D396-20-880 Issue H
Page 2
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Introduction
1.2
Description
The EXC Controller generates the electrical supply and the control signals necessary to operate an EXT pump and its
accessories. Refer to
for compatible EXT pumps.
The Controller has a high-efficiency, auto-ranging power supply which adjusts itself to any external electrical supply
in the specified voltage range (refer to
). The power supply converts the single-phase electrical supply into
a regulated d.c. electrical supply to control the operation of the EXT pump. The pump has three Hall effect devices
which operate as rotor position sensors. These sensors ensure that the drive current is correctly switched to the
phase-windings of the pump-motor . The Hall effect devices also generate a speed signal which the Controller uses
to regulate the rotational speed of the pump.
The Controller has a secondary regenerative supply which uses the d.c. motor of the EXT pump as a generator. If the
electrical supply fails, the regenerative supply provides the Controller with a back-up source of power without the
need for batteries. The Controller uses the regenerative supply to maintain the electrical supplies to the vent-valve,
air-cooler and AIM gauge (if connected) until the pump speed falls to below 50% of full rotational speed (see
).
The Controllers have a number of control features which limit the power supplied to the EXT pump in the event of
sustained high pressure or temperature:
If the EXT pump inlet pressure rises, the power supplied to the pump-motor increases to counteract the gas
frictional load. The pump rotational speed remains constant until the Controller peak power level is reached;
beyond this power level, the speed of the pump starts 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
If the Controller detects that its temperature or the pump temperature is too high, it reduces the power
supplied to the pump-motor; 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 trip into Fail
condition; this depends on how you have configured the Controller (see
The Controller has no front-panel controls and can only be operated through the logic interface. To operate the EXT
pump, you must therefore connect the Controller to your own control equipment. Alternatively, you can configure
the mating-plug for the logic interface connector so that the EXT pump starts to operate as soon as the electrical
supply to the Controller is switched on: refer to
The rear-panel of the Controller has a Normal LED (
, item 6). The LED is on whenever the TMP Normal status
output signal is low: refer to
.
The EXC100L Controller has an integral pump-to-controller cable. The EXC100E Controller has a mating connector
suitable for a pump-to-controller cable accessory (not supplied): refer to
.
1.3
Connection of an Active Gauge
Note:
The Controller contains a regenerative power supply which maintains the electrical supply to the AIM gauge
in the event of a failure of the external electrical supply to the Controller (see
).
You can connect an Edwards AIM Active Inverted Magnetron Gauge directly to the active gauge connector on the
Controller and use the Controller TMP Normal signal to switch the gauge on. This allows you to control the AIM Gauge
without the need to use an additional high pressure gauge (and its associated control equipment) to interlock the
operation of the AIM Gauge to system pressure. Refer to
for details about how to connect an AIM gauge
to the Controller.
If you want to use another type of gauge, you must connect the gauge to the Controller through the logic interface:
refer to
