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Time
Illustration 30: Example of Current Ramp Soft Starting
1
Parameter 2-3 Initial Current
2
Parameter 2-2 Start Ramp Time
3
Parameter 2-4 Current Limit
4
Full voltage current
9.8.3 Constant Current with Kickstart
Kickstart provides a short boost of extra torque at the beginning of a start, and can be used with current ramp or constant current
starting.
Kickstart can be useful to help start loads that require high breakaway torque but then accelerate easily (for example helical rotor
pumps).
700
600
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Rotor speed (% full speed)
Illustration 31: Example of Kickstart used with Constant Current
1
Parameter 2-7 Kickstart Level
2
Parameter 2-6 Kickstart Time
3
Parameter 2-3 Initial Current
4
Parameter 2-2 Start Ramp Time
5
Parameter 2-4 Current Limit
6
Full voltage current
9.8.4 Timed Voltage Ramp
Timed voltage ramp (TVR) soft starting ramps the application of voltage to the motor over a defined time period. The voltage ramp
reduces the initial starting torque and slows the motor's rate of acceleration.
TVR starting can be useful for applications where multiple motors of different sizes are connected in parallel, and/or the loads are
not mechanically linked.
AQ262141844215en-000401 / 175R1174
64 | Danfoss A/S © 2020.12
Operation
VLT® Soft Starter MCD 600
Operating Guide