Power in = Power outbut what about for solenoids?

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Discussion Overview

The discussion revolves around the efficiency and power dynamics of solenoids, particularly focusing on how different core materials affect their performance and power consumption. Participants explore the relationship between input power, output work, and energy losses in the system.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant posits that a solenoid operating at 12V DC and 1 amp consumes 12W, questioning how core materials influence its power efficiency.
  • Another participant explains that the efficiency of a solenoid in converting input power to useful work can vary, with losses due to resistive heating and mechanical friction.
  • A participant suggests that using iron as a core material improves power efficiency, although this is not universally agreed upon.
  • Concerns are raised about the concept of "wasted" power, with one participant arguing that power is only truly wasted when the plunger is not moving, while another counters that maintaining the plunger's position does not constitute useful work.
  • Further discussion highlights the distinction between electrical waste and mechanical utility, with some participants asserting that holding the plunger in place requires power, while others argue it could be done without power using mechanical means.

Areas of Agreement / Disagreement

Participants express differing views on what constitutes "wasted" power and the efficiency of solenoids with different core materials. There is no consensus on whether holding the plunger in place is a waste of power or a necessary function.

Contextual Notes

Participants reference the efficiency of solenoids in terms of energy conversion and the role of different core materials, but the discussion does not resolve the complexities of these interactions or the definitions of work and waste in this context.

Who May Find This Useful

This discussion may be of interest to those studying electrical engineering, physics, or mechanical systems, particularly in the context of solenoid applications and energy efficiency considerations.

infamous_Q
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Ok. so assume that you have a solenoid running about 12V DC and 1 amp. that's 12W. So that would suggest that this solenoid would have 12W of power when it performed tasks or needs to use that much power. But, different core materials make the solenoid more POWERful correct? (i may be misinterpreting this completely...) but how does it do this, and to what degree? (since power in = power out)
 
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It depends how efficient the solenoid is in converting the incoming power into something useful. A certain amount of the "power in" will be lost to electrically resistive loading for example, and dissipated as heat. Or the mechanics of the solenoid may use up the power by friction in the movement.

Different core materials have different reluctances which may effect how much power is needed to drive each type of material. For example it will take more power to persuade an air-cored solenoid to move than an iron-cored solenoid.
 
so then using iron as a core just technically makes it more power efficient?
 
pretty much
 
Power in = waisted power . . .
A solenoid does "usefull work" only during the fraction of a second when the plunger moves. Once the plunger stops moving - all the power you are supplying is turned into heat - waisted.

Oleh
 
Oleh Iwanusiw said:
Power in = waisted power . . .
A solenoid does "usefull work" only during the fraction of a second when the plunger moves. Once the plunger stops moving - all the power you are supplying is turned into heat - waisted.

Oleh
It may be "wasted" from an electrical point of view, from a mechanical view to keep the plunger/valve it is connected to in the desired position then that power is not really wasted.
 
FredGarvin said:
It may be "wasted" from an electrical point of view, from a mechanical view to keep the plunger/valve it is connected to in the desired position then that power is not really wasted.

a lot of people make this misconception. I can hold the plunger in place just as easily by running a pin through it to hold it in place and expend absolutely NO power whatsoever. The advantage is simply one of convenience. The power IS in fact wasted.
 
You can't always do that when the solenoid is unaccessible for whatever reason.
 
True, but the point still is that no actual work is being done.
 
  • #10
That is indeed true. I was looking at it from a broader sense, not the absolute definition. If I have a solenoid that is a power to open, so as to supply fuel to an engine that is doing work, can I really say that the power to hold the solenoid is being wasted? From the system involving the solenoid alone then I would say yes. It's just something I always get hung up on.
 

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