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View Full Version : Someone check me on this - 3-phase motor wiring.



Peter.
12-15-2011, 01:54 PM
This small 3-phase motor just has 6 leads coming from the casing - red,black and orange. I want to wire it in delta for VFD connection, which is easy just take any colour from the left and join it to any OTHER colour from the right, do this three times and you have delta.

What I am wondering is - does it matter at all what order they are connected in? red left to orange right, orange left to black right etc?

My gut feeling is that it doesn't matter but I can't reason why.

http://peterrimmer.myby.co.uk/images/3phase.jpg

Hopefuldave
12-15-2011, 03:26 PM
Sounds like you're on the right track - but buzz them out separately to make sure orange goes to orange as one winding, etc.

If it was originally star-connected, were all three joined on one side, that'd be a Clue as to which end of the winding is which. - the original would probably have the wires staggered by one position relative to the other side? If so, just link as though you were putting three straps across the terminal block.

Once you know which are ends of each winding, and assuming the star point was links all down one side, go (e.g.) Orange left to black right. black left to red right, red left to orange right, one VFD phase to each join.

If you get 'em the wrong way round, you'll have a motor spinning backwards :) If so, just swap 2 phases coming from the VFD and she's a good'un.

Dave H.

John Stevenson
12-15-2011, 04:18 PM
Yup, any other colour.

Peter.
12-15-2011, 04:45 PM
My concern was really about whether the order they need connecting must be the same as the order they are wound staggered on the stator. After thinking about it, red-black-orange is the just red-orange-black turning the other way.

The daft thing is I took the connector block off before machining the casing down but didn't think to mark the wires and note the arrangement :(

Cheers for the replies both!