2 speed motor 3 phase 380 volt motor

[bergie]

looks correct,although i'm not sure why the overload contacts are on the star point

[5barware]

looks correct,although i'm not sure why the overload contacts are on the star point

It should be on the star point. It is a 3 phase motor. Each winding powers on independently. If the overload protector is just on one winding, when overload happens, the protector just can cut off one winding power. The other two windings still power on. Then the motor can still run. So the protector must be on the star point, when overload happens, the protector can cut off all the windings power once.

[bergie]

an overload relay just switches the contactor off and all windings have no power. the star point of a motor can be connected to neutral,but doesnt need to be

[mikilianis]

Hi a quick sketch of how it should be wired up I did the power circuit and the control circuit Two Speed Motor Circuit.pdf

[5barware]

an overload relay just switches the contactor off and all windings have no power. the star point of a motor can be connected to neutral,but doesnt need to be

I can not understand what you want. And what is the problem? I think it is ok design like this.

[bergie]

thanks mikilanis your drawing looks perfect . 2 overload relays. 5barware sorry but the 2 overload current contacts just makes no sense. what is it for? the rest of the drawing looks good.

[mikilianis]

The contact on the overload unit, usually identified by the numbers 95 and 96 is a normally closed contact( which open when the overload unit opens the circuit due to excessive current drawn by the motord ) and is used in the control circuit in series with the stop, when the contact opens the contactor is de-energised

[bergie]

http://www.theforumsa.co.za/forums/a...4&d=1395062004

mikilianis, i actually meant 5barware's drawing of the overload contacts.he has drawn it connected it to the star point,which doesnt make sense.

[mikilianis]

Hi bergie apolagies maybe 5barware is useing the star point as neutral and energising the coils from a live to the star point I do not know maybe it is the chinese way of wireing up a cotactor strange I must admit.