SubDrive/MonoDrive Connect
Motor Soft Start
Normally, when there is a demand for water, the SubDrive/MonoDrive will be operating
to accurately maintain system pressure. Whenever the SubDrive/MonoDrive detects that
water is being used, the controller always "ramps up" the motor speed while gradually
increasing voltage, resulting in a cooler motor and lower start-up current compared to
conventional water systems. In those cases where the demand for water is small, the
system may cycle on and off at low speed. Due to the controller's soft-start feature and the
sensor's robust design, this will not harm the motor or the pressure sensor.
Power Factor Correction
Active Power Factor Correction (PFC) minimizes input RMS current by allowing the drive
to draw a cleaner, sinusoidal input current waveform. This allows for a reduction in input
power cable size when compared to similar applications without power factor correction,
because less average current is used by the drive for a given load when compared to non-
PFC devices.
Ground Fault Detection
The drive is equipped with Ground Fault Protection for the motor output. In the event that
a current leak to ground is detected on the motor output, the drive will indicate a Ground
Fault (Fault Code F16). See the Diagnostic Fault Codes table at the end of the instruction
manual for more information.
Adjustable Underload Sensitivity
The SubDrive/MonoDrive controller is configured at the factory to ensure detection of
Underload faults in a wide variety of pumping applications. In rare cases (as with certain
pumps in shallow wells) this trip level may result in nuisance faults. If the pump is installed
in a shallow well, activate the controller and observe system behavior. Once the controller
begins to regulate pressure, check operation at several flow rates to make sure the default
sensitivity does not induce nuisance Underload trips. See Basic Set-up section on page 28
for details regarding the Underload Potentiometer.
System Run Relay
The SubDrive/MonoDrive is fitted with a relay output that activates (normally-open contact
will close) whenever the system is actively pumping. Both normally-open (NO) and
normally-closed (NC) contacts are provided. The contacts are rated 5 A at 250 VAC/30 VDC
for general purpose loads, or 2A at 250 VAC/30 VDC for inductive loads (i.e. relay).
It is not recommended to use this function relay to control critical systems (chemical
dosing, etc.)
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