5. Evaluate your drive response.
– If the motor decelerates too slowly, then reduce the ramp-down time.
The minimum ramp-down time that makes sense depends on your particular application.
Depending on the Power Module used, for an excessively short ramp-down time, the
converter either reaches the motor current, or the DC link voltage in the converter
becomes too high.
– Extend the ramp-down time if the motor is braked too quickly or the converter goes into
a fault condition when braking.
6. Repeat steps 1 … 5 until the drive behavior meets the requirements of the machine or plant.
You have set the extended ramp-function generator.
❒
6.4.2.7 Dual ramp function
Overview
Submersible pumps suffer from insufficient cooling and lubrication when the pump speed is too
low. The initial ramp-up accelerates the pump to the minimum speed to reduce the wear and
tear. The long ramp time in the effective speed range improves the control accuracy for the
pump and fan. The ramp-down decelerates the pump from the minimum speed to stop and thus
reduces the shock to the valve.
Precondition
Before enabling the dual ramp function, make sure that p1138 = r29576 and p1139 = r29577.
Function description
Ramp up
● Converter starts ramp-up using ramp time from p1120 x p29570.
● When the actual speed r0063 > p29571, switch to ramp time from p1120 x p29572.
Ramp down
● Converter starts ramp-down using ramp time from p1121 x p29573.
● When the actual speed r0063 < p29574, switch to ramp time from p1121 x p29575.
Advanced commissioning
6.4 Setpoints and setpoint processing
SINAMICS G120XA converter
Operating Instructions, 03/2019, FW V1.0, A5E44751205B AB 245
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