When wiring the auto ac compressor, there are many factors to consider for proper electrical connection. The main concern is the amperage requirement of the compressor. This determines the size of the wire. Another factor is whether the compressor has single-phase or three-phase power. This determines the wiring configuration.
Turn off the power and mark, please note that the device is working. Single-phase automotive ac compressors have three slide-in terminals. The terminals are usually marked on the terminal or on the terminal cover. They will be labeled R, which is the running line; S, which is the starting line; and C, which is the common line. In some cases, the terminals may not be marked. You can use a multimeter to determine the winding.
Set your multimeter to the correct ohm setting. Check each terminal with each other. You will take three readings. Write down the reading. Between the two terminals, there will be the highest ohm reading. This indicates that the terminal is located between the start and run windings. This means that the other terminal is common. Connect the wires of the meter to the common terminal and every other terminal. There will be two separate readings. The higher ohm reading is the start winding. The lower reading will be the running winding.
Connect the red wire connecting the capacitor to the start terminal. The black wire leading to the load side of the contactor is connected to the run terminal. The white common wire is connected in series with the overload switch, which prevents the compressor from overheating. The overload may be inside the car ac compressor. If it is an internal overload, the white wire will be connected to the common terminal and connected to the other side of the load side of the contactor.
Connect the common wire to the overload switch (if external). This will be the small CD directly above the terminal.
Clip the ampere meter to the public wire. Turn on the power and check the amperage. When the compressor starts, the ampere will increase instantly, but then the FLA (full load ampere) listed on the nameplate will be read. If the amperage is high, turn off the equipment and call a qualified service technician.
Post time: Nov-09-2020