High Voltage Resistors

To: "'Tesla List'" <tesla-at-pupman-dot-com>
Subject: High Voltage Resistors
From: Tesla List <tesla-at-stic-dot-net>
Date: Sun, 1 Feb 1998 15:28:55 -0600
Approved: tesla-at-stic-dot-net

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From:  davmckin [SMTP:davmckin-at-ix-dot-netcom-dot-com]
Sent:  Sunday, February 01, 1998 5:30 AM
To:  Tesla List
Subject:  Re: High Voltage Resistors



Tesla List wrote:

> ----------
> From:  Peter Naor [SMTP:QVR1.PETE-at-worldnet.att-dot-net]
> Sent:  Friday, January 30, 1998 7:55 PM
> To:  Tesla List
> Subject:  High Voltage Resistors
>
> Hi to all!
>
> There is a lot of Email regarding capacitors and construction method
> thereof!
>
>  I am interested in High Voltage resistors, non-inductive and their
> composition! Is there a "home brew" type composition that will allow
> control over resistor value, tempco and voltage rating?
>
> Regards,
> Peter Naor

Dear Peter & all,

Non inductive resistors may be obained through a company EBG
(listed in the Thomas Register).  Non-inductive resistors are
manufactured
by tracing the resistive element back and forth 90 degrees to the axial
direction of the resistor.  Think of it like winding a secondary of a
tesla
coil one direction for one turn and the back the other direction for the

next turn and so on.  They do this until the desired resistance is
obtained.

As far as homebrew, there are a couple of methods by which HV
resistors are made.  One method uses very distilled water in which
salts are added to create the desired resistance.  These are mainly
used at very high voltages & are placed on the output HV terminals.
The other method, a homebrew type, resistor could be made using
many resistors stringed together and submerged in oil.  Calculate
the final resistance needed.  Then using available resistors (usually
in the 10's k-ohm range)  add up how many would be required to sustain
a voltage of approximately TWICE that your looking at measuring.  Then
using a tracking distance of 15 kV / in. along each individual resistor,

string enough of them in series to be below that required value.

 The most important note here, is that when stringing resistors, is to
keep
the potential across each resistor below a maximum value of 15 kV / in.
And for Tesla Coild work I would recommend backing that off to even
10 kV / in. - just for added measure.

David L. McKinnon
High Voltage / Transformer Engineer

E-mail:  DavMcKin-at-ix-dot-netcom-dot-com