Parallel connection of several motors to a single soft starter [t-head2-pg]

You can also use soft starters to start several motors connected in parallel. This does not, however, allow the behaviour of the individual motors to be controlled. Each motor must be separately fitted with suitable overload protection.

Note 
The total current consumption of the connected motors must not exceed the soft starter’s rated operational current I_e.

Note
You must, however, protect each motor with thermistors and/or overload relays.

Caution!

Switching must not take place in the soft starter’s output as the resulting voltage peaks can damage the thyristors in the power section.

Problems may arise during starting if there are significant differences in the connected motors' ratings (e.g. 1.5 kW and 11 kW) which are connected in parallel to the output of a soft starter. The lower-rated motors may not be able to reach the required torque due to the relatively large ohmic resistance of these motors’ stators, requiring a higher voltage during starting.

It is advisable to use this circuit type only with motors of a similar rating.