BEMF MAGNO MOTOR

[DMMPOWER]

hi have a look at this !

[gyulasun]

Hi DMMPOWER,

It is good you have returned    and show us an interesting setup.

I think when you place a capacitor across the AC input connectors and you make the two coils + the capacitor to be resonant at the incoming AC frequency, you could reduce the input power consumption.  Agree?
Do you use brushes to feed the rotor coil(s)?

Would you mind also returning to your earlier topic here http://www.overunity.com/index.php?topic=4715.0  and continue with Stage 2 and so on, please?   

Many Thanks,
Gyula

[DMMPOWER]

In the coil in a motor due to Lenz’s law the supplied emf is resisted or opposed by induced emf or back emf.





emf is voltage. In a motor as you have a changing magnetic field relative to a current carrying conductor, due to Lenz’s law a back emf will be generated to oppose this changing magnetic field. As it will oppose a back emf will be generated.


If no back emf was present in a motor, then the motor will just keep getting faster and faster, this opposes the law of conservation of energy, and so thus an opposing emf, a back emf is produced.


The net emf equals the supplied emf minus the back emf,




net emf = supplied emf âˆ' back emf

In an ideal motor with no friction the motor will speed up until it has enough speed so that the generated back emf equals the supplied emf. At this point the net emf is zero and so as there is no current in the coil there are no forces acting on the coil. Now remembering that this is an ideal motor with no friction, if there is no force then the coil will just keep spinning at constant speed.


When the motion of the coil is resited, say by a load, then the coil will be spinning slower and so the back emf (which is induced due to the relative motion of a coil and a magnetic field) will be less. As the supplied emf is constant and as the back emf is less, the net emf will not be zero. It will be greater than zero. It is this non-zero net emf that allows for extra force (the greater the current then the greater the force ie. motor effect) to push against the load. If the load is too great then the motor slows and less back emf is generated and the net emf is too high. If this happens, the motor can overheat because the current is too high.

[Liberty]

In the coil in a motor due to Lenz’s law the supplied emf is resisted or opposed by induced emf or back emf.





emf is voltage. In a motor as you have a changing magnetic field relative to a current carrying conductor, due to Lenz’s law a back emf will be generated to oppose this changing magnetic field. As it will oppose a back emf will be generated.


If no back emf was present in a motor, then the motor will just keep getting faster and faster, this opposes the law of conservation of energy, and so thus an opposing emf, a back emf is produced.


The net emf equals the supplied emf minus the back emf,




net emf = supplied emf âˆ' back emf

In an ideal motor with no friction the motor will speed up until it has enough speed so that the generated back emf equals the supplied emf. At this point the net emf is zero and so as there is no current in the coil there are no forces acting on the coil. Now remembering that this is an ideal motor with no friction, if there is no force then the coil will just keep spinning at constant speed.


When the motion of the coil is resited, say by a load, then the coil will be spinning slower and so the back emf (which is induced due to the relative motion of a coil and a magnetic field) will be less. As the supplied emf is constant and as the back emf is less, the net emf will not be zero. It will be greater than zero. It is this non-zero net emf that allows for extra force (the greater the current then the greater the force ie. motor effect) to push against the load. If the load is too great then the motor slows and less back emf is generated and the net emf is too high. If this happens, the motor can overheat because the current is too high.

If no back emf was present in a motor, then the motor will just keep getting faster and faster, this opposes the law of conservation of energy, and so thus an opposing emf, a back emf is produced.

What I have found, is that as long as you use a coil in a motor, the coil simply works as a generator whenever exposed to a magnetic field that changes, (which happens a lot in motors with coils) and power generation opposes your use of a coil as a motor that is fed with power input.  It has little to do with the law of conservation of energy.  It is just a coil subjected to a changing magnetic field will act as a generator, opposing the function of a motor.  The answer:  Don't use coils unless you want to generate electricity.

[DMMPOWER]

Yes what I have found, is when you use a permanent magnet  with a moving coil you always produce emf.

But  when you use two coil that oppose one other with the same oscillating magnetic force they will cancel each other's  BEMF.