rsdoran
Lifetime Supporting Member
Sometimes I believe y'all overthink an issue, my problem is not knowing how to explain what I understand.
First thing I understand is that ANY MOTOR can also be a generator...ie if electric power is applied a motor will convert it to rotational energy...a generator uses rotational energy and converts it to electrical energy. I understand it gets a little more involved but basically this is a fact.
MY SIMPLE EXPLANATION:
A motor has 2 rotational aspects, the current
applied with AC creates a rotating magnetic field in the stator....for a 4 pole motor this "field" rotation equates to 1800 rpm....ie the poles will change "polarity" from North to South at this rate.
This magnetic field "induces" current into the rotor which in turn creates a magnetic field that is converted into rotational energy. This is where "slip" is involved. You only create electrical current when you pass a conductor through magnetic field lines of force. The stator has its magnetic field rotating within the motor housing at 1800 rpm, if the rotor were also rotating at 1800 rpm, the rotor conductors would not be passing through any magnetic field lines but rather moving with them. So, in order to generate a magnetic field in the rotor, the rotor must be moving slower than the stator magnetic field for the motor to produce mechanical power. Basically the rotor is being pushed/pulled around by the stators rotating field.
With that stated it should be understood that if a motor were running at synchronous speed there would be no magnetic lines being crossed so technically you would not produce any mechanical energy...this does not mean that there can not be rotation though but torque etc does have a proportional linear dropoff.
If you have "rotation" in a motor but the "rotor" starts rotating faster, over-haul or over-running condition, than the "stator" then the magnetic fields will be getting crossed in the opposite direction....ie now the rotor is inducing current into the stator. The rotor is no longer being pushed/pulled by the stator, the rotational energy, of the rotor, is now being converted into electrical energy that is greater that the electrical energy in the stator. Personally I do not believe this would be CEMF nor is it technically "internally generated".
I know this is all very simplistic but it helps(me)to understand. This is the basic principle behind regenerative drives.
I was going to use an analogy but they always create other questions.
First thing I understand is that ANY MOTOR can also be a generator...ie if electric power is applied a motor will convert it to rotational energy...a generator uses rotational energy and converts it to electrical energy. I understand it gets a little more involved but basically this is a fact.
MY SIMPLE EXPLANATION:
A motor has 2 rotational aspects, the current
applied with AC creates a rotating magnetic field in the stator....for a 4 pole motor this "field" rotation equates to 1800 rpm....ie the poles will change "polarity" from North to South at this rate.
This magnetic field "induces" current into the rotor which in turn creates a magnetic field that is converted into rotational energy. This is where "slip" is involved. You only create electrical current when you pass a conductor through magnetic field lines of force. The stator has its magnetic field rotating within the motor housing at 1800 rpm, if the rotor were also rotating at 1800 rpm, the rotor conductors would not be passing through any magnetic field lines but rather moving with them. So, in order to generate a magnetic field in the rotor, the rotor must be moving slower than the stator magnetic field for the motor to produce mechanical power. Basically the rotor is being pushed/pulled around by the stators rotating field.
With that stated it should be understood that if a motor were running at synchronous speed there would be no magnetic lines being crossed so technically you would not produce any mechanical energy...this does not mean that there can not be rotation though but torque etc does have a proportional linear dropoff.
If you have "rotation" in a motor but the "rotor" starts rotating faster, over-haul or over-running condition, than the "stator" then the magnetic fields will be getting crossed in the opposite direction....ie now the rotor is inducing current into the stator. The rotor is no longer being pushed/pulled by the stator, the rotational energy, of the rotor, is now being converted into electrical energy that is greater that the electrical energy in the stator. Personally I do not believe this would be CEMF nor is it technically "internally generated".
I know this is all very simplistic but it helps(me)to understand. This is the basic principle behind regenerative drives.
I was going to use an analogy but they always create other questions.
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