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Parameters
Parameter
Starting voltage
Ramp-up time
3RW51 Soft Starter
Manual, 06/2019, A5E37108631002A/RS-AB/002
Description
The starting voltage determines the starting torque of the motor. A lower
starting voltage results in a lower switch-on torque and a lower starting
current. Set the starting voltage to a value that ensures that the motor starts
up immediately and smoothly once the start command reaches the 3RW51
soft starter.
The ramp-up time determines the time taken to increase the motor voltage
from the parameterized starting voltage to the line voltage. This has an
influence on the motor's acceleration torque which drives the load during the
ramp-up operation. A longer ramp-up time results in a shorter acceleration
torque across the motor ramp-up. The motor therefore runs up more slowly
and smoothly.
Set the length of the ramp-up time such that the motor can reach its rated
speed by the time the end of the ramp is reached. The actual motor starting
time is load-dependent and can differ from the parameterized ramp-up time.
If you choose a time that is too short, the ramp-up time ends before the motor
has accelerated to speed. If the time selected is too short, a very high starting
current that equals the direct starting current at the same speed will occur. In
this case, the 3RW51 soft starter can switch itself off via the internal overload
protection function and signal fault.
If parameter value "0" is set, the motor is switched on with a ramp-up time of
100 ms approximately.
Functions
7.1 Soft starting
85
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