[Sneap] GVM needed for General IonX Tandetron

[Chris Westerfeldt]

Howard,
I am not at all familiar with General Ionex GVM units but electrically this
sounds just like the HVEC units.  They employ a Rotron motor.  I do not know
if they are still available or not however.  I had a motor fail last year
but had a spare and I have not investigated getting the failed one repaired
yet.  We have used both the four-blade and nine-blade versions of the HVEC
GVM and they both used the same modified Rotron motor.  I will look tomorrow
for the model number.  I wonder whether Quintin¹s Kessel¹s machine has the
same GVM motor (see SNEAP post on 1/11)?
Regards,
- Chris
-- 

Chris R. Westerfeldt
Research Scientist / T.U.N.L. Radiation Safety Manager
Duke University Physics Department &
Triangle Universities Nuclear Laboratory
Science Drive, Box 90308
Durham, NC  27708-0308
Tel: (919) 660-2600
Fax: (919) 660-2634
Email: Cwest at Tunl.Duke.Edu



From: Howard Evans <hevans at ues.com>
Reply-To: Symposium of Northeastern Accelerator Personnel
<sneap at tunl.duke.edu>
Date: Wed, 16 Jan 2008 16:25:43 -0500
To: Symposium of Northeastern Accelerator Personnel <sneap at tunl.duke.edu>
Conversation: GVM needed for General IonX Tandetron
Subject: [Sneap] GVM needed for General IonX Tandetron

SNEAPers: 

The motor in the Generating Volt Meter (GVM), used to monitor and provide
negative feed-back control of the terminal voltage in our 1.7 MV Tandetron,
has stopped working after only twenty-seven years. Does anyone reading this
message have a complete GVM assembly (including the weldment that attaches
to the side of the accelerator tank) they don't need? It doesn't have to be
in working order, although that would be nice. If we have to replace these
things every twenty-five or thirty years, I would like to have a spare on
hand.

Actually, what I really need right now is the motor. All I know about it at
the moment (before I open the tank later this week) is it is a split-phase
induction motor, with a 4 microfarad oil-paper phase-shifting capacitor,
operating on single phase 208 VAC. It is General Ionex Corporation part
number A-08723, which is probably meaningless in 2008, but may have made
sense to someone in 1981 when it was penciled into a drawing.

As someone posted earlier in this forum, regarding ordinary versus premium
bearings, we would like to invest in a motor with "premium" bearings in the
hope that the motor will operate for a longer period of time.

I tried using the terminal voltage monitoring tap on the voltage-grading
resistive divider to control the terminal potential... it seems to have been
designed for this purpose originally... but the results are not
satisfactory. The ion energy wanders at will and seemingly randomly. We want
to do an implant that will take several days to complete, but we cannot
spare someone to continuously monitor and re-adjust the beam energy and/or
position. So I need to get this GVM repaired or replaced as soon as
possible, if not sooner.

Howard B. Evans, Jr.
Engineer, Materials Laboratory
UES, Inc. 
4401 Dayton-Xenia Road
Dayton OH  45432-1894

937-426-6900 ext. 116 (office and voice mail) or ext. 121 (lab)
937-426-5718 fax 

hevans at ues.com e-mail
http://www.ues.com web site

"Things should be explained as simple as
possible, but not simpler." -- A. Einstein

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