To maintain the pressure in the receiver at a certain level, an air compressor has an automation unit, the so-called governor control – a pressure switch.
This item of equipment turns the engine on and off at the right time, avoiding exceeding the compression level in the storage tank or its value too low.
The pressure switch for the compressor is a unit containing the following elements:
- Terminals. Designed to connect electrical cables to the relay
- Springs. Mounted on adjusting screws. The pressure level in the receiver depends on the strength of their compression
- Membrane. It is installed under the spring and compresses it under the action of compressed air
- Power button. Designed to start and force stop the unit
- Connection flanges. Their number can be from 1 to 3. Flanges are designed for connecting the compressor enable relay to the receiver, as well as for connecting a safety valve with a pressure gauge to them
In addition, the automation on the compressor may have additions:
- Discharge valve
- Thermal relay
- Time relay
- Safety valve
The principle of operation of the switch is as follows. After starting the compressor motor in the receiver, pressure begins to rise. Since the air pressure regulator is connected to the receiver, the compressed air from it enters the membrane unit of the relay. The membrane under the action of air bends upward and compresses the spring. The spring, compressing, activates a switch that opens the contacts, after which the unit engine stops. When the compression level in the receiver decreases, the membrane installed in the pressure regulator bends down. The spring unclenches, and the switch closes the contacts, after which the engine starts.