4 replies to this topic

[Ambrose]

Dear All,

I am looking for a photo for real conection in a electrical panel, I am intereting for the way of connection of the resistors which connected to the aux. conactor.

Thanks in advance and have a nice day...

Ambrose

[Ambrose]

Dear All,

I am looking for a photo for real conection in a electrical panel, I am intereting for the way of connection of the resistors which connected to the aux. conactor.

Thanks in advance and have a nice day...

Ambrose

Dear All,

I am also looking for a formular for sizing of resisotrs of the aux. contactor.

Thanks in advance....

Ambrose

[marke]

Hello Ambrose

Ideally, the resistors should be sized so that the same current flows through the delta winding with the resistors in series as flowed through the windings in star.
i.e. the voltage drop acros the resistors should reduce the voltage across the windings to approximately line to neutral voltage.

Best regards,
Mark

[EngMhmd]

I have a question about star delta starter topic which posted in the website
For close transition mode

4-Closed Transition State. The Main [KM3] contactor is closed and the Delta [KM2] and Star [KM1] contactors are open. Current flows through the motor windings and the transition resistors ?????

The question is why we use the contactor and resistor if this contactor will close while srar and delta contactors are open is the same trouble as open transition mode becouse the star contactor and delta contactor are open ?? Is that clear

[marke]

No, The main contactor is closed connecting the beginnings of the windings to the supply and the secondary delta contactor with series resistors is closed connecting the ends of the windings to the supply via the resistors. This contactor is directly in parallel with the delta contactor, and closes before the star contactor opens.

At all times, the current flows through the windings.

 

Best regards,

Mark