3
4.
SC10 Operation
Snore or Snooze Control. The SC10 Snore Controller monitors the electrical motor current via a 4-20mA output current
transformer (CT). By monitoring the centrifugal pump current the SC10 detects the low current when no or little fluid is being
discharged (called snoring) and stops the pump from running dry for extended periods. When low current is detected the unit
stops the pump. Note that Snore Control can work on both three-phase and single-phase motors.
The SC10 then pauses the pump operation for a time. The length of pause time before the next pump cycle is automatically
calculated. This pause time increases and decreases automatically to adjust to inflow based upon the time required for the last
pump run. The target duration of the pump run time is set via dip switches. The adaptive control algorithm will automatically
adjust the pump pause time to try to achieve the target run time.
Float Switch Support. The SC10 can operate the pump with no level sensors. Or, it can utilise external level (float) switches
either as the primary means of control or in combination with the snore control. Options Include:
Timer start, Snore stop
High level start, Snore stop
High Level start, Low Level stop
Push button start, Snore stop
Push button start, Low Level stop
Push button stop, Timer start
Push button stop, High level start
The start button will start the pump anytime that it is pushed and it will continue to run until the pump is again snoring or the
low level switch activates.
The SC10 also has a pump cleaning feature. The pump will stop periodically to allow a backflush as water runs back down the
discharge hose. This helps clear the impellor and the suction strainer of debris reducing the chance of blockage and cavitation,
as well as increasing the flow rate and efficiency.
Start-up of the SC10. The SC10 will normally start the pump 30 Seconds after start-up. The pump will run until a stop condition
is reach – snoring is detected or the stop/low float is activated. This pump start will not occur if the stop/low float is active.
4.1
Snoring Detection Explained
What is Snoring?
When the pump starts sucking air (called snoring) the pump flowrate and the pump current drop. This drop in current can be
detected by the SC10. This effect is shown in the graph below.
The Stop Current Setpoint
The Stop Current Setpoint is the current below which the
SC10 considers the pump to be snoring.
As shown in this graph, the pump runs at a Normal Running
Current until it begins snoring – indicated in the graph with
Pump starts snoring here. At this point the current drops to
a lower level.
If this lower Snoring Current is less than the Stop Current
Setpoint then the SC10 stops the pump.
What is the Current Window?
The normal way of setting the Stop Current Setpoint is to
press the Set button when the pump is snoring (see section
5.6). When the Set button is pressed, the Stop Current
Setpoint is set to the measured pump current plus the
Current Window. (Stop Current Setpoint = Measured Current
+ Current Window.) This is done so that the SC10 can reliably detect the snoring condition.
An Example
The operator is commissioning the pump which has a 0-100 Amp CT. They press Start. The pump runs normal at a current of 70%
(70 Amps), then the pump snores and the measured current drops to 50% (50 Amps). The operator hears the pump snoring and
presses the Set button combination.
If the Current Window DIP switches are set for a 10% current window then the Stop Current Setpoint is loaded with 60%.
