery" so that the friction will be as low as possible to metal to metal wearing at a minimum. Second, the viscosity or "thickness" must be in the proper range at the operating temperature so that unwanted leakage will be at a minimum, but will still allow the oil to lubricate the close fitting parts in the system. (Oil that is too thin will leak past seals, valve spools and the gears; oil that is too thick will not flow properly and cause the pump to cavitate or starve.) Third, the oil must be compatible with the seals used in the system. Fourth, there should also be additives in the oil to slow down the effects of rust, oxidation (oxygen in the air combining with the oil
44