Recently I saw some machines supplied from Chinese company in textile plants. They have used Micromaster of different frame sizes. All the DC link terminals are connected to a common bus.

Thank you very much for your reply;

do you have any engineering details for such application?

Here they had two schemes

1. Micro masters of frame size A to F are used with a common DC.

Application is something like conveyor and as you said drives are in Motoring/ Generating modes.

1. They have another scheme where one 110kw Micromaster and another 55KW micromaster were put on DC bus . Once the drives starts running they switched off input supply for 55KW drive. And the Dc bus of 110Kw runs both the drives.

Both the drives are used only up to their 50% capacity..

Now when we put Micro masters (Below frame size F ) on such bus there won’t be any protection to their internal Rectifiers .( All units are having simple diode rectifier ).

In case of failure of a single inverter will cause damage to another drive ( rectifier sections.)

Similarly what could be the motto behind second scheme. Unfortunately for second scheme motors are used as stand alone.