Can we develop a permenant magnet induction motor on stator and rotor such that we obtain with little input power of 100 watts for example an output of 300 watts .
Depending on additional circuits controlling the magnetic behavior with coils and electric components .
Is it possible by theory to imagine 300 percent efficiency for a motor .
Any ideas of how to design controllable permenant magnet rotor stator with similar design of 3 phase induction motor?
No, it is impossible; it comes from the energy conservation law. It stems from this law, that it is impossible to produce more energy than You put in the imput for any device and by any physical proccess.
This problem was studied by philosophers and scientiscts starting many centuries ago, and was called in latin 'perpetum mobile' constuction.
With kind regrds, Piotr Wach, Opole, Poland
You cannot achieve even very close to 100%, forget about crossing the 100% limit. This is because of various losses in the motor.
When I was 11 years old I thought a good idea would be to have an electric motor turning a generator which would supply the motor with electricity and any spare electricity could be used to drive other device and do useful work.
I was quickly put in my place when told of the laws of conservation of energy and the fact that you can not get anything for nothing!
If you think about it, if what you suggest could be implemented, than all of our electrical energy problems would be solved.
But the simple fact is, all machines are less than 100% efficient. The list of losses for each process you look at, are known and well understood.
Ideally output=input. But prractically output=input-losses. So,we cannot achieve output more than 100%
Dear sir, Greetings! We are able to get efficiency more than 100% when we are able to convert losses in the machine for useful work. There are possible ways for wound rotor induction motor like Scherbius drive and Krammer drive, converting rotor copper loss to useful energy during speed control of Induction motor.
We have to work for such process for PM machines to my knowledge.
Regards.
If you could get more than 100% efficiency then you have created perpetual motion!
I understand that there are one or two universal laws stating this is impossible.
I think you should research perpetual motion as see what people say about this.
Dear E.V.C Sekhara Rao
- Even in doubly fed induction machines (known as slip energy recovery drives), there are still losses in the machine and the efficiency never exceeds 100%
- If you modify the definition, then efficiency can be more than 100%: define the efficiency of a synchronous generator as the ratio of "electrical power output" (from the armature) to "electrical power input " (to the field circuit). As you have taken here just the "electrical" powers and neglected the mechanical power, the electrical efficiency will be more than 100%. This can be interpreted as electrical power amplification, which of course is compatible with the energy (power) conservation principle.
I would consider it unwise to modify definitions of accepted quantities to achieve a notional step forward. Total electrical power out / Total mechanical power in, gives the efficiency value.
Dear Dr Steve Richards ,
Thanks for your response. I agree with you and I just wanted to give some hint to what is known as power amplification. If you have any other interpretation, I would be glad to have your view point.
Dear Mohammad Naser Hashemnia,
Thank you for your response. I am pleased you agree.
Power amplification!!
Yes of course we can swap more RPM for less torque etc but with no additional power.
I do feel that some people are looking for more than incremental increases in efficiency. But to suggest increasing "overall" efficiency to >100% will always send a red flag to me!
Dear Steve Richards ,
Thanks for your prompt response.
Then what is your idea about the terms "power amplifier" or "power amplification" which are commonly used in the electronic engineers literature?
Mohammad,
My views for what they are worth on 'power amplifier and 'power amplification' from the electronics engineers perspective is traditional:
An power amplifier for electrical or electronics purposes amplifies a signal, typically a voltage and increases its amplitude in terms of voltage, current or power. It is energised by an electrical power supply. We trade speed and accuracy against power efficiency.
Power amplification implies the multiplying the signal input power, say 1mW to 100W.
No more no less.
If you have additional information I would like to hear it.
Regards
Steve
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