Single-phase asynchronous motors are commonly used: capacitor operation, capacitor start, capacitor start, capacitor operation, and resistance (phase separation) start. The schematic diagram is shown in Figures 1, 2, 3, and 4. Damage to the capacitor will cause the motor to start, the operation is weak, and the sub-burning group will be faulty.
The author uses an example to talk about the premise of no mechanical failure of the motor. Troubleshooting caused by damage to the capacitor.
Example 1: Wuhan XXD-120 washing machine motor. The noise does not turn.
The machine is a single-phase capacitor-operated 4-pole motor. The capacitor and the secondary winding are connected in series and then connected to the main winding in parallel, as shown in Figure 1. The motor does not turn, it may be caused by bad running capacitance, open circuit or short circuit of the sub-burning group. First remove the capacitor, use the multimeter R × 1k block test, found that there is no charge and discharge capacity. Use the multimeter R×1 to measure the three wires drawn by the motor. The red and blue wires have a resistance of 27n, the yellow and blue wires have a resistance of 27n, and the red and yellow wires have a resistance of 54n, indicating that the primary and secondary windings are good. After replacing the CBB60 type 1O F capacitor, the fault is removed.
Example 2: Shanxi C02-90L～2 1.5HP motor, supporting woodworking planer,
The motor does not turn.
This machine is a single-phase capacitor-start asynchronous motor. After the capacitor and the secondary winding and the centrifugal switch are connected in series, the circuit is connected in parallel with the main winding, as shown in Figure 2. According to the single-phase capacitor starting principle analysis, the motor may not be turned on, the capacitor may be broken, the secondary winding may be short-circuited or open, and the centrifugal switch may be opened. Set the reverse switch to the middle position and remove the starting capacitor. Use the R~I of the multimeter to measure the resistance of the main winding U1-u2. The secondary windings W1-W2 are connected in series with the centrifugal switch in the motor casing, and the resistance is normal, as shown in Fig. 5. Use R~100 to measure the pin movement of the capacitor, indicating that the capacitance is not enough. After replacing the CD60 type 200 startup capacitor, the fault is eliminated.
Example 3: Zhengzhou Y90L-2 3kW motor, supporting feed mill, the power supply is running normally, and the feeding is stopped.
This motor is a capacitor start capacitor running asynchronous motor. The principle is shown in Figure 3, and the wiring board connection is shown in Figure 6. Remove the W2U1 and U2V1 connecting pieces, remove the lead of the starting capacitor and the running capacitor from the Wl terminal, and measure the U1-U2 main winding and the W1-w2 secondary winding with the multimeter ohms. The resistance is normal, V1V2 is away from an Ii, and the switch is open. The starting capacitor C is normal, and the running capacitor C has no charge/discharge capability. After replacing the CBB60 type 40b [F running capacitor, the fault is eliminated.
Example 4: Shenzhen E0-90L1—4 1.1kW motor, supporting wood planer. The power supply is noisy and powerful. After a few minutes, the motor burns high and the electric passenger burns and then bursts. This machine wiring is shown in Figure 6. Set the reverse switch to the stop position and remove the start capacitor and running capacitor. The main winding U1-U2 is measured, the resistance of the secondary winding W1-W2 is normal, the centrifugal switch connector VIV2 is zero, and the running capacitance c is good. Replace 150/. LF capacitor test machine, the fault remains. It is suspected that the centrifugal switch is not separated, and the starting capacitor is inserted into the secondary winding to participate in the operation, resulting in a high current of the motor. When the machine is tested again, the motor will not hear the closing sound of the centrifugal switch "click" when it stops, and the switch can not be separated from Ii. Disassemble and observe the centrifugal switch contact bond. Replace the centrifugal switch and 150/. After the LF starts the capacitor, the fault is eliminated.
Example 5: Shanghai Y90L-2 2.2KW motor with corn thresher. Light load can run, stop it with a little load, and it is powerless. Wiring reference Figure 6, remove the two connecting pieces on the terminal board, use the multimeter to block the main winding U1 - u2, the secondary winding Wl - W2, the resistance is normal, the centrifugal switch is open, the starting capacitance is good, but the running capacitance c When the needle swing is small, the capacitance measured with the capacitance meter is only s F, indicating that the capacitance is reduced. Replace the CBB60 type 30/. After the LF runs the capacitor, the fault is eliminated. Example 6: Shanghai YL100-2 3KW motor, supporting the apricot peeling and sorting machine, turn on the power motor, and the security guard will immediately trip. The owner said that the security device tripped during operation, shorted the user security device, and the watch box security device tripped. The maintenance department said that the motor cable is connected to the iron and needs to be changed. Because I didn’t smell the burnt smell during use, I didn’t believe that the motor would burn. Deliberately sent for maintenance. Use a shaker to measure the terminal to the insulation resistance of the case is ON. Because the apricot kernel selection machine works on wet apricot processing, it has a lot of water and is easily damp. Poor insulation of the motor is common. However, it is not possible to eliminate the failure of the centrifugal switch to remove the wire from the casing or the ground, t2, the switch spring, etc., and disassemble the machine. Observe that the centrifugal switch is good, the main and auxiliary winding wires are not discolored and burnt black, and there is no sign of moisture ingress. Then check the iron on the terminal board. Determine the joint location, remove the W2U2, U1VI connecting piece,
The U1 is measured to be good to the ground, and the W2 is zero to the casing. The C self-capacitance W2 is removed to the casing. Remove the C capacitor and the W2 secondary winding is normal. Is the running capacitor connected to the iron? Then the operating capacitor is taken out from the simple capacitor box. The lead end of the capacitor is broken by the fixing screw, and the screw just against the capacitor lead terminal is connected to the casing through the capacitor bracket. The measured capacitance is good. The capacitor is taken out from the line end with a rubber pad. After fixing with a short screw, the fault is eliminated.
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