Re: HV Probe

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

Original poster: "Scott Hanson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <huil888-at-surfside-dot-net>

Matt -

The original Tek P6015 probe (not the "P6015A" version) needed to be charged
with Freon 114 (1,2-dichlorotetrafluoroethane) to achieve its 40 kV peak
pulse capability. Freon 114 is no longer readily available, and there is no
known substitute that will retain the original calibration of the probe. A
quantity of liquid Freon was placed in the resistor chamber and the cover
installed. The liquid Freon vaporized and filled the chamber with Freon gas,
which created an insulating blanket around the divider resistor.

I believe the probe is derated to only 12 kV peak voltage (~8500 V RMS) if
no dielectric fluid is used. The chamber that contains the divider resistor
& the Freon is sealed with O-rings, but the Freon will slowly diffuse
through the seals and be lost. Used probes may have deteriorated O-rings or
tiny scratches in the surfaces that the O-rings seal against that increase
the leak rate.Unless you re-charge the probe with Freon before each use, you
never really know how much Freon is in the chamber. If you are measuring
voltages in excess of 12 kV and the probe is low on Freon, you may have a
flashover in the resistor chamber that destroys the probe, the measuring
equipment connected to it, and puts the operator at high risk if he is
touching any part of the measuring circuit.

Tek also made a P6013 HV probe that appears physically identical to the
P6015, but that did not use any dielectric except air in the resistor
chamber. It was rated for 12 kV peak.

Regards,
Scott Hanson
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, November 06, 2002 10:23 AM
Subject: HV Probe


 > Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Mddeming-at-aol-dot-com>
 >
 > Hi "TEK"-ophiles,
 >         I am looking at an ad for an "almost-new" Tek P6015 HV probe. It
 > says, "Comes with all accessories except the can of Freon". I've never
used
 > a probe that needed Freon before. Of what significance is this? Does it's
 > absence degrade the ratings? If so, can something be substituted? What?
 > How? etc.,etc.
 >
 > Experience-based replies appreciated.
 >
 > Matt D.
 >
 >