Hello erkanozdemir,

there are some good comments regarding your request on the technical forum. Essentially the manuals are the best solution to find out the reason of some reactions.

Normally the softstarter 3RW40/3RW44 has the same internal logic to start the motor and switch to the internal baypass contactors.

The run-up detection is available at 3RW40 and 3RW44 works as follows:

1) The current must drop below the limit of 0.5 x starting current (3RW4 determines the starting current directly when switching on)

and

2) The current has to be <1.5 x In (In = set rated current)

If the switch on happens during a rotating motor, then the soft starter waits until the thyristors are fully controlled (normally after expiration of the set ramp time). Additionally the current has to be constant for 2s (and of course smaller than the respecting rated current of soft starter).

If the softstarter switch off without any error message it could be that the start command is off (or lost) or the control voltage was going down.
regards