1. Installation location

The installation positions of the compressor and outdoor fan capacitor are shown in the figure. The compressor and outdoor fan are installed inside the outdoor unit, so the compressor capacitor and outdoor fan capacitor are also installed inside the outdoor unit, and are installed in a specially designed electrical control box for the outdoor unit.

The main parameters of the compressor and outdoor fan are shown in the figure.

① Capacity: determined by the power of the compressor or outdoor fan, that is, different capacitors with different capacities are selected for different powers. The usage specifications of common capacitors are shown in the table below.

② Voltage resistance: Capacitors operate on alternating current (AC) power sources with a voltage of 220V, so the voltage resistance value is usually 450V (450VAC) for AC.

③ CBB61 (65): It is a non-polar polypropylene film AC capacitor with advantages such as good stability, resistance to impact current, strong overload capacity, low loss, and high insulation resistance.

　　3. Overview

① English symbols: Fan capacitor (FAN CAP), compressor capacitor (COMP CAP).

② Function: The compressor and outdoor fan are used during startup. When a single-phase motor is powered on, the capacitor is first charged, causing the current in the starting winding of the motor to run 90 degrees ahead of the winding, generating a rotating magnetic field, and the motor starts running.

③ Characteristics: Due to being an non-polar capacitor, the two sets of terminal blocks have the same function and are not divided into positive and negative when used.

④ The following table shows the corresponding relationship between the cooling capacity of the air conditioner and the starting capacitance of the compressor.

⑤ The speed of the fan is not related to the capacitance capacity. The factor that determines the fan speed is the number of coil poles. The idea of increasing the fan speed by increasing the capacitance capacity is not advisable and can easily damage the fan coil due to overheating. The number of poles in the fan coil corresponds to the rotational speed (r/min)

⑥ When replacing fan capacitors and compressor capacitors, they should be selected based on the original capacitor capacity and withstand voltage value. The withstand voltage value is generally 450V AC, and the capacity error should be within 20% of the original capacity. If the difference is too large, it is easy to damage the motor

　　4. Compressor capacitor terminal block

The connection terminals of the compressor capacitor are shown in the following figure. There are two sets of wiring terminals above, each consisting of two pieces, connected to the starting and running windings of the compressor coil, regardless of their orientation. Only one piece is used in one group, connected to the starting winding (yellow wire); Due to the direct connection of the N neutral wire (blue wire) to the operating winding (blue wire), one piece of the capacitor in the other group is connected to the operating winding and the other piece is connected to the N neutral wire of the four-way valve coil.

(1) Judging the compressor capacitor based on its appearance

The capacitance of the compressor is shown in the following figure. If the bottom of the capacitor bulges and is shaken left and right on a table (flat surface), it indicates that the capacitor has no capacity damage and can be replaced directly. A normal capacitor has a flat bottom and is very stable when placed on a desktop.

If the bottom of the capacitor bulges, it must be damaged and can be replaced directly; If the bottom of the capacitor is flat, it cannot be said to be absolutely normal, and other methods should be used to detect or replace it.

(2) Charge discharge method

The charging and discharging method is shown in the following figure. Connect the terminal of the capacitor to two leads, connect an AC power supply (220V) for about 1 second to charge the capacitor, and then short-circuit the two ends of the leads to discharge the capacitor.

Judging the fault based on the discharge sound: ① The sound is very loud, but the capacitor is normal; ② The sound is weak and the capacity is reduced; ③ No sound, the capacitor has no capacity.

(3) Multi meter testing

Due to the lack of capacitance detection function in ordinary multimeters, measuring with resistance gear can easily cause misjudgment. Therefore, a multimeter or instrument with capacitance detection function should be selected to detect the capacity.

The capacitance measurement gear of the multimeter is shown in the above figure (a). This example uses a VC97 multimeter from a certain brand,zuiThe large detection capacity of 200nF is characterized by the ability to directly detect non-polar capacitors using multimeter probes; Unlike some other brands or models of multimeters, which require connecting capacitors to leads and inserting them into detection holes for testing.

The above figure (b) shows the capacitance range of the VC97 multimeter, measured in nF (nanofarads) and uF (microfarads), with a conversion relationship of 1uF=lOOOnF.

Measure the capacitance with a multimeter as shown in the following figure. When testing, turn the multimeter to the capacitor position, disconnect the power supply of the air conditioner, unplug the leads on the two terminals of the compressor capacitor, and use two probes to directly measure the two terminals. Taking the capacitor labeled with a capacity of 30uF as an example, the measured capacity is 30.1uF, indicating that the tested capacitor is normal.