Re: suitable bleeder resistors for MMC

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Shaun,

Here is the testing I did:
==================

Date: Tue, 26 Sep 2000 20:56:08 -0600
From: "Tesla list" <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com
Subject: MMC drain resistor study


Original poster: Terry Fritz <twftesla-at-uswest-dot-net>

Hi All,

	I fired up the Bertan HV power supply and tested some 10Meg ohm  1/2 watt
YEGEO resistors from DigiKey at high voltage.  The results of a typical run
are:

Volts DC	Current (mA) 	Power	R(Mohms) Comments
1000		0.115		0.115	8.695
1200		0.138		0.165	8.696
1400		0.161		0.225	8.696
1600		0.184		0.294	8.696
1800		0.208		0.374	8.654
2000		0.233		0.466	8.584
2200		0.261		0.574	8.429
2400		0.290		0.696	8.276
2600		0.320		0.832	8.125
2800		0.351		0.982	7.977
3000		0.389		1.167	7.712	Drift
3200		0.428		1.370	7.477	Drift
3400		0.476		1.618	7.143	Drift
3600		0.548		1.973	6.569	Drift
3800		0.617		2.345	6.159	Drift	Hey! what's burning!
4000		0.684		2.736	5.848	Drift up, then down
4200		0.701		2.944	5.991	Drift down
4400		0.719		3.163	5.841	Drift up
4600		0.762		3.505	6.037	Drift all over
4800		0.815		3.912	5.890	Drift all over
5000		---		---		she on fire now! ;-))

So It looks like they are perfectly good to 1600 volts and probably to 2000
RMS.  That is like 2828 AC!  This is at the low end of the Bertan's range
so there is probably some significant calibration error but you get the
idea... 

I also tested two 1600 volt 0.56 uF Panasonic caps and they broke down at
4100 and 4800 volts and seemed to self heal in stride...  Numbers like
these explain why MMC's are so darn tough!!

Cheers,

	Terry


At 11:21 PM 2/21/2002 -0600, you wrote:
>I was wondering what the groups stance is on the 10 MegaOhm resistors that
>are used on the Geek Group MMC.  If we assume 2000 Volts max and 10 megaohms
>across each cap--  the power is only 0.4 watts, but a 1/2 watt resistor, the
>next size up,  is only rated a few hundred volts.  I've seen some resistors
>made by  IRC that will handle ~ 3kv at 1/2 watt, I'd have to check the exact
>specs but they'd work, the only thing was they were very expensive, $3 to $4
>Canadian each .  What resistors are people using since my MMC capacitors
>didn't come with resistors?  I want to get some that will be reliable, easy
>to get ahold of and cheap!
>
>Shaun Epp
>
>