240v 3 phase in 415v 3 phase motor

This almost certainly been asked before - Can I run 240v 3 Phase in 415 3 phase motor providing a halving in power is ok for the application?
Derek
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You can, but the normal technique would be to reconnect the motor from star to delta, which would then give you a 240V three phase motor. Most dual voltage motors will have a diagram in or on the terminal box (it will have 6 terminals if it is rewirable)
If the motor has been build permanent star, the star point can sometimes be found and separated so that the windings can be reconnected in delta.
Mark Rand RTFM
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Thanks Alas these motors are permanent star - Re butchering a permanent star to a delta Since delta uses more current would the windings necessarily take the extra current if I "hacked" it to a delta?
Derek
wrote:

star to

voltage
terminals
be
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The extra current comes because the windings are effectively in parallel rather than in series. Same current and voltage for the windings but SQRT 3 times the voltage and 1/SQRT 3 times the current for the whole motor.
Mark Rand RTFM
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wrote:

extra
of the 4 motors on the mill one is dual voltage already (suds) one I have a cheap replacement (vertical) , one is overspec and i'm not in rush for (horizontal arbour). The crucial one is the horizontal feed. for this I have found the star point and it "seems" straight forward to connect up as delta. Is there a way to get the physical orientation out of kilter with the electrical topology or will it all come out in the direction of rotation?
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dm wrote:

Not a problem. If the rotation direction is incorrect swap any two supply wires over.
Bob
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Quick rewind on that to avoid unnecessary release of magic smoke...
Mark the junction box ends of the windings A1,B1, C1
Using a meter, battery and bell, electric fencer and small child etc:- Mark the corresponding opposite (ex-starpoint) ends of the windings A2, B2, C2
Now connect A2-B1 B2-C1 C2-A1
If you accidentally connected a winding the wrong way round (say A2-B2, B1-C1) then the motor will draw a lot of current, generate little torque and get rather warm.
Mark Rand RTFM
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Mark Rand wrote:

Yes I agree. I had assumed that the Op would have done that check. _ Always dangerous to assume! Thanks for the addendum Mark. Bob
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