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Introduction
B722-40-880 Issue H
The electronics constantly monitor the temperature inside the Podule and the temperature of the motor
within the pump. If either part becomes too hot, the electronics reduce 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 Fail condition, depending on the system configuration. (Refer to
If the pump 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 the system configuration. (Refer to
In the event of an electrical supply failure, the drive electronics use the motor within the pump as a
generator. This means the DX pumps have their own regenerative supply and do not require a separate
battery for emergency power backup. The regenerated energy is used to maintain the electrical supply to
the connector socket on the Podule 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, provided that there is not too much loading on the 24 V supply to the pump.
1.4
Operational features
In addition to the basic start and stop commands, the DX pumps have several other features for improved
functionality. These allow pump operation to be tailored to the particular application. Refer to
for factory
default settings of the parameters discussed in the following Sections.
1.4.1
Power limit setting
Select the maximum power that will be drawn by the pump (refer to
). The more power supplied, the
quicker the pump will accelerate to reach full speed. If the application requires fast cycling, set the power limit to
the maximum value. If ramp time is not important in the application, use a lower power limit, down to a minimum
value, refer to
Ensure that the power supply is capable of delivering sufficient power to the DX pump. By choosing a lower power
limit setting, a smaller power supply can be used. For more information, refer to
.
1.4.2
Standby speed
In Standby mode the pump rotational speed is lower than the full rotational speed.
If the application does not require the pump to be running at maximum speed at all times, use the Standby speed
feature rather than switching the pump off. This can save time since the pump does not have to be stopped or vented
and the wait time for the pump to accelerate back to full speed will be reduced.
The Standby speed is a user-selectable value (refer to
).
1.4.3
Timer
When the pump is started, an internal timer is automatically started within the drive electronics. If the pump fails
to reach 50% of full rotational speed within the time-out period, the Podule will signal a Fail and will decelerate the
pump to rest. This is a safety feature and prevents the Podule driving the pump at maximum power for a long time,
which could cause damage. The pump may fail to reach 50% speed if the gas load is too high (for example if there is
a leak in the system), if the backing pump fails, or if the pump is too hot.
The time-out period is a user-selectable feature (refer to
). If the application requires the pump to ramp
up slowly, extend the time-out period. The Timer is permanently enabled for ramp-up.
Table 1 - Power limits
Pump
Maximum value setting
Minimum value setting
EXT75DX
120 W
50 W
