© Edwards Limited 2009. All rights reserved.
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Introduction
B800-00-880 Issue A
1.3
Pump controller
The pump controller contains the drive electronics that control the pump operation and the TAV vent valve. There
is a connector socket on the side of the controller where the TAV vent valve can be plugged-in. (Refer to
)
The controller has three indicator LEDs that signal the general status, operation and service status of the pump, that
can also be used for fault finding if a problem should occur. (Refer to
)
The drive electronics system has a number of built-in safety features to protect the nEXT pumps from damage in the
event of sustained high pressure or temperature:
The electronics constantly monitors the temperature inside the controller and the temperature of the motor
within the pump. If either part becomes too hot, the controller reduces the power supplied to the pump
motor and the pump speed will drop. If the pump rotational speed falls below 50% full speed, the electronics
may trip into a Fail condition, depending on how you have configured the system. (Refer to
).
If the nEXT pump's inlet pressure increases, the power supplied to the pump-motor increases to counteract
the gas frictional load. However, when the built-in maximum power limit is reached, the speed of the pump
will start to drop. If the pump rotational speed falls below 50% full speed, the electronics may trip into Fail
condition, depending on how the system has been configured. (Refer to
).
In the event of an electrical supply failure, the drive electronics uses the motor within the pump as a
generator. This means the nEXT pumps have their own regenerative supply and do not require a separate
battery for emergency power back-up. The regenerated energy is used to maintain the electrical supply to
the vent valve until the pump speed falls to below 50% of full rotational speed: this will ensure that the vent
valve remains shut until below 50% of full rotational speed and will prevent the pump from venting at full
speed.
1.4
Operational features
In addition to the basic start and stop commands, the nEXT pumps have several other features which allow you to
tailor the pump operation to your particular application. Refer to
Table 14
for factory default settings of the
parameters discussed in the following Sections.
1.4.1
Power limit setting
You can select the maximum power that will be drawn by the pump (refer to
). The more power you
supply, the quicker the pump will accelerate to reach full speed. Therefore if your application requires fast cycling,
you should set the power limit to the maximum value. If ramp time is not important in your application, you can use
a lower power limit, down to a minimum value, refer to
.
You must make sure that the power supply you use is capable of delivering sufficient power to the nEXT pump. By
choosing a lower power limit setting, you could use a smaller power supply. For more information, refer to
1.4.2
Standby speed
In Standby mode the pump rotational speed is lower than the full rotational speed. The default setting for standby
speed is 70% of full speed. Note that in order for standby speed to be selected, the pump must also be in the start
condition.
Table 1 - Power limits
Pump
Standard default setting
Maximum value
setting
Minimum value setting
nEXT240, nEXT300 & nEXT400
160 W
200 W
50 W
Содержание nEXT240
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