What governing factors determine how loads are powered?

[doubleenigma]

Hi,

I was wondering, what are the governing factors that control how loads are powered by circuits? If a 300hp motor is connected to Source A, Source A will supply 300hp of power at whatever the specified voltage is. But at the atomic/subatomic level, what really determines how that power is "shipped" to the motor?

 

[haxor489]

It isn't power that is being shipped it is the forced motion of electrons being manipulated to do something useful.

The governing factors are: voltage(V), current(I) and resistance(R).

Source A has a voltage potential. Once connected to said motor, which has a certain amount of resistance it will permit a certain amount of current to flow through. Specifically V/R = I ( ohms law ). It's the current ( flow of electrons) as a result of potential difference on a conductive wire that allows that "power to be shipped". I hope i understood your question correctly

 

[doubleenigma]

Yes, I'm aware of Ohm's Law. I understand that at the endpoint (or, the load) the energy held in the charged electrons will mostly be converted to do useful work, while some will be converted into photons which are felt as heat.

I think I may be struggling to determine what it is that I want to ask, but I feel that it's the starting point that gets me confused. Why does a power source -- be it a battery, a solar panel, or a generator -- decide to output 300hp of power to a 300hp motor? Why not deliver 250hp to a 300hp motor? Yes, Ohm's Law does play a role in this, but there must be a deeper answer than simply that. How does the source see the load and know exactly what amount of energy is needed to perform the task required of the load?

 

[haxor489]

I don't know what power source you're referring to that can do such a thing. A battery for instance does not determine anything, it provides a potential difference. Let's say for instance we have a 300 hp motor with a resistance of R, just because i hook it up to an electric power source doesn't mean it will dissipate 300 hp. Horse power is related to wattage by 1 hp = 746 watts. Electric power in wattage is calculated by voltage*current. So if i wanted to know what potential to run across this motor to achieve its 300 hp rating :

746*300 gives us its power consumption of 223800 watts
223800/R = would tell us the voltage required run the motor with 300 hp.

I think you're using the terms energy and power a little too loosely. In physics and electrical engineering they are related but are not one and the same.

 

[alphysicist]

I can tell you that the governing factors that determine how loads are powered are primarily related to the fundamental principles of electromagnetism and energy conservation. At the atomic/subatomic level, the flow of electric charge through a circuit is controlled by the movement of electrons, which are negatively charged particles. This movement is facilitated by the voltage difference between the two ends of the circuit, which creates an electric field that pushes the electrons along.

In addition to voltage, the resistance of the circuit also plays a crucial role in determining how much power is delivered to the load. Resistance is a measure of how difficult it is for electrons to flow through a material, and it can be influenced by factors such as the type of material, its temperature, and its dimensions. A higher resistance will result in a lower flow of electrons and therefore less power being delivered to the load.

Furthermore, the type of power source being used will also impact how loads are powered. For example, a direct current (DC) source, such as a battery, will deliver a constant flow of electrons in one direction, while an alternating current (AC) source, such as a power grid, will periodically reverse the direction of electron flow. This difference in current type can affect the efficiency and performance of the load being powered.

Overall, the governing factors that determine how loads are powered involve a complex interplay between voltage, resistance, and current flow, as well as the properties of the power source and the load itself. Understanding these factors is crucial for designing efficient and effective circuits that can power a wide range of loads.