Agilent Technologies 9698905, User Manual

Page: 202 / 234

17 Technical Information
Description of the Turbo-V 81-T
202/234 Turbo-V 81-T User Manual / 87-900-984-01 (G)
Proceeding from the high vacuum to the forevacuum region, the
turbine stages sequence is:

1st stage with a blade angle of 40°,

2nd stage with a blade angle of 30°,

3rd stage with a blade angle of 24°,

4th and 5th stages with a blade angle of 18°,

6th stage with a blade angle of 14°;

7th, 8th and 9th stages with a blade angle of 12°.
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.
During normal operation, the motor is fed with a voltage of 54 Vac
three-phase at 1350 Hz (max). 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 a dedicated external plate made of nickel-plated
brass, 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 less than 0.01 µm.
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.