Principle and detection of fixed-frequency air-conditioning compressor capacitance and outdoor fan capacitance

1The installation locationthe installation location of the compressor and outdoor fan capacitor is shownCompressors and outdoor fans are installed in outdoor machines, so compressor and outdoor fan capacitors are also installed in outdoor machines and in the outdoor machine's specially designed electronic ally boxes2The main parametersthe main parameters of the compressor and outdoor fan, as shown in figure(1) capacity: determined by the power of the compressor or outdoor fan, i.edifferent power uses different capacities of capacitanceThe usage specifications of common capacitors are shown in the table below(2) voltage resistance: the capacitor operates on an AC supply and has a voltage of 220V, so the voltage resistance is usually AC 450V (450VAC)(3) CBB61 (65): A non-polar polypropylene film AC capacitor with the advantages of good stability, shock-resistant current, strong overload ability, small loss and high insulation resistance3Overview(1) English symbols: fan capacitor (FAN CAP), compressor capacitance (COMP CAP)2: Compressors and outdoor fans are used when starting When a single-phase motor is connected to the power supply, the capacitor is first charged, so that the current in the motor start winding runs 90 degrees ahead of time, resulting in a rotating magnetic field, and the motor will run (3) Features: Due to the non-polarity capacitor, the two sets of terminals act the same, and there is no positive or negative points when used (4) The table below shows the correspondence between the air conditioner cooling capacity and the compressor start capacitance capacity (5) fan speed is not related to capacitive capacity, the factor that determines the fan speed is the number of coil poles, such as by increasing capacitance capacity to increase the fan speed of the idea is not desirable, and easy to damage the fan coil due to overheating The fan coil pole corresponds to the speed (r/min) (6) when replacing the fan capacitor and compressor capacitance, according to the original capacitance capacity and pressure value The pressure value is generally AC 450V, the capacity error should be within 20% of the original capacity, if the difference is too much is easy to damage the motor
4 Compressor capacitor terminal
compressor capacitive terminals see the figure below There are 2 terminals above, each of which is 2 pieces, regardless of whether anyway, the compressor coil start-up and operation winding Group 1 uses only 1 piece, pick-up winding (yellow line), because the N zero line (blue line) directly connected to run winding (blue line), so the capacitor of the other 1 group 1 piece of the pick-up run winding, 1 piece of the four-way valve coil N-end zero line 5 The inspection method (1) the compressor capacitor based on appearance is shown below If the bottom of the capacitor is drummed and shakes left and right on the table (flat), the capacitance is not damaged and can be replaced directly The normal capacitor bottom is flat and stable on the tabletop 　　If the bottom of the capacitor drum is certainly damaged, can be replaced directly, if the bottom of the capacitor is flat, can not be said to be ok, should be used to detect or replace (2) charge-discharge charge-discharge method is shown in the figure below Connect the capacitor's terminals to two leads, charge the capacitor in about 1 second through the AC power supply (220V), and then short the lead to discharge the capacitor at both ends determine the fault based on the discharge sound: (1) the sound is loud, the capacitance is normal, (2) the sound is weak, the capacity is reduced, (3) no sound, the capacitance has no capacity 　　(3) Universal meter detection Because ordinary meters do not have capacitive capacity detection function, the use of electro-blocking measurement is easy to cause miscalculation, so should be selected with capacitive capacity detection function of the universal meter or special instrument to detect capacity 　　The muptable capacitance measurement stop position is shown in figure (a) This example selects a brand of VC97-type multimeter, zui large detection capacity 200nF, characterized by the detection of non-polarity capacitor, the use of multi-purpose table pen can be directly detected; the figure above (b) is the VC97 universal table capacitive, in nF (nanomethod) and uF (micromethod), the conversion relationship is 1uF s lOOOnF measure capacitors with a magnifying meter, see the figure below When detecting the multi-million meter to the capacitor, disconnect the air conditioner power supply, unplug the compressor capacitor capacitor on the 2 sets of terminals on the lead, using 2 pens to directly measure the two terminals, to label the capacity of 30uF capacitance as an example, the measured capacity of 30.1uF, indicating that the capacitance measured is normal