Functions
3.5 Motor control
M200D PROFIBUS/PROFINET
34 Manual, 08/2014, A5E01577426A/RS-AA/004
Control function soft starter
Description
Soft starters function according to the phase angle control principle. You can specify soft
starting and soft run-down using a settable voltage ramp. This function only applies to soft
starters.
The figure below illustrates the principle:
Figure 3-2 Soft starting/soft run-down principle
Termination of soft run-down (regenerative run-down)
Soft run-down is only meaningful if the motor does not run down regeneratively (moving
load). If soft run-down is nevertheless activated via parameterization, the motor starter
terminates soft run-down and switches the motor off. The brake output is switched off
depending on the set parameters.
Soft run-down on motor starters with mechanical braking
In parallel with soft run-down, motor starters with mechanical braking offer the following
control options with the parameter "brake holding time on stopping":
● Brake holding time on stopping = 0:
Motor voltage V is reduced to the stopping voltage during the run-down time. Following
this, the motor voltage and the brake output are switched off simultaneously.
When soft run-down is terminated, the motor voltage and the brake output are switched
off simultaneously.
● Brake holding time on stopping > 0:
Motor voltage V is reduced to the stopping voltage during the run-down time and
switched off. The holding time also runs in parallel with the run-down time. On expiry of
the holding time, the brake output is switched off independently of the soft run-down.
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