Always tripping the fuse / Tesla Coils / Forums

Forums

4hv.org :: Forums :: Tesla Coils

« Previous topic | Next topic »

Always tripping the fuse

1 2 next

Move Thread

LAN_403

waicool20

Tue Jul 22 2014, 08:51AM

Registered Member #40981 Joined: Thu Nov 21 2013, 08:40AM
Location: Hong Kong
Posts: 12

My DRSSTC is always tripping the fuse, but i've checked the wiring numerous times and ive probed almost everything no shorts or anything. It tripped the breaker once but that was due to a faulty IGBT, after replacing it, all 13 A fuses go off, any ideas guys?

Ill answer any questions about my coil asap if any

Mads Barnkob

Tue Jul 22 2014, 09:13AM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

It certainly sounds like you still have a short somewhere in your circuit, hence the fuses blow.

When you ask for help, supply all possible information, schematics, pictures, video, everything! How are we to help you by only guessing?

Describe it all in detail, do not just say you will tell if asked to specific parts. If you want help, you have got to do some work yourself!

waicool20

Tue Jul 22 2014, 01:26PM

Registered Member #40981 Joined: Thu Nov 21 2013, 08:40AM
Location: Hong Kong
Posts: 12

Ok so yeah I said I would give out any details you guys needed I just didn't know what to give.

Everything is almost based on Steve's schematics.
Bridge:

Driver:

Grounding:

Rectifier used: GBPC2504W ( Having 220V input but somehow I find it rectifying to 200V for some reason, any ideas?)
Datasheet:

Smoothing Capacitors: B43740A9108M000 (3 of them connected in parallel, giving 3000uF @ 400V )
Datasheet:

IGBTs: FGH80N60FDTU ( 80A 600V )
Datasheet:

Coil specifications:

-Tank Capacitor: 940C series ( 0.1uf, 2000v ) Total Rating: 0.2 uF @ 4kv ( A little bit worried this is too low but on a budget :/ )

-Secondary Radius: 2 inches | Height: 25 inches ( Approx 2000 winds using AWG 30 enamled Cu wire )

-Primary Radius: 5 inches ( Vertical Coil ) | Height: 3 inches ( Calculated 4.5-5 windings required for resonance, Standard 1/4" Cu Tube )

-Toroid: 5 inch minor, 14 inch major ( Used the cheap method of buying some Al air duct and using conductive tape to smooth it )

All the circuitry is wired as the above schematics and I've probed everything with my multimeter from taking apart the bridge to reassembling it there are no shorts whatsoever.

Here is a picture of the final build:

Most of my build progress that I documented is on that site.
Hope you guys can help me!

Ps: Somehow the links don't work when I click on them ( some plugin error ) so just to be sure just copy them and paste it manually

Mads Barnkob

Tue Jul 22 2014, 03:35PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

I fixed the links in your post, if you use the [_link_] tags, write your url where it says url and the link text inbetween, else just write the url and it turns into the green arrow by itself.

Looking at your bridge PCB I noticed there are some places with very short distance between DC+ and DC-. Are you sure there is not some place it can arc over? There is a small black spot on the side of the caps between the traces.

Are you using silpads on all the IGBTs?

Is there missing a IGBT? I see no legs at one of the spots for the switches in the picture of your bridge.

waicool20

Wed Jul 23 2014, 01:33AM

Registered Member #40981 Joined: Thu Nov 21 2013, 08:40AM
Location: Hong Kong
Posts: 12

Hmm black spot can you point out where it is ? I can't seem to find it.

As for the IGBTs yes I have mica sheets on them and the heatsink themselves have the black insulation paint. And those photos of the bridge are only partially populated since I had a shortage of the IGBTs at the time.

Ive been thinking about the arcing, how much of a gap should I leave because the PCB wasn't really the best, I guess I'll use a cutter or mill and widen the gaps manually.

Though I suspect I wired my GDTs wrongly which can lead to wrong phases etc and cause shoot through? though I don't think this is the problem as I have powered up the bridge separate from the driver yet it the problem persists

Mads Barnkob

Wed Jul 23 2014, 05:49AM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

The black spot here:

The spacing from screw and washer going through in the top right corner, minimal:

Distance between the traces out at the edges looks dodgy:

Do you use gate resistors?

Anodized aluminium is not isolated! It is not a black paint, anodizing sure makes for a bad conductor, but it is far from being a isolating part.

Feathers

Wed Jul 23 2014, 05:49AM

Registered Member #10052 Joined: Thu Feb 07 2013, 11:31PM
Location: Overland Park, Kansas
Posts: 78

When does it blow fuses/trip breakers? When you plug it in, or give an interrupter signal?

waicool20

Thu Jul 24 2014, 12:08AM

Registered Member #40981 Joined: Thu Nov 21 2013, 08:40AM
Location: Hong Kong
Posts: 12

I think the black spot is just my marker line outs and i have as according to schematic have zeners back to back and 2.1 ohm resistors on the gates. I'll try removing the washers and widening the gaps and see how it goes.

And yes it blows the fuse immediately after i give power to (with interrupter disconnected) it so I'm sure there is a short somewhere but I just cant seem to find it.

The breaker only flipped once due to a bad IGBT

Sigurthr

Thu Jul 24 2014, 01:54AM

Registered Member #4463 Joined: Wed Apr 18 2012, 08:08AM
Location: MI's Upper Peninsula
Posts: 597

Place an ohm-meter across the DC rails, it should present a very high resistance. If it presents a low resistance or short, it is time to start removing components one by one until the resistance goes high.

I would remove the GDT first, then the IGBTs one by one, then the diodes, then the caps. If the board is bare and still showing low impedance, you know that it has to be at fault.

teravolt

Thu Jul 24 2014, 02:18AM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

is this a solder bridge?

you could use a incandescent lamp or a series resistor in combination with a variac till you get a handle on it. If it were me I would go over the bridge closely to make shore the way you've laid out the bridge because it looks like a short. In bridges when one fet goes the other does.

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob