© Edwards Limited 2015. All rights reserved.
Page 23
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Operation
D396-20-880 Issue H
4
Operation
4.1
Start-up
Notes:
1. If you wish, you can start the backing pump and the EXT pump at the same time; the EXT pump will not
be damaged and can operate as an effective baffle. However, if the system pressure remains too high
for the EXT pump to reach 50% of full rotational speed in the preset time (set by the Internal Timer),
the Controller will trip into Fail condition: refer to
for adjustment of the Internal Timer.
2. The following sections assume that you will connect the Controller to your control equipment and use
the control input signals on the logic interface connector to operate the pumping system.
When Start is selected, the Controller will switch on the electrical supply to the EXT pump and the pump rotor will
start to accelerate.
Use the following procedure to start up your system. This procedure assumes that you will manually operate the vent-
valve and the backing pump, however you can configure the Controller to automatically operate the vent-valve (refer
to
1. Close the vent-valve (if fitted).
2. Start the backing pump.
3. Start the EXT pump: close the Start/Stop input on the logic interface (see
).
4.2
Standby
To select Standby, close the Standby input on the logic interface (that is, ensure that the appropriate pins are linked:
see
).
If you select Standby when the pump is operating, the speed of the pump will be reduced to the Standby speed. If
you select Standby before you switch the pump on, the pump will run up to Standby speed, not up to full speed.
4.3
Operation with high inlet pressure
If the EXT pump inlet pressure rises, the power supplied by the Controller to the pump-motor will increase to
counteract the gas frictional load. The pump rotational speed will remain constant until the Controller peak power
level is reached; beyond this power level, the speed of the pump will start to reduce.
If the pump speed falls to below 50% of its full rotational speed, the Controller may trip into Fail condition; this
depends on how you have configured the Controller (see Sections
and
Refer to the EXT pump instruction manual for the maximum allowable inlet pressure, and refer to
for the
maximum Controller output power.
4.4
Operation with high pump temperature
Temperature sensors in the Controller and the EXT pump are monitored by the Controller. If the Controller detects
that the pump temperature is too high, the power supplied to the pump-motor is reduced; the pump may not
therefore be able to maintain full rotational speed if it is too hot.
If the pump speed falls to below 50% of its full rotational speed, the Controller may immediately trip into Fail
condition, or trip into Fail condition after a set time; this depends on how you have configured the Controller (see
Sections
and
Refer to the EXT pump instruction manual for the pump operating temperature ranges.