4.2
Standby
You can press the Standby button on the EXC300M Controller to operate the pump at reduced
rotational speed. Select Standby before or after Start-up, for any of the following reasons:
·
To extend safety bearing life and still maintain adequate vacuum pumping performance (for
example, when you leave a system under vacuum over holiday periods)
·
To increase system pressure or to extend the maximum inlet pressure range of the pump
where this suits a particular process
·
To avoid pump excitation of any resonances which may exist on sensitive instrumentation.
4.3
Shut-down
Note:
In an emergency only, open the vent-valve quickly to decelerate the pump rotor in the shortest
possible time.
Shut down the EXT250M as described below. Refer to the EXC300M Controller instruction
manual where the backing-pump and accessories are automatically controlled by the EXC300M
Controller.
1.
Switch off the backing-pump and press the Start/Stop switch on the EXC300M Controller to
switch off the EXT250M.
2.
If a suitable vent-restrictor is fitted, turn the manual vent-valve anticlockwise to open it. If a
suitable vent-restrictor is not fitted, wait until the pump speed has fallen to 50% of full
rotational speed, then turn the manual vent-valve anticlockwise to open it.
3.
If water cooling is in use, turn off the cooling-water supply.
EXT250M Turbomolecular Pump
23
