Edwards T-STATION 85

Gas ballast control (E2M1.5)
Use the g
as ballast control to change the amount of air (or inert gas) introduced into the low
vacuum stage of the pump.
Use of the gas ballast will prevent the condensaon of vapours in the pump; the condensates
would contaminate the oil.
Use the gas ballast control (Figure 1 on page 10, item 2) closed:
• to achieve ulmate vacuum
• to pump dry gases.
Turn the gas ballast control six turns an-clockwise to open it fully.
Use the g
as ballast control open:
• to pump high concentraons of condensable vapour
• to pump high concentraons of condensable vapour
When operang the pump with the gas ballast control open, there will be an increased rate of
oil loss from the pump.
Electrical supply failure
WARNING:
Risk of injur
y or death. If the power supply fails when the pump is running, the impeller
could connue to spin for approximately 10 minutes. The control circuit may not give any
indicaon that the impeller is sll running.
If the electrical supply to the T-Staon 85 fails when the turbo pump is rotang, the motor of
the turbo pump is used as a g
enerator. The regenerated power is used to maintain the control
system and the display. The regenerated power is not used to maintain the T-Staon 85 control
system or the display.
When power to the control system is lost, no indicaon will be given about pump rotaonal
speed, yet the impeller may sll be turning.
The s
ystem will not restart when the power is reinstated.
D395-94-880A - Operaon
Page 25