Dynamo design with regenerative back mmf

Click For Summary
SUMMARY

The discussion centers on a dynamo design utilizing regenerative back electromotive force (emf) to enhance rotor performance. It highlights the behavior of induced voltage across the coil during rotor movement, specifically at top dead center (TDC), where the switch closure allows current flow into the load. According to Lenz's Law, the induced current creates a magnetic field that opposes the rotor's motion, raising questions about its potential to propel rather than brake the flywheel. Participants emphasize the importance of understanding the principles of magneto ignition and the concept of E-Gap in this context.

PREREQUISITES
  • Understanding of Lenz's Law and its implications in electromagnetic systems
  • Familiarity with the concept of back electromotive force (emf)
  • Knowledge of magneto ignition systems and their operational principles
  • Basic principles of electromagnetic induction and changing magnetic flux
NEXT STEPS
  • Research the principles of magneto ignition and its applications in electrical systems
  • Study the concept of E-Gap and its significance in magnetic circuits
  • Explore advanced topics in electromagnetic induction, focusing on induced emf and current flow
  • Investigate practical applications of regenerative braking in dynamo systems
USEFUL FOR

Engineers, physicists, and hobbyists interested in electromagnetic systems, dynamo design, and regenerative energy technologies will benefit from this discussion.

Narayanan KR
Messages
76
Reaction score
4
disk rotor.jpg

In the above presented dynamo design, three snapshots taken during three instances during the rotor running.
In fig 1 the approaching magnet builds an induced voltage across the coil, however the circuit is still open, hence no current flows. In fig 2 when the rotor reaches TDC (top dead center) switch is closed leading to the flow of current into the load.
According to lenz law, this induced current flows so as to create north pole on the rotor facing side of the coil, and this will push the rotor away thus adding to the kinetic energy of the flywheel.
I wonder how the back mmf instead of braking the fly wheel, it pushes/propels the fly wheel, I hope you mates share your suggestions and critics on this idea, thank you.
 
Engineering news on Phys.org
Narayanan KR said:
View attachment 199294
In the above presented dynamo design, three snapshots taken during three instances during the rotor running.
In fig 1 the approaching magnet builds an induced voltage across the coil, however the circuit is still open, hence no current flows. In fig 2 when the rotor reaches TDC (top dead center) switch is closed leading to the flow of current into the load.
According to lenz law, this induced current flows so as to create north pole on the rotor facing side of the coil, and this will push the rotor away thus adding to the kinetic energy of the flywheel.
I wonder how the back mmf instead of braking the fly wheel, it pushes/propels the fly wheel, I hope you mates share your suggestions and critics on this idea, thank you.
Since no current flows in the coil while the switch is open, there is no storage of magnetic energy. Were you hoping that you found a viable Perpetual Motion Machine (PMM)?

Nice avatar, BTW. :smile:
 
  • Like
Likes cnh1995
berkeman said:
Since no current flows in the coil while the switch is open, there is no storage of magnetic energy. Were you hoping that you found a viable Perpetual Motion Machine (PMM)?

Nice avatar, BTW. :smile:
PMM?,I would never claim so. It was just a thought experiment performed within the rules of present physics and i was expecting an scientific explanation whether it works that way or not.
Even when coil is open it develops induced emf because of the changing magnetic flux linked to it, and the moment the load is connected across such emf current has to start flow.
 
Narayanan KR said:
PMM?,I would never claim so. It was just a thought experiment performed within the rules of present physics and i was expecting an scientific explanation whether it works that way or not.
Even when coil is open it develops induced emf because of the changing magnetic flux linked to it, and the moment the load is connected across such emf current has to start flow.
How does current flow through an open circuit? Mate in 2...
 
Narayanan KR said:
In fig 2 when the rotor reaches TDC (top dead center) switch is closed leading to the flow of current into the load.
At "TDC" the ##\Phi## is at a maximum so ##d\Phi/dt =0##. There is no EMF and no induced current.
 
  • Like
Likes cnh1995
@Narayan KR
You're approaching a 'magneto ignition'. Study up on that subject and you'll be better able to work your hypothetical machine in your head.

When you can explain its "E-Gap" in a couple concise sentences , please do. It'll both cement the concept in your mind and help other students of magnetics who stumble across this thread.

Did you make those nice drawings ?

old jim
 
Narayanan KR said:
PMM?,I would never claim so. It was just a thought experiment performed within the rules of present physics and i was expecting an scientific explanation whether it works that way or not.
Even when coil is open it develops induced emf because of the changing magnetic flux linked to it, and the moment the load is connected across such emf current has to start flow.

As Dale pointed out, there is no emf and no current at TDC. But as the magnet moves away from TDC, there will be an induced emf and current in the coil. The coil mmf should try to "oppose the cause" of the induction i.e. it should try to stop the magnet from going away.
So the coil should attract the magnet and reduce its kinetic energy.
 
  • Like
Likes jim hardy and berkeman
jim hardy said:
@Narayan KR
You're approaching a 'magneto ignition'. Study up on that subject and you'll be better able to work your hypothetical machine in your head.

When you can explain its "E-Gap" in a couple concise sentences , please do. It'll both cement the concept in your mind and help other students of magnetics who stumble across this thread.

Did you make those nice drawings ?

old jim
Yes sir..I did those drawings on MS Paint, and 'magneto ignition'...i believe it will be interesting.
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
5K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 7 ·
Replies
7
Views
7K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 5 ·
Replies
5
Views
4K