What causes a pure sine wave Inverter to shut down after switching on with no load and no errors displayed. 

Not clear but it could happen when you have no right continuity to all parts. I had that problem and I could solve it, however, it happens to me the same from a bigger issue. Usually the inverter stops due safety reasons, does it switch off and on repetitively?

Hi, no when you switch it on it displays the voltage for a second then switches off. It always gave an error code if bus voltage was low or overload but since last week without any occurrence I noticed it was off and when I switched it on it started with this issue. After a few tries it blew the fuse. I opened up and replaced the fuse but the issue persists. I found that the 4 mosfets (nce15td60) had blown, all four. I replaced them with Fdp2532 's and checked gate drivers and all is in order there. On the voltage boost side I found one of the two mosfets had shorted. It's two G025n06' s and I tried putting two Fdp2532's in there but same thing, turns on then switches off. Displays DC voltage then switches off, and silent, no alarm. 

5 minutes ago, Wayne Cioccale said:

On the voltage boost side I found one of the two mosfets had shorted. It's two G025n06' s

Are you sure? These seem to be rated at 60 V, which is nowhere near enough for a power factor correction boost circuit.

But perhaps I misunderstand what you mean by "voltage boost side".

@Psy

6 minutes ago, Coulomb said:

Are you sure? These seem to be rated at 60 V, which is nowhere near enough for a power factor correction boost circuit.

But perhaps I misunderstand what you mean by "voltage boost side".

It's a 12v 500 watt so it has the the high frequency transformer and two mosfets. The drains on the centre tap and the sources on the ends of the primary side. 

How I understand is they drive the transformer. The gate drivers test all good but I can't find a replacement for the 2x G025n06. I figured that the gate drivers aren't configured for the Fdp2532 mosfets. 

The Fdp2532 's are suitable for the Inverter bridge as replacement according to all transistors cross reference. 

When I switch on and measure with the dmm at the two filter caps after the secondry of the transformer I should get around 330 v but I only get 4 volts. 

26 minutes ago, Wayne Cioccale said:

It's a 12v 500 watt so it has the the high frequency transformer and two mosfets. The drains on the centre tap and the sources on the ends of the primary side. 

How I understand is they drive the transformer. The gate drivers test all good but I can't find a replacement for the 2x G025n06. I figured that the gate drivers aren't configured for the Fdp2532 mosfets. 

The Fdp2532 's are suitable for the Inverter bridge as replacement according to all transistors cross reference. 

When I switch on and measure with the dmm at the two filter caps after the secondry of the transformer I should get around 330 v but I only get 4 volts. 

Can you disclose the make and model of this inverter.? 

Fivestar FS-I003. PS0512. 500 WATT. 12VDC. 220V 

30 minutes ago, Wayne Cioccale said:

Fivestar FS-I003. PS0512. 500 WATT. 12VDC. 220V 

Ok thanks,  you will need an oscilloscope to check if the gate drivers are firing the mosfets on the battery low side, and if so if there is switching on the  mosfets (12v chopped by the mosfets that drives the primary windings). 

If there is only 4v on the DC bus then it probably means the low side mosfets are not switching. 

Make sure you have a current limited 12v supply instead of battery, when testing. 

Edited January 13, 20232 yr by BritishRacingGreen

Thanks, so you mean the Fdp2532 can work but there's a problem with the gate drivers. I don't have an oscilloscope, I tested the components with a dmm when the mosfets were out. The smd's and all measure up but I'm not sure 100% about the smd transistor pairs. I've tried 4 pairs of mosfets with no success. I have a pair of IRFB4115 mosfets in at the moment. Worst of all is the Inverter is not even a month old and I'm not exactly sure what caused the issue in the first place. I had a smaller modified sine that still going fine which is utilized in the exact same way. 

25 minutes ago, Wayne Cioccale said:

Thanks, so you mean the Fdp2532 can work but there's a problem with the gate drivers. I don't have an oscilloscope, I tested the components with a dmm when the mosfets were out. The smd's and all measure up but I'm not sure 100% about the smd transistor pairs. I've tried 4 pairs of mosfets with no success. I have a pair of IRFB4115 mosfets in at the moment. Worst of all is the Inverter is not even a month old and I'm not exactly sure what caused the issue in the first place. I had a smaller modified sine that still going fine which is utilized in the exact same way. 

Yes, unfortunately you dont know if the PWM signals are even generated in the first place, and sadly thats where you need oscilloscope. 

I havent checked the spec of the mosfet, but 30v or upwards at 60A or upwards seems ok, seeing the configuration has 2 mosfets. 

 

 

2 hours ago, Wayne Cioccale said:

The drains on the centre tap and the sources on the ends of the primary side. 

Typically the centre tap is hard connected to battery positive. The two ends of the winding are switched to battery minus via drain-source of a mosfet. The mosfets are triggered  out of phase with respect to each other. 

If the high side is only 4v and the transformer and/or mosfets are not hot, then it tells us that the mosfets are not chopping. 

EDIT: i take it that small inverters like this have no built in charger, or do they? 

Edited January 13, 20232 yr by BritishRacingGreen

Thanks very much for the advice, seems like I'll have to send it in. 

What could've caused the issue in the first place. And there wasn't even a sign of any physical damage. 

Just now, Wayne Cioccale said:

Thanks very much for the advice, seems like I'll have to send it in. 

What could've caused the issue in the first place. And there wasn't even a sign of any physical damage. 

I wish i could help you, but i dont even know if the machine has a microprocessor or if it is basically a PWM hardware design. In either case it could be the controller  itself that is disabling the function. 

Has the inverter an lcd screen with buttons? 

7 minutes ago, BritishRacingGreen said:

I wish i could help you, but i dont even know if the machine has a microprocessor or if it is basically a PWM hardware design. In either case it could be the controller  itself that is disabling the function. 

Has the inverter an lcd screen with buttons? 

Is it possible to send us a birds eye view of the PCB? 

Heya, these little inverters can be annoying... as mentioned by @BritishRacingGreensome additional info will go a long way here, since there are a million ways these could be operating so without seeing how it does things it's hard to help. I picture of the PCB will help, maybe do front and back if you can since they like to place the MOSFET drivers underneath the MOSFETs...

However, I will tell you what I told someone else in another post... MOSFETs are sensitive and fickle, when one burns they all need to be replaced.

If this is using a MOSFET rectifier, which many do but there are just as many that don't, then any micro-misalignment will cause the voltages to to move and the effects can stack. This could be why you're getting such little voltage... I was working on one of these, replaced the DC MOSFETs and the drivers popped. Replaced the drivers and the controlling IC popped, replaced that and turns out the AC MOSFETs were actually damaged with the initial pop even though none of them looked burned or damaged...

17 hours ago, BritishRacingGreen said:

I wish i could help you, but i dont even know if the machine has a microprocessor or if it is basically a PWM hardware design. In either case it could be the controller  itself that is disabling the function. 

Has the inverter an lcd screen with buttons? 

I see I've made a mistake, the Fdp2532 are a suitable replacement for G025n06 (the transformer chopper mosfets). The Inverter bridge takes 4 x igbt's nl. NCE15TD60B (I put the 4 mosfets here and seems to be a challenge to find. Do you perhaps know what could work as a replacement. I'll first get that in order once I've got all the components and then let you know. 

Cheers 

Wayne 

Hi Wayne did you ever managed to source those IGBT's. I have the same inverter same issue. In my case I am almost convinced the issue was caused by a phasing issue. I was switching over with a automatic dual power ATS. I suspect that the live and neutral phases got switched around when I fisrt installed the inverter and this caused the issue. Same blown fets and igbt. Now just truffling to find the igbt or equivalent.