Agilent Technologies TwisTorr 74 FS Notice De Mode D'emploi page 294

17 Technical Information
Description of the TwisTorr 74 FS
The TwisTorr stators are in the form of selfpositioning machined
disks. On each disk there are parallel spiral pumping channels
designed to pump in centrifugal direction on one side and in
centripetal direction on the other side. These are made of aluminium
alloy.
During normal operation, the motor is fed with a voltage of 54 Vac
three-phase at 1167 Hz. To reduce losses during start-up to a
minimum, the frequency increases according to a ramp with a higher
initial voltage/frequency ratio.
The pump must always be cooled before starting using it. Running the pump
WARNING! without cooling it could damage inside components.
The pump can be water cooled or air cooled: in the first case an
external optional water cooling kit is available (model X3502-68002 ,
X3502-68003 ), in the second case an external optional fan is
available (model 9699290). A thermistor sensor is mounted near the
upper bearing to prevent the pump from overheating.
If the thermistor reading exceeds 60 °C the pump fails and stops with
Error Code = 2. If the thermistor reading is below 0 °C, the pump
fails and stops with Error Code = 1 (see Controller Manual),
The pump can operate in any position and can be supported on the
high vacuum flange. The connection of the forevacuum on the side of
the pump is a KF 16 NW flange.
294/352 TwisTorr 74 FS User Manual / 87-901-053-01 (A.00)