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4.2.2
Current measurement and ampere meter function
The control unit measures the current for each pump in a motor phase. The current is indicated in the
display. Additionally, the current is monitored and thus an electronic motor overload relay is simulated.
Undercurrent monitoring is also carried out.
4.2.3
Thermo contacts
As a general rule, waste water pumps feature one or two thermo contacts (Klixon) which trip at
different temperatures. If the first thermal contact trips, a fault situation is given and the pump is
stopped. In case the first thermo contact with the lowest temperature value trips, the pump will restart
up to ten times after the thermo contact has cooled down. The allowable number of restarts is
programmable. When the second thermal contact trips, this alarm is retained zero-voltage safe and it
must be reset (if required) before the pump is released again. (see Chapter 5.4).
4.2.4
Run time monitoring
Additionally, the control monitors the run time of the pump(s). If the max. adjusted run time of a pump
is exceeded, then an alarm is given. If 0 is set as max. run time value, then this function is
deactivated.
Note: Run time monitoring also takes place in case of high water.
4.2.5
Special characteristics when operating two pumps
When operating two pumps, two different operation modes are to be distinguished:
•
Alternating (or rotation) operation (1 / 1)
•
Peak load operation (2)
When operating the control with two pumps, the pumps will operate on a rotation basis, that is, the
pumps start alternatively so that, on an average, the load is evenly spread over the two pumps. In
case of peak load operation the second pump has an additional on and off switching level. If the
second cut-in level is exceeded or in case of high water, the second pump will additionally run as a
peak load pump. To avoid a possible overloading of the mains supply, the second pump performs a
delayed start according to the set delay time. In case of alternating operation, both pumps generally
will not run at the same time. If a pump has caused a fault or if it has manually been switched off, the
control unit will continue to work as a single pump control until the problem has been solved.
4.3
Fault messages and alarms
In addition to the above described fault messages assigned to the pumps, the control unit monitors
whether the following faults have occurred:
•
High water
•
Phase drop or phase sequence
•
faults in measuring technique (short circuit or wire breakage in the level sensor cable, inconsistent
float switch status
HSK_operating_manual_English_Ver3.doc
HOMA Pump Technology
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