Glassmike cap as MMC / Tesla Coils / Forums

Forums

4hv.org :: Forums :: Tesla Coils

« Previous topic | Next topic »

Glassmike cap as MMC

1 2 next

Move Thread

LAN_403

Tom540

Mon Jun 18 2007, 10:03PM

Banned on 3/17/2009.
Registered Member #487 Joined: Sun Jul 09 2006, 01:22AM
Location:
Posts: 617

Hey all,

Just curious if anyone has tried using this type of cap as an MMC. http://cgi.ebay.com/26-Rare-GLASSMIKE-HV-CAPACITOR-5KV-01MFD-ASG103-5M_W0QQitemZ220115446068QQihZ012QQcategoryZ29833QQrdZ1QQssPageNameZWD1VQQcmdZViewItem I have a few at home one is rated at .01uF @ 10kv and thought it might be worth a try for a small coil. I thought I'd ask before trying it tonight after work. They seem like they might explode and throw glass everywhere.

Terry Fritz

Mon Jun 18 2007, 11:44PM

Registered Member #393 Joined: Tue Apr 18 2006, 12:30AM
Location:
Posts: 297

Hi,

They seem like they might explode and throw glass everywhere.

I have never played with them, but Glassmike and flying glass explosions are almost synonymous in Tesla coil and high RMS current use!!!

Terry

Hazmatt_(The Underdog)

Tue Jun 19 2007, 01:57AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

Okay, look, if you don't have the experience with the product, why on earth are you telling someone how it fails???

I have used Dearborn glass capacitors for Tesla Coil use. 5KVDC caps in a string as my pulse network.

They DO work for SHORT run time, but they get warm or hot.

HOW THEY FAIL, for all you people who do not have experience with these capacitors :

They fail this way, The capacitor is undergoing a tremendous amount of stress because its a FILTER capacitor, NOT a pulse capacitor. The dielectric gets hot from the AC current going through them, which causes some swelling of the body of the capacitor. The capacitor is rolled very tight and is somewhat tight in the glass tube, so when it gets hot there is quite a bit of force exerted on the glass tube.
Two or three of the caps in the string will get very warm, and one or two will POP, NOT Explode. Let me be very clear, they will Burst with a POP sound. Glass does not fly far, nor fast, but I did notice a piece of glass about 2 feet away at times. The high viscosity oil in the cap prevents the glass from traveling far.

So now you know.

Limit use to under 10 minutes, limit use to 3 second bursts with 10 seconds between bursts minimum.

Coronafix

Tue Jun 19 2007, 02:14AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

I would class bits of glass 2 feet away as flying glass.
If you can't use them for long bursts because they "pop", explode, whatever,
then why use them at all? And why make such a fuss at correcting a technicality
that is technically correct? If anything, you've made it clear why not to use them!

Hazmatt_(The Underdog)

Tue Jun 19 2007, 02:19AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

Goldspehere, When I began Tesla coiling 10 years ago, these were the only economically feasable capacitors to me.

Again, they do not explode, Am I talking to myself here?! They burst with a POP and the majority of the glass falls directly below.

Goldsphere, Explosion infers Bodily Harm. POP or Bursting of MY capacitors in MY Experience (something not debatable here) had little or no chance of bodily harm other then being cut by glass.

You are right that I advise NOT to use these capacitors because they are not suited for Tesla coil use, but if you must use them because its what you can afford, keep them cool in an oil bath in a plastic container.

Another note: You will hear the tesla coil spark gap with a particular 'Bang' and as the capacitors get hot that sound will change very slightly, and if you pay close attention to this you can stop your run short of a burst.

Terry Fritz

Tue Jun 19 2007, 03:02AM

Registered Member #393 Joined: Tue Apr 18 2006, 12:30AM
Location:
Posts: 297

Hi,

Okay, look, if you don't have the experience with the product, why on earth are you telling someone how it fails???

After ten plus years of "having" to "hear out" the complaints about it and a number of injuries..., and noting the trends... and after fighting really hard for five years to push plastic MMCs... I listened, and never bought that crap... I "heard" and "made the art far better"...

I really can calculate capacitor RMS current to less than 1% and I know what most current manufactures "do" and "say" from direct talks in "pleasant and "VERY" unpleasant " situations with them... I helped make the MMc because of older tech explosions and dangers... I think I am sort of an "expert" in this situation...

ANY high power cap in a glass or non safety venting technology these days is just "stupid"... "Glassmike" is infamous for dangerous explosion events... The explosion can almost be calculated to the second...

So don't mean to be harsh, But let's not get anyone else hurt by pushing to many RMS currents into these "glass grenades"... A stupid idea that should be forgotten now... Plastic shrapnel is pretty safe, but the new plastic cap never blow up anyway...

Why even bother with this dangerous and stupid type of capacitor... Thing are much better "now" due to MMCs...

Terry

Hazmatt_(The Underdog)

Tue Jun 19 2007, 03:30AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

Say what you will, I have been there myself.

Tom540

Tue Jun 19 2007, 03:54AM

Banned on 3/17/2009.
Registered Member #487 Joined: Sun Jul 09 2006, 01:22AM
Location:
Posts: 617

LOL well thanks, I'm not going to use them now. That's kind of what I expected to hear. I did try it out but the coil was untuned and only running of a 60 volt bench supply. They'll probaby still be here 10 years from now, heh maybe some day i'll find a use for them. I did have one crack once from over volting them. I just didn't want to waste any of my good MMC caps on this junk coil im building.

Terry Fritz

Tue Jun 19 2007, 04:05AM

Registered Member #393 Joined: Tue Apr 18 2006, 12:30AM
Location:
Posts: 297

Say what you will, I have been there myself.

Cool!

But I chose to "call you out" on this safety issue...

"Liability" for "dumb remarks" and actions can run into the 100's of millions of dollars... But no one should be "allowed" to get hurt from well known dangers...

Why "defend" that which is "stupid", in light of that which is "bright"... Just because "you" were not killed as a child, does not prevent you from killing other children from promoting old dumb ideas...

We must express the "best thoughts and ideas the best we know them"...

If there is a danger, it is "our duty" as the "knowledge bearers" to deflect those that follow from those well known dangers!!!

In my case, anyting that has to do with "Glassmike" is a danger!!! And I tell all there to just "run away"...

Terry

Hazmatt_(The Underdog)

Tue Jun 19 2007, 04:56AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

Terry.... take a minute to read my posts, you might just find that I said Dearborn.

So don't go off on me half cocked.

You can call me out all you like. I speak from experience. I'm not BS-ing anything here.
I myself HAVE 'blown up' 2 Glassmike capacitor and 8 Dearborn capacitors. How many have you 'blown up'?

Take a minute to read where I said I do not endorse their usage, but if you must, use them for very short run times.

Something else, read everything first, then get angry, okay.

1 2 next

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