8.3.4 Choosing a suitable Pump Curve (centrifugal Pumps)
8.3.4.1 Starting Curve
Adjust MAIN PARAMETERS as necessary (FLA, FLC, etc..)
Set STARTING CURVE, ACCELERATION TIME, CURRENT LIMIT, and INITIAL VOLTAGE to
their default values (curve 0, 10 sec., 400% and 30% respectively).
Start the pump while watching the pressure gauge as the pump starts and look for overshooting
(“Pressure Surge”) of the gauge needle above the target pressure. In case of over pressure,
choose a peak torque reduction curve (Pump Control curve 1!).
Set START CURVE 1!, increase ACCELERATION TIME to 15 seconds and reduce CURRENT
LIMIT to 350%. Start the pump and watch the pressure gauge while the pump starts.
In most cases, overshooting is reduced. If the overshoot persists, increase ACCELERATION
TIME to 25 seconds (confirm with motor manufacturer) and try again.
If the overpressure persists, increase START CURVE setting to 2!, or 3!, if necessary. Each
increase in START CURVE setting will reduce the Peak Torque, thus, reducing the
overpressure and preventing the “Pressure Surge” during start.
To increase starting time above these maximums, employ “Special Starting” for these
techniques (Consult factory).