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18
Technical Information
Description of the TV 903 Pumping System
262/306 Turbo-V 903 Pumping System User Manual / 87-901-016-01 (A)
Pump Description
The pump consists of a high frequency motor driving a turbine fitted with 5
bladed stages and 2 Macrotorr stages. The turbine rotates in an anticlockwise
direction when viewed from the high vacuum flange end.
The turbine is made of high-strength aluminium alloy, machined from a single
block.
The Macrotorr stages are in the form of two 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 Macrotorr stators are in the form of self-positioning machined discs with
pumping channels and an opening restricted by the corresponding rotor discs.
These are made of aluminium alloy.
During normal operation, the motor is fed with a voltage of 27 Vac three-phase
at 800 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 has to be air-cooled and an external fan is available.
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 = 1 (WIN 206). If the thermistor reading is below 0 °C,
the pump fails and stops with Error Code = 0 (WIN 206). See Window
Meanings section for details.
The pump is balanced after assembly with a residual vibration amplitude less
than 0.01
μ
m.
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 25 flange.