Re: Ceramic core resistors

[Terry Fritz <twftesla-at-uswest-dot-net>]

Hi Daniele,

	Put four of your resistors in parrallel on each leg (100 Watts at 1.175K
Ohm).  Just use another set of safety gaps if you don't have the fancy
MOVs.  You "should" be able to get by without the gaps next to the NST but
I always worry...

Cheers,

	Terry

At 11:27 PM 6/6/00 +0200, you wrote:
>Terry, Gary, list,
>Well I now have some ceramic resistors from some surplus stuff.
>So I am not going to build some bombs with the others :)
>they are 4700 Ohm 25 Watts, I have 12 to be exact...
>I asked some friends on series and paralleling resistors to achieve
>higher values, but nobody seems to remember the rules...
>school time is far away and I can't find my old books :<
>So my question is what are the rules to use some resistors
>in the form of a multi resistors net ? (like mmcs)
>Series = more ohms ?
>Parallel = more watts ?
>another question I have, is were to recover som MOVs ...
>I cannot order from digikey... too much money for a poor order,
>as I live in Italy. Is there any apparatus to dismantle to find some ?
>I mean rated 1800 Volts.
>
>Ciao all
>Tnx again
>Daniele
>
>-----Original Message-----
>From: Tesla List <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
>Date: marted́ 6 giugno 2000 7.31
>Subject: RE: FILT1.JPG (Was Terry's NST Filter Network)
>
>
>>Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>>
>>Hi Gary,
>>
>>The file FILT1.jpg was out of date and has been removed.  See:
>>
>>http://users.better-dot-org/tfritz/NSTFilt.jpg
>>
>>I presently use Digi-Key L100J1K0-ND resistors as described at:
>>
>>http://www.digikey-dot-com/EC/V3/387.pdf
>>
>>They are Ohmite 100 Watt 6.5 x 0.75 inch vitreous enamel fixed value power
>>resistors.
>>
>>They have no aluminum heat sinks but are just wire wound on a ceramic core
>>under ceramic glazing.  They should easily stand continuous 20+ kV spikes
>>across their terminals...
>>
>>'Dale' makes similar rated resistors with the gold anodized aluminum heat
>>sinks around them.  At work, they blow out like little shotguns...  I have
>>a dent in my polycarb S-glasses from one of them turkeys...  Very poor for
>>high voltage (any voltage!) especially when Dale screws up and does not
>>center the elements in the silicon potting.  Dropping 480V three phase
>>across one when the internal element is lying against the aluminum case...
>>Grrrrr!
>>
>>But "I" don't use them...  Those Ohmite ceramics are the best out there
>IMHO.
>>
>>Cheers,
>>
>> Terry
>
>