Agilent Technologies TV 303 Notice De Mode D'emploi page 210

17 Technical Information
Description of the TV 303
The TwisTorr stages are in the form of four discs.
The turbine rotor is supported by permanently lubricated high
precision ceramic ball bearings installed on the forevacuum side of
the pump.
The static blades of the stator are made of stainless steel. These are
supported and accurately positioned by spacer rings.
The TwisTorr stators are in the form of self-positioning machined
discs with spiral pumping channels. These are made of aluminium
alloy.
During normal operation, the motor is fed with a voltage of 54 Vac
three-phase at 1100 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 can be water cooled or air cooled: in the first case the
customer can use the dedicated channels on the pump body, in the
second case an external optional fan is available.
A thermistor sensor is mounted near the upper bearing to prevent
the pump from overheating.
The pump is balanced after assembly with a residual vibration
amplitude, measured at envelope level, of 0.6 m/s
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 (KF 25 – optional).
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3rd stage with a blade angle of 24°,
4th and 5th stages with a blade angle of 20°.
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TV 303 User Manual / 87-901-019-01 (A)