Edwards XDS46i

controlled by an inverter, which manages the supply of current to the motor in
accordance with operang condions, and allows the pump to be connected to a single-
phase supply. The voltage changeover switch beneath the voltage changeover switch
cover (item 8) must be set to the correct posion in accordance with the power supply
being used, refer to Connect the pump to the electrical supply on page 19.
The pump is opmised for maximum pumping speed at inlet pressures between 1 mbar
and 10 mbar (refer to Figure: Performance characteriscs on page 12). The pump is not
suitable for prolonged operaon at inlet pressures above 40 mbar; for pump-down of
large volumes; or for rapid cyclic duty. Such operaon may cause the pump to become
hot or the inverter to reduce the motor speed. The pump will speed up again aer the
load is reduced. Maximum rated connuous operang pressure at 40 °C ambient is 12
mbar.
The pump is air-cooled by a fan (item 3) mounted at the opposite end to the motor. The
fan will connue to run for one minute aer the pump is switched o. The pump
incorporates a thermal protecon device that will stop the motor in the event of thermal
overload, for example, high ambient temperature. The pump will restart aer it has
cooled down.
2.4 Gas ballast control
To pump high vapour loads, gas ballast can be delivered into the pump to prevent
condensaon of the vapour carried by the pumped gases.
Air can be introduced to the low vacuum stages through the gas ballast control (item 2).
Alternavely, an inert gas such as nitrogen can be supplied through a suitable external
valve and by using the appropriate adaptor, available as an accessory, refer to Gas
ballast adaptor on page 34.
The gas ballast control has three posions:
▪
Closed (posion '0')
▪
Low ow (posion 'I')
▪ High ow (posion 'II')
2.5 Construcon
The pump scrolls are made of anodised aluminium. The motor housing is aluminium. All
surfaces of the pump which are exposed to the pumped gases are free from copper, zinc
and cadmium.
Other materials of construcon include uorocarbon elastomer, nitrile, chemically
resistant polymers, nickel, stainless steel and a PTFE composite material.
Page 10
A73101880_F - Introducon