Fault Analysis and Detection Methods on Defective Pure Sine Wave Inverter?

The following six situations are normal:

1. turn on: when turn on the inverter, the buzzer will beep once, red led light on for a few second, then green light keeps on.

2. low input voltage alarm: when the input voltage is lower than 11.0V±0.5V, the buzzer will beep twice, at this time, the green light keeps on like when turn it on, the output is normal, the inverer can work.

3. low input voltage protection: when the input voltage is lower than 10.5V±0.5V, the buzzer will beep three times, at this time, the inverter off AC output and the red light on.

4. over input voltage protection: when the input voltage is over than 15V±0.5V, the buzzer will beep four times, at this time, the inverter off AC output and the red light on.

5. temperature protection: when the temperature of the inverter is over 45℃±5℃, the cooling fan will run; when the temperature is over 80℃±5℃, the buzzer will beep five times. at this time, the inverter off AC output and the red light on, the fan will keep running.

6. over load protection: when the inverter is with load, the buzzer will keep beep for about 10times constantly, the green light is still on, when the beeps stop, the red light will be on, about after 8seconds the inverter will restart again. Sometimes both the red and green light on, low input voltage, but without alarm.

Need to open the inverter to check the inside circuit boars when has the following situations:

1. red light off, green light on, without output:

a. check the output socket to see if there has any loosing connections.

b. check the IC on the C1 board near the AC side to see if there has any IC is not tightly connected, check the 15V power supply on the C1 board to see if it is normal, if yes, then tru to replace the crystal on the C1 board.

2. green light off, red light on. If alarms, then need to check as the above situations; if not alarm, then need to check the followings:

a. check the mosfet on the DC side(RU4099 on 12v type, and 05CN10 on 24v type), and their corresponding diode(P6KE39A on 12v type, and P6KE75A on 24v type), and also check the 10 ohm resistor.

b. check the mosfet on the AC side(IRFP4232,G80N60 on 110v item, G40N60, G80N60 on 220v item), if they are burnt, then need to check their corresponding 2.2 ohm resistor and diode 1N4148, also the IC（IR2110 or IR2113）on the C1 board.

c. if there has short circuit when connected the battery but not turn on, then there has damage on the mosfet on the DC side(RU4099 on 12v type, and 05CN10 on 24v type) and the diode (P6KE39A on 12v type, and P6KE75A on 24v type), if there has short circuit when connected the battery and turn on, then there has damage on the rectifier diode of the high voltage position.

3. no response on both the red and green light:

a. check if the switch cable is loosing or not, the slot line is tightly plugged or not.

b. check if the DC fuse is disconnected, if yes, then need to check the DC mosfet and the diode on the high voltage position(U8100E, RHRP8120,RHRP1560,RHRP29-06) to see if they are burnt or not.

c. check the two power supply(13V and 15V) on the small DC board are normal or not, whether there has any damaged component.

4. both green light and red light on(or green light on, red light flickers)

a. check of it is over load protection, if yes, then it will alarm as well, and the AC output voltage reduce, because of over load, at this time, need to test with small load. When run inductive load and with air compression type load)the surge maybe about 10-15times), turn on the inverter, the red light will flicker, after about 10seconds, if the output voltage is normal, also it works well when run other load, then the inverter is ok.

b. if the output voltage is normal, the inverter works, then the transistor(SS8050) or other related component broken, this will not affect the use of the inverter.