54 • STARTING PROCEDURE
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8.3.4.2 Stopping Curve
Adjust MAIN PARAMETERS as necessary (FLA, FLC, etc..)
Set STOP CURVE and DECELERATION TIME, to their default values (curve 0, 10 sec.,
respectively).
Stop the pump, watching the pressure gauge and check valve as the pump stops. Look for
overshooting (“Water Hammer”) of the gauge (abruptly stops the pump and the motor).
Select STOP CURVE 1, increase DECELERATION TIME to 15 seconds. Stop the pump and
watch the pressure gauge and the rate of closing of the check valve as the pump stops. Abrupt
stopping of the pump and motor will cause a loud audible noise emitted from the check valve.
In most cases, “Water Hammer” is reduced. If the “Water Hammer” persists, increase the time
to 25 seconds (confirm with motor manufacturer) and try again.
If the “Water Hammer” persists, increase STOP CURVE setting to 2!, or 3!. Each increase in
STOP CURVE will reduce the abrupt stop of the pump, thus, preventing the “Water Hammer”
phenomenon.
8.3.4.3 Final torque during soft-stopping a pump motor
While decelerating, the check valve may close before DECELERATION TIME has elapsed, thus, allowing
current to flow through stator winding causing unnecessary heat. Select FINAL TORQUE sensitivity to 1, and
stop the pump, confirm that current stopped flowing through the motor shortly after the check valve closed.
If current still flows more than 3-5 seconds after check valve closure, increase FINAL TORQUE up to 10 if
necessary, to stop current flow earlier
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