78 • Control Keypad
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7.7.4.1 Soft Stop Parameters
The RVS-DN incorporates 5 stopping curves that enable you to select the suitable torque curve
Stop Curve 0 – Standard Curve (Default) – voltage is linearly reduced from nominal to zero.
The most stable and suitable curve for preventing prolonged stopping and motor overheating.
Stop Curves 1, 2, 3 Pump Control
– In some pump applications, when pumping to higher elevation a
considerable part of the torque is constant and does not decrease with speed.
It may happen that during the deceleration process when voltage decreases the motor torque abruptly falls
below load torque (instead of smoothly decreasing speed to zero), thus closing the valve and causing water
hammer.
Curves 1, 2 and 3 eliminate the water hammer phenomenon. In pump applications the load torque decreases
in square relation to the speed, thus correcting control of voltage to reduce torque adequately and to smooth
deceleration to a stop.
Note
:
It is recommended that STOP CURVE 0 be used for all standard applications (not pumps).
To reduce water hammer, select STOP CURVE 1, then 2, then 3 in that order.
Curve 4 - Torque Curve
- Provides linear deceleration of the torque. In certain loads, linear torque
deceleration can result in close to linear speed deceleration, thus eliminating stall conditions.
Note:
Always use STOP CURVE 0. If the motor stalls quickly instead of slowly decreasing its speed, select STOP
CURVE 1, 2, 3 or 4 in that order until the problem is solved.
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