Driver Board Exploded with massive spark

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Driver Board Exploded with massive spark

Postby Mr Holmes » Tue Mar 12, 2019 12:40 pm

Please Help
We have built the one tesla TS and have not managed to get it working
We have confirmed the low power system check buzz
But when we connect the coil we get no spark!
We have checked all the solder joints and still no spark

We tried to look at the waveforms on a CRO between the gate and emitter of IGBT pin 1 and 3
There was a massive spark which toasted the board between the two pins

Now the low power testing doesn’t give us our buzz
What should we do?

When we try measuring across the plus and minus pins of the bridge rectifier
We get 0.75 V and after removing the IC’s we got 0.75V

Help!
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Re: Driver Board Exploded with massive spark

Postby Bayley » Tue Mar 12, 2019 1:38 pm

The IGBT's emitters are not connected to earth - trying to look at Vge with the HV side energized will cause a lot of damage as you effectively short the AC line to ground.
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Re: Driver Board Exploded with massive spark

Postby Mr Holmes » Wed Mar 13, 2019 2:39 am

Do you think we’ll have to start again from scratch with a new driver circuit board?
How should I have set up the CRO to look at the waveforms?
I assumed that I needed the board powered to look at them?
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Re: Driver Board Exploded with massive spark

Postby Bayley » Wed Mar 13, 2019 4:41 pm

You should not look at any waveforms outside of the ones listed in the manual - the list pretty much covers anything of interest on the LV side of the board, which is isolated from mains. It may be possible to repair the board, can you post pictures?
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Re: Driver Board Exploded with massive spark

Postby Mr Holmes » Tue Mar 19, 2019 12:41 pm

What’s the best way to convert my large image file into something 2MB to upload
Basically how do I set up my CRO to study the waveforms produced to check they are right?
I connected it with the fuse out and the fuse holder covered in insulation
When I connected it across the IGBT emitters pin 1 and 3 I got a massive spark which seems to have compromised the Low Voltage test of getting the interrupter to cause a buzz in the primary coil

What is the best way to get it working?
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Re: Driver Board Exploded with massive spark

Postby Bayley » Tue Mar 19, 2019 3:40 pm

You absolutely *cannot* measure the waveforms on the IGBT side unless you have a proper isolated scope. Your best bet is to replace all the socketed IC's - its only a few dollars and will save you a ton of pain in the future.
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Re: Driver Board Exploded with massive spark

Postby Mr Holmes » Wed Mar 20, 2019 1:31 am

Originally before the discharge we were getting the LV buzz and now we get none
We still don’t get 24V at the rectifier even with the IC’s removed
Doesn’t that mean the IC’s are OK?
We’ll replace them and try again
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Re: Driver Board Exploded with massive spark

Postby Mr Holmes » Wed Mar 20, 2019 1:31 am

How do we set up our CRO to look at the waveforms when we are trouble-shooting?
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Re: Driver Board Exploded with massive spark

Postby Bayley » Wed Mar 20, 2019 4:53 pm

LV side waveforms don't need any special setup since LV ground is connected to earth ground.
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