RE: [TCML] SISG Repair

["caspina" <caspina@xxxxxxxxx>]

I haven't taken it apart yet.

I must add it is a triggered sisg (triggered with SCR's and little
transformers at the gates, your idea)
The coil was running fine, I interupted it and restarted few seconds later,
no streamers this time but the lights at the ceiling went out and on and out
and on... at a rate of 4-5 times/sec clearly because of power surge but the
fuse didnt' blow.

There was no smell, sisg wasn't hot (it's in a box with a fan).
There's no visual damage at all and when I put an ohm-meter over the
components I get the same values
as when I do with another, identical sisg I have(6 modules for a small
coil), execept for the IGBT's of course.

The TC is a 6" dc-resonant charging coil with only 6kV power supply, but
4MOT's (for power) and 30uF smoothing cap.
I use fluorescent ballasts as charging choke.
Since I use it frequently for audio modulation I kept the charging choke
rather small: a string of 4 ballasts parallel
with another 4 ballast string gives me +/- 1.5 H.

Maybe 4 is not enough to withstand 6 kV and they arced inside and caused the
failure... can't see that
and with ohm meter it's still the same value as a new one (20 ohms /
ballast).

Nevertheless it worked fine for months now, even after I pushed the coil to
it's limits: http://www.youtube.com/watch?v=ZTc43rHwUm0
After such a run the air that comes out of the box is warm, but not really
hot and cools down very rapidly.

I hope it's only the IGBT's otherwise I have a lot of soldering to do :(

The reasen why it failed is something else. For the moment I can only blame
the Charging Choke...


Michael.





-----Original Message-----
From: Finn Hammer [mailto:f-h@xxxx]
Sent: woensdag 6 juli 2011 15:17
To: Tesla Coil Mailing List
Subject: Re: [TCML] SISG Repair


Michael,

It would be interesting to know whether it is the IGBT or the sidac/
tranzorb string that is broken. Is there any smoke outlet, cracked case
or other physical sign of damage visible?.

-Finn Hammer

----- Original meddelelse ------

> Fra: caspina <caspina@xxxxxxxxx>
> Til: TCML pupman <tesla@xxxxxxxxxx>
> Dato: Ons, 06. jul 2011 13:33
> Emne: [TCML] SISG Repair
>
> Hi list
>
>
> I have a SISG coil, SISG = 15 modules (15kV)
>
> Now 6 Modules are shorted and need to be replaced.
> I'm not sure what to do with the others...
> Could they be 'partly damaged' but still work for a certain time ?
> Best to
> replace all modules, maybe even everything?
> Has anyone experience with this?
>
> Michael.
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla



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