Common maintenance methods for inverters - Solutions - Huaqiang Electronic Network

Photocoupler

1, ten general maintenance methods:
● Look: Look at the fault phenomenon, look at the cause of the fault, and look at the whole board and the whole machine;
●Quantity: use a multimeter to measure the device, the solder joint, and the tin point;
●Measurement: measurement waveform, upper tooling test board;
●Listen: The sound of the relay is connected, and the inductor transformer contactor has no howling;
● Touch: touch IC, MOS tube, transformer is overheated;
● Broken: refers to disconnecting the signal connection (disconnecting the printed circuit or the pins of some components);
● short: short a certain control signal to another point;
●Pressure: The fault may disappear after the hand is pressed due to the weak welding of the plate or the looseness of the connecting piece;
● Knock: This method has a good effect on judging whether the relay is moving or not;
●Release: Discharge the capacitor before removing the resistance of the board or the resistor.
2, common causes of failure:
● Production of repaired veneers: virtual soldering, continuous soldering, device mounting, device misassembly, device damage, device missing. ●
The whole machine that is sent for repair: the device is knocked out, the plug is not in place, the wire is connected incorrectly, and the device is damaged.
● Spare parts board: The device is damaged.
● Spare parts: The device is damaged.
3, maintenance experience description ● As the saying goes: good memory is not as bad as a pen. Knowledge is valuable and the experience is higher. If you have good skills, both can be.
● Experience only represents the past, and the future phenomena and causes are endless, so experience can't fix all the machines.
● Experience can give you directions when you have no way to start. But you can't rely on experience alone, and you still have to go by yourself.
● When the whole machine reports a fault, first take the control board to the simple tooling to try it. Or use the replacement board to determine which board is broken or the module is broken.
4, the common maintenance experience of the inverter. (taking the Emerson series inverter as an example)
1. Description before maintenance:
The meaning of the abbreviation referred to below. "Red" refers to the red test pen of the multimeter, "black" is the black test pen, "two" is the diode file, "Europe" is the ohm file, the unit after all data is volt, "+" refers to the positive bus, "-" refers to the negative Busbar, LN or RST refers to the power input, and UVW refers to the power output.
2. Important steps before powering up:
(One step) to judge the quality of IPM. Use the second gear, red connect -, black to connect RSTUVW, the value is about 0.5 is good, black is connected +, red is connected to RSTUVW, the value is about 0.5 is good. If it is not 0.5, the IPM will be broken. If it is 0.5, it can only indicate that the freewheeling diode in the IPM is good. At this time, measure the optocoupler coupled with the IPM: use the second gear, the red pin 5 pin, the black pin 6 pin, the value is about 0.55 is good, then Red is connected to 7 feet, black is connected to 8 feet, and the value is about 0.77. This shows that the optocoupler and IPM are good. If the optocoupler is broken, the IPM is also broken. If the IPM is broken, the general optocoupler and associated resistors and diodes will also be bad.
(Two steps) Judging whether the switching power supply MOS is good or bad: seeing the gate resistance burnt or the measured gate resistance value has changed, indicating that the gate resistance and the MOS and associated 2844 are broken. If all power is changed after replacement, there is no display or display, but the fan is overspeed (high voltage is high), the four-pin optocoupler of PC9 may be broken. If one or two steps are good, the inverter still has no display. It is very likely that the diode of the switching power supply is broken. The method for judging whether the diode is good or bad is as follows: red is connected to the anode of the diode, black is negative, one type is 0.4-0.5 is good, and the other type is 0.2-0.3 is good. If the switching power supply is broken: the power-on fan does not turn, the voltage is low, and the forward and reverse of the D3 diode is 0.14 - the diode is bad.