Soft Starter With Contactor Disconnector (Main Contactor) - Siemens 3RW44 Manual

Installation, connection and feeder configuration
4.2 Design of the feeder
4.2.4

Soft starter with contactor disconnector (main contactor)

If electrical isolation is specified, you can install a motor contactor between the soft starter
and the motor starter protector or you can use a fault output relay. (For contactor
assignments, refer to chapter Technical data (Page 253).
Figure 4-6
NOTICE
Error message due to delayed switching of the contactor
If a main or line contactor is connected between the soft starter and the motor or in the
return line between the motor and the soft starter, steps must be taken to ensure that this
contactor is connected within 100 ms of activation of the start command for the 3RW44.
If the contactor is not connected within 100 ms of activation of the start command for the
3RW44, the soft starter no longer recognizes the current circuit variant (standard circuit or
inside-delta circuit). A "Missing load phase 1-3" error message is generated.
38
Block diagram of a feeder with an optional main contactor / contactor disconnector
Manual, 03/2017, NEB535219502000/RS-AB/008
3RW44 soft starters