93 • Starting Procedure
________________________________________________________________________________________________
8.2.4 Choosing a Suitable Pump Curve (Centrifugal Pumps)
8.2.4
.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 (SOFT START CURVE 1!!).
• Set SOFT 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 the SOFT START CURVE setting to 2!!, or 3!!, if necessary. Each
increase in the SOFT START CURVE setting will reduce the peak torque, thus reducing the overpressure
and preventing “pressure surge” during start.
8.2.4.2 Stopping Curve
• Adjust MAIN PARAMETERS as necessary (FLA, FLC, etc.)
• Set SOFT 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 SOFT STOP CURVE 1!! and 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 “water hammer” persists, increase the time to 25 seconds
(confirm with motor manufacturer) and try again.
• If “water hammer” persists, increase the SOFT STOP CURVE setting to 2!!, or 3!!. Each increase in the
SOFT STOP CURVE will reduce the abrupt stop of the pump, thus preventing the “water hammer”
phenomenon.
To Next Page
Loading...
Need help?
General
