Starting several motors sequentially with a soft starter (cascaded control) [t-head2-col]

When starting several motors one after the other using a soft starter, keep to the following changeover sequence:

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Emergency-Stop

S1: Q11 Off

S2: Q11 On

Soft start/soft stop

Simulation of RUN relay
Timing relay K2T simulates the RUN signal of the DS4. The set off-delay time must be greater than the ramp time. To be on the safe side, use 15 s.

RUN

Off-time monitoring
Set the timing relay K1T so that the soft starter is not thermally overloaded: calculate the time from the soft starter’s permissible operating frequency or select a soft starter that allows the required time to be reached.

Changeover monitoring
Set the timing relay to a return time of about 2 s. This ensures that the next motor branch can not be connected as long as the soft starter is running.

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Switching off individual motors

The Off switch results in all motors being switched off at the same time. To switch off individual motors, you need to make use of N/C contact .

Observe the thermal load on the soft starter (starting frequency, current load). If motors are to be started at short intervals, you may have to select a soft starter with a higher load cycle.

Soft starters with motor cascade [t-head3-ls]

Soft starter with motor cascade, control section part 1 [t-head3-ls]

Soft starter with motor cascade, control section part 2 [t-head3-ls]