What is doing the work in the motor effect?

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Discussion Overview

The discussion centers around the mechanisms involved in the motor effect, specifically what does the work in producing the force exerted on the armature of a motor. Participants explore the roles of electric and magnetic fields, energy transfer, and the sources of energy in this context.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants suggest that the interaction between the magnetic field produced by the current and the magnetic field in which the armature moves causes the armature to spin.
  • Others propose that the electrons moving through the wire are attempting to reach a lower energy state, thus performing the work.
  • One participant argues that the work is done at the power plant, where electrons are pushed through the circuit.
  • A participant questions the nature of work done in the conversion of electrical energy to mechanical energy, suggesting that some work must occur in this process.
  • Another participant uses an analogy of a water wheel to illustrate how flowing electrons, similar to flowing water, cause mechanical movement through electromagnetic forces.
  • One summary states that the power plant creates electric potential energy, which is converted into mechanical energy by the interaction of electrons and magnetic fields, but invites scrutiny on the precision of this explanation.
  • A later reply points out that the efficiency of motors can vary, with losses attributed to factors like winding resistance and friction.
  • Some participants challenge the reasoning that traces energy back to the power plant, suggesting that this could lead to an infinite regress and advocating for a more straightforward attribution of work to the fields involved.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the source of work in the motor effect, with no consensus reached on a singular explanation. The discussion remains unresolved with various interpretations and analogies presented.

Contextual Notes

Participants highlight the complexity of defining energy sources and the nature of work done in the motor effect, indicating that assumptions about energy transfer and efficiency may vary based on context.

infomike
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When electrons move through an armature, the magnetic field produced by the current interacts with the magnetic field it's moving through. This interaction causes a repulsion which produces the spinning of the armature in a motor.

Would someone please explain what is doing the work in producing the force that is exerted on the armature? Magnetic field? Electric field?
 
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The electrons traveling thru the wire are attempting to move to a lower energy state and thus are doing the work.
 
The work is done back at the power plant, pushing the electrons through the circuit.
 
There must be something more to this. If electrical energy is transferred to mechanical energy as in the motor effect, wouldn't some work have to be done in this process?
 
infomike said:
There must be something more to this. If electrical energy is transferred to mechanical energy as in the motor effect, wouldn't some work have to be done in this process?

Perhaps If you think of it in terms of a stream and a water wheel. What is causing the water wheel to turn? The water, right. Why? Because the water is flowing from a higher potential to a lower potential and pushes the water wheel causing it to rotate. The electrons are doing the same thing only it involved electromagnetic forces.

If you reversed the process and used the motor as a generator then it would push the electrons back to the battery doing work to raise the electrons potential.
 
Okay...so from what I read here and other places, I will summarize:

1. Power plant supplies the work creating the electric potential energy.
2. Current flows into motor, which is electric kinetic energy.
3. Electrons flowing through a magnetic field cause a magnetic field interaction which converts the potential energy of the fields into the mechanical energy of the armature. Work is being done here also.

Sound right to everyone?
 
infomike said:
Okay...so from what I read here and other places, I will summarize:

1. Power plant supplies the work creating the electric potential energy.
2. Current flows into motor, which is electric kinetic energy.
3. Electrons flowing through a magnetic field cause a magnetic field interaction which converts the potential energy of the fields into the mechanical energy of the armature. Work is being done here also.

Sound right to everyone?

Yes, but if you want to get picky, #1 is problematic in that you could go back to the water in a hydroelectric dam that creates the power from gravity. In other words, depending on how precise you want to be, you have to say what ACTUALLY supplies the power IN the power plant.
 
An ideal motor would be 100% efficient. All the energy going in would be converted to mechanical energy. You can buy brushless motors that are >95% efficient.

The remaining losses are typically due to the residual winding resistance, eddy currents, bearing friction and air drag on the rotor.
 
phinds said:
Yes, but if you want to get picky, #1 is problematic in that you could go back to the water in a hydroelectric dam that creates the power from gravity. In other words, depending on how precise you want to be, you have to say what ACTUALLY supplies the power IN the power plant.

Why does it have to be at the power plant? This type of reasoning will lead you back to the formation of the sun and the universe... IMO this is no way to answer the question. When we say that a rock gains energy as it falls we say that the gravitational field does the work on the rock, because it is that which is supplying the force along the direction. We do not say that the seismic event that raised the rock up there millions of years ago did the work.
 
  • #10
ModusPwnd said:
Why does it have to be at the power plant? This type of reasoning will lead you back to the formation of the sun and the universe... IMO this is no way to answer the question. When we say that a rock gains energy as it falls we say that the gravitational field does the work on the rock, because it is that which is supplying the force along the direction. We do not say that the seismic event that raised the rock up there millions of years ago did the work.

Yes. It just gets to a 'chicken and egg' argument with. possibly, the Big Bang at the start of it all. You are always allowed to have a black box somewhere with "Energy Source" written on it.
 

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