Re: REQ for info (HV insulating fluid) (fwd)

---------- Forwarded message ----------
Date: Fri, 24 Jul 1998 08:03:21 -0700
From: Jim Lux <jimlux-at-earthlink-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: REQ for info (HV insulating fluid) (fwd)

> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: REQ for info (HV insulating fluid) (fwd)
> Date: Thursday, July 23, 1998 9:02 PM
> ---------- Forwarded message ----------
> Date: Thu, 23 Jul 1998 17:51:30 +0100
> From: R M Craven <craven-at-globalnet.co.uk>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: REQ for info (HV insulating fluid)
> I have just acquired a wideband HV 'scope probe, a Tektronix P6015.
> The probe will work upto 13kV unfilled, or 40kV when filled with a freon
> insulating fluid. These ratings are for the total DC and AC peak, upto
> 75MHz.
> The freon is no longer available due to bans on CFCs etc. so I have some
> questions to allow me to find something equivalent, if i eventually need
> do so.
> 1. Does anyone know the name, number or spec. of the original grade of
> which was used? I need to know the dielectric strength and also the rel.
> permittivity.
> 2. Can anyone suggest an alternative fluid?

Without knowing the actual Freon used, perhaps we can come up with a guess.
Was it actually a liquid at room temperature and pressure, or is it under
pressure in the enclosure. 

What is the vintage of your probe? That will help determine the
possibilities, because the various freon's were introduced in different

Actually, if it is just a pressurized gas at an 30 psi  or so, I would try

Even though they are greatly restricted, you can still get some Freon's for
this kind of application.

Have you called Tek? They have a justly deserved good reputation for
customer support. I have called them for info on ancient (but still
working) equipment, and it may take some time, but they always call back
with the info.