Functions
8.1 Soft starting
SIRIUS 3RW52 Soft Starter
Equipment Manual, 04/2020, A5E35630451002A/RS-AE/005
133
Parameters
Parameter
Description
Starting voltage
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 3RW52 soft starter.
x
Factory setting: 30%
x
Setting range: 30 ... 100%
Ramp up time
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 while the motor is starting up. A longer ramp up time results in a
shorter acceleration torque across the motor ramp up time. The motor
therefore runs up more slowly and smoothly.
Set the length of the ramp up time so that the motor can reach its rated
operating speed by the time the end of the ramp up 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 3RW52 soft starter can switch itself off
via the internal overload protection function and signal a fault.
With the setting "0 s", the motor is switched on with a ramp up time of
approx. 100 ms.
x
Factory setting: 10 s
x
Setting range: 0 ... 20 s
