When you say that the anlyser pump is not able to attain the normal rotation speed, may be assumed that the abalyser turbo has some activity??

In our instrumnet (PDZ 20-20), each turbo pump has an electrovalve (Edwards) that is opened by the controller when the instrument is turned off. If the turbo controller or the lead of the electrovalve fails, the valve cannot be closed when restarting the instrument, and then you have a nice leak in your turbo not allowing it to work at its proper speed.

In order to know if you have a problem with the controller of your analyser turbo pump, you can interchange the leads of both controllers (source and anlyser). If the controller of your analyser turbo fails, after the change you should have proper response for the analyser pump while the source turbo know doesn't achieve the proper vacuum.


I hope this helps

José Carlos gonzález Domínguez
Pharmacology REsearch Unit
Institut Municipal d'Investigacions mèdiques
Barcelona
Spain

-----Mensaje original-----
De: Stable Isotope Geochemistry [mailto:[log in to unmask]]En
nombre de Dr. Huiming Bao
Enviado el: lunes, 10 de enero de 2005 23:16
Para: [log in to unmask]
Asunto: [ISOGEOCHEM] Turbo pump problem


Dear folks:
I found my turbo pump unit (TMH 262 and TMH 071) on the analyzer
(MAT253) was off this morning. After   restarting, the turbo unit won't
be able to attain nominal rotation speed, which means that I won't be
able to check source pressure on the mass spec. The back pump (DUO 5.0)
are fine (pumping down to 10 ^ -5 torr). No leak on the line is
detected. A call to Pfeiffer did not seem to indicate that the turbo
pumps are broken. The turbo pumps have been pumping for 2.5 years, and I
don't expect their life is that short.

I know several scheduled and unscheduled power outages during the
holidays were partially to blame, but any suggestion how to fix the
problem will be appreciated.

Best,
Huiming

--
Huiming Bao, Assistant Professor
Department of Geology & Geophysics,
E235 Howe-Russell Geoscience Complex
Louisiana State University
Baton Rouge, LA 70803, USA
Tel: 225-578-3419 (office), -3413 (lab)
Fax: 225-578-2302
http://www.geol.lsu.edu/bao/