How to Handle In-Vacuum and Cryo Stepper Motors
24
MA 1203-A010 EN
8 Conditioning In-Vacuum Stepper Motors
8.1 Overview
To remove volatile organic substances from the motor materials, an outgassing procedure
is executed with UHV stepper motors. Outgassing is adapted to the specified requirements
of the stepper motor. During the
Baking Out,
the motor is baked out in an oven in dry ni-
trogen. During
First Outgassing
and
Degas
(shortened heating), the motor is heated by
powering the motor windings in vacuum.
The outgassing temperature at
First Outgassing
and
Degas
is set by the motor current. It
should be equal to the maximum rated stepper motor temperature.
Rule of thumb: Each 100 Kelvin outgassing temperature increase gains one decimal pow-
er of outgassing rate.
8.2 Baking Out (Option)
Alternatively to first outgassing, HV stepper motors can be baked out in dry nitrogen before
placing into operation. The stepper motor is externally heated up to the maximum rated
temperature.
This Baking Out is recommended as an option for Phytron HV stepper motors.
8.3 First Outgassing (Standard)
A First Outgassing is performed in vacuum environment at 10
-6
mbar pressure with all
UHV stepper motors (not UHVC) by Phytron. The phase current is varied to hold the wind-
ing temperature at 200 °C for 24 hours.
For the other vacuum motor types, First Outgassing is an order option.
8.4 Degas (Option)
Degas is a short heating of the motor windings (about 5 minutes) to maximum temperature
before each placing into operation. After a corresponding cool-down time the stepper mo-
tor can be operated up to 50 K below the Degas temperature without emitting volatile sub-
stances.
Degas can be ordered as option.
