Power in = Power outbut what about for solenoids?

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In summary, the power of a solenoid depends on its efficiency in converting incoming power into useful work. Different core materials can affect the amount of power needed to drive the solenoid, with iron cores being more efficient. However, once the plunger stops moving, all the power supplied is turned into heat and considered wasted. While some may argue that keeping the plunger in place serves a useful purpose, ultimately, no actual work is being done and the power can be considered wasted.
  • #1
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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  • #2
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.
 
  • #3
so then using iron as a core just technically makes it more power efficient?
 
  • #4
pretty much
 
  • #5
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
 
  • #6
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.
 
  • #7
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.

Alot 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.
 
  • #8
You can't always do that when the solenoid is unaccessible for whatever reason.
 
  • #9
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.
 

1. How does the principle of "power in = power out" apply to solenoids?

The principle of "power in = power out" applies to solenoids in the same way as any other electrical device. The power input into a solenoid is equal to the power output, taking into account any losses due to resistance or other factors.

2. What is the power source for a solenoid?

Solenoids typically require an electrical power source, such as a battery or power supply, to function. This power source provides the input power for the solenoid.

3. Can a solenoid generate its own power?

No, a solenoid cannot generate its own power. It requires an external power source to function.

4. How is power measured in a solenoid?

Power in a solenoid can be measured using a wattmeter, which measures the voltage and current in the circuit and calculates the power output. Alternatively, the power can be calculated using the formula P = VI, where P is power, V is voltage, and I is current.

5. Are there any factors that can affect the power output of a solenoid?

Yes, there are several factors that can affect the power output of a solenoid. These include the resistance of the solenoid wire, the quality of the power source, and any external forces or interference that may affect the solenoid's performance.

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