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My first DRSSTC

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Danielle

Sun Jul 08 2007, 04:56PM

Registered Member #632 Joined: Mon Apr 09 2007, 01:09AM
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Posts: 267

Steve should I wait and do more testing before first burn test or can I proceed. remember that wave form is without the IGBT load and the cap is the one specked in EVR's mini brute design off of the gate drive chips. the GDT is made from a re wound comp PSU transformer.

Danielle

Sun Jul 08 2007, 08:58PM

Registered Member #632 Joined: Mon Apr 09 2007, 01:09AM
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Posts: 267

ok so I am almost finished all I need to do is mount the heat sinks on the IGBTs I will get them tomorrow afternoon. here is a pic of the final setup.

Ken M.

Mon Jul 09 2007, 12:49AM

Registered Member #618 Joined: Sat Mar 31 2007, 04:15AM
Location: Us-Great Lakes
Posts: 628

I think it looks great, although I'm a bit concerned that it may be a tad top heavy, or have a high center of gravity, and that it may topple over damaging one or more parts, other then that, it looks great hope to see some good looking arcs off that.

Danielle

Mon Jul 09 2007, 04:42AM

Registered Member #632 Joined: Mon Apr 09 2007, 01:09AM
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Posts: 267

the coil is balanced and I bolted it to the case I tried to topple it and you caint easly while it is on the ground but here is a pic of it running with out the power electronics at night I love blue leds

Steve Ward

Mon Jul 09 2007, 05:26AM

Registered Member #146 Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055

Hook it up to the IGBTs and post a new picture.

I worry that perhaps your ferrite core may have a gap in it since it was from a switching power supply.

Steve Conner

Mon Jul 09 2007, 08:57AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

I think it's more likely he used the yellow iron powder donut core that we tell everyone not to use for a GDT

I agree those gate drive waveforms look chronic, but I can't picture exactly why or what would cause the weird oscillation after the burst. Whatever, I think it warrants more investigation before firing the thing up.

Danielle

Mon Jul 09 2007, 04:42PM

Registered Member #632 Joined: Mon Apr 09 2007, 01:09AM
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Posts: 267

thank you all I decided to purchase the correct ferite core for the job for now can I use some 1:1:1 GDT from coil craft I have they function perfectly.

edit

also because they are 1:1:1 I will only get 15V waveforms do I need to replace the zeners and TZS to compensate or should I just make a good 1:2:2 GDT as I tested the one from coil craft and there is no ringing and it looks as it should un loaded.

Danielle

Mon Jul 09 2007, 08:16PM

Registered Member #632 Joined: Mon Apr 09 2007, 01:09AM
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Posts: 267

ok so I mad a new GDT and here it is it is ferrite with a 1:2:2 ratio

edit

after reading a bit and seeing information on grounding I had a few questions:

- do I want to connect the mains ground to the control circuit ground?

- do I connect the neg of the HV power section to mains ground through a filter cap?

- is this all that I need to do because I am done all I need to do is mount the heat sinks and fans on the IGBTs

Thanks,

Daniel.

edit

I finished I just need to know if I need to do those things I listed in the questions I will test the low power section on the scope again wensday and then fire it up wensday night

edit

here are some pics of the cooling sistem MMC and primary

Danielle

Thu Jul 12 2007, 05:18AM

Registered Member #632 Joined: Mon Apr 09 2007, 01:09AM
Location:
Posts: 267

ok so I got everything connected but when I tried it out I turned it on the florescent light I put on top flickered for a fraction of a second and then I saw the over current LED go on for another fraction of a second and then nothing I raised the voltage and I got one arc and then nothing I have to completely re set the hole thing every time I try it. I think it has something to do with the over current setting I set it for 2.2V I am using a half bridge of 30N60s with huge heat sinks I also fixed the wave form problem I had the hole thing messed up. I would like to know if it could be something als but I would like to have it running.

edit

its working but no arcs yet just enough power for the florescent light I just need to raise the over current. I raised the over current and now I could draw 6" arcs but the IGBTs failed but they were cold

edit

I finally got it working I am working on tuning it but right now I hear alot of noise but I see very little spark I see about 1/2" streamers.

Danielle

Fri Jul 13 2007, 04:06AM

Registered Member #632 Joined: Mon Apr 09 2007, 01:09AM
Location:
Posts: 267

ok so now I am getting 18" arcs and a 6" spray into the air here are some pics

edit

I have now gotten 18" spray into the air and can draw 20" arcs at 80% AC input. this is only a half bridge of 30N60s and the heat sinks aren't even getting warm.

it finally works I will take better pics later.

edit

a good pic of 16" spray

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