Three lines of air conditioning pressure switch, how to control, what are the three lines, respectively
One of the public, an open (normal) signal, a customs (overpressure) signal, and some air conditioning motherboard integrated electronic detection, crystal clock detection operating pressure, three lines than the two lines of sensitive detection, real- In the high-end, variable capacity, variable frequency refrigeration equipment.
The pressure switch is usually three lines, one 12v. The other two are a high voltage switch, one is the atmospheric pressure switch, the pressure is too high will disconnect the compressor electromagnetic clutch high voltage 1.4MPA, low voltage 0.147MPA, high pressure side pressure Higher than 1.4MPA, high-voltage switch to open, so that the fan high-speed turn, not because of high pressure damage to the system. The pressure is lower than 0.147MPA, then the compressor does not work ah, so that will not damage the compressor.
A line of fire, a zero line, there is a pressure switch line, that is, to say that the pressure set above the line there is electricity. Then the electricity on this line is passed through the relay to the compressor.
1, there are many kinds of car air conditioning lines, models different control methods are different, but as you said the three lines to the compressor should be Toyota cars, its control principle is: air conditioning switch is turned on from the fan switch any gear (The compressor), the pressure sensor (mounted on the high pressure pipe), the compressor lock sensor, also known as the speed sensor (installed on the compressor), the air conditioner amplifier, , The engine speed sensor, etc. as an input signal, (automatic air conditioning also added: ambient temperature sensor, indoor temperature sensor, engine water temperature sensor, sun sensor, etc. as an input signal) to control the compressor electromagnetic clutch relay, cooling fan relay, After the relay delivers power to the compressor and the cooling fan, the air conditioner starts working.
2 when the pressure is too low when there is no one will pass, these are signal lines, to go through the relay after the electrical appliances.
3 vacuum before adding the oil directly into the compressor, the traditional approach is to first vacuum, and then use the table plus tube (yellow) to open the low-pressure valve to the oil into the low-pressure pipeline, this approach is not desirable , Because most of the oil at this time into the evaporation box, when the start air conditioning, the compressor prone to "liquid hit" accident.
