Electrical Gauges And Sending Units
The electrical gauges and sending units operate in electrical balance. The voltage and resistance are important to obtain the correct reading on the gauges. The sending unit converts temperature or pressure into electrical resistance. The sending unit changes the value of the resistance according to the change in temperature or pressure.
Sending Unit For Water Temperature
Illustration 1 | g00506047 |
The sending unit is in a series circuit with the electrical gauge. The sending unit will change the value of the resistance according to the temperature. When the temperature is low, the resistance is high. The sending unit must be in contact with the coolant. The sending unit will not work correctly if the coolant level is too low.
Sending Unit For Oil Pressure
Illustration 2 | g00505955 |
The sending unit for oil pressure is an electrical resistance. The sending unit will also change the value of resistance according to the pressure. The sending unit for oil pressure is in a series circuit with the electrical gauge. As the pressure on the sending unit changes, the reading on the gauge changes.
Electric Service Meter
Illustration 3 | g00874815 |
The electric service meter is self-powered. A magnetic pickup is mounted on the flywheel housing in order to provide voltage. The voltage will provide power to the electric service meter. The electric service meter records hours of operation. A separate magnetic pickup must be used for the service meter. The same magnetic pickup cannot be shared with the following components: tachometer, electronic governor and electronic speed switch.
Air Shutoff Solenoid
A solenoid changes an electrical input into a mechanical output. The air shutoff solenoids are used to release a plate assembly in the air inlet pipe to a closed position. This stops the engine. The air shutoff solenoid can be automatically activated by an engine overspeed condition or the air shutoff solenoid can be manually activated by pushing an emergency stop button. A solenoid has a winding. If the winding is energized, the solenoid will shut off the engine. The air shutoff solenoid does not have the hold-in windings. A high current is necessary to pull the plunger into position, and the same current level is used to hold the plunger at this position. This type of solenoid must not be activated constantly for a time period of more than 2 1/2 minutes, or damage to the solenoid will result.