How Does Electromagnetic Torque Develop in Rotating Electrical Machines?

[ranju]

Here , I want to clear about the cause of electromagnetic or interaction torque.>! I am confused in two things..
I read that the flux produced by stator coil & rotor coil interacts , the interaction give rise to electromagnetic torque..
But how this interaction produce torque..?? Is it like this- " the 2 flux (stator & rotor) generate 2 forces (couple) which tend to rotate the coil , which is the electromagnetic torque..??

And the second reason of electromagnetic torque I'hv read is .. the 2 flux rotor & stator flux produce their north & south poles individually..The stator S pole attracts rotor N pole & repels rotor S pole , resulting in clockwise torque.Similarly , stator N pole attracts rotor s pole & repels rotor N pole , resulting again in clockwise torque. The total torque developed is called electromagnetic torque.
Now are'nt these two different reasons..?? I am not able to relate the two , what actually is leading to electromagnetic torque..?? Please explain..

 

[milesyoung]

Here , I want to clear about the cause of electromagnetic or interaction torque.>! I am confused in two things..
I read that the flux produced by stator coil & rotor coil interacts , the interaction give rise to electromagnetic torque..
But how this interaction produce torque..?? Is it like this- " the 2 flux (stator & rotor) generate 2 forces (couple) which tend to rotate the coil , which is the electromagnetic torque..??

And the second reason of electromagnetic torque I'hv read is .. the 2 flux rotor & stator flux produce their north & south poles individually..The stator S pole attracts rotor N pole & repels rotor S pole , resulting in clockwise torque.Similarly , stator N pole attracts rotor s pole & repels rotor N pole , resulting again in clockwise torque. The total torque developed is called electromagnetic torque.
Now are'nt these two different reasons..?? I am not able to relate the two , what actually is leading to electromagnetic torque..?? Please explain..

When you read about electric machines, 'flux' is often synonymous with 'magnetic field lines', and is not to be confused with the scalar magnetic flux. Sometimes it's replaced by 'flux lines' to avoid the ambiguity.

A 'pole' is a way to describe a region of space where magnetic field lines either emerge from or enter, which, by convention, are given the names 'north' and 'south', respectively. Maybe you've seen an illustration like this:

So if you accept that the magnetic fields of the stator and rotor "will have a tendency to align", the descriptions you gave are really just one and the same.

 

[Ruben Crafts]

Even for me it was really very confusing to know between both things i.e electromagnetic or interaction torque. But Now milesyoung have explained it very nicely and with the help of this diagram with names 'north' and 'south', the concepts are more cleared. More similar information I have got here at http://www.airdexinc.com