Agilent Technologies TPS-compact, User Manual

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Technical Information
184 Agilent TPS-compact User Manual
Turbopump Description
The turbopump consists of a high frequency motor driving a turbine fitted with
many bladed stages and Twistorr drag stages. The turbine rotates in an
anticlockwise direction when viewed from the high vacuum flange end.
The turbine is made of high-strength, light aluminium alloy, and is machined from a
single block of aluminium. The Twistorr stages are in the form of 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 fabricated in stainless steel. These are supported
and accurately positioned by spacer rings.
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 functions with a power feed at 54 Vac three-
phase at 1167 Hz (74 FS) or 1010 Hz (305 FS). To reduce losses during start-up to
a minimum, the frequency increases according to a ramp with a higher initial
voltage/frequency ratio.
A thermistor sensor is mounted near the upper bearing to prevent the pump from
overheating. The pump is balanced after assembly with a low residual unbalance
amplitude.
Controller Description
The integrated controller is a solid-state frequency converter which is driven by a
single chip micro-computer and is composed of a PCB which includes a power
supply with a 3-phase AC output, analog and input/output section, microprocessor
and digital section. The controller recognizes the mains presence and converts the
single phase AC mains supply into a 3-phase, medium frequency output which is
required to power the pump.
The controller can be operated by a remote host computer via the serial
connection.