Body
Hi Kone,
By studying the four quadrants of the power circle it is easy to determine which way the energy works on a component. The power can be defined as either positive or negative when entering the component. When energy enters a component that component is a sink. If power entering the component is defined as positive that component is a sink in quadrants 1 and 3. The component is also said to be motoring. If power exiting the component is defined as positive the component is considered a source even though this is still quadrants 1 and 3 when using this second definition. The component is thus said to be generating. Which model to use depends on how the wires of the power meter (Watt meter) are connected. Switching around either the current leads or the voltage leads shifts between the two models. I.e. the opposite direction of energy flow (power) is defined as positive.
The first definition has sinks in quadrants 1 & 3 and sources in quadrants 2 & 4:
The source of this figure: https://www.researchgate.net/figure/Four-quadrants-operation-characteristics-of-a-DC-machine_fig3_324973158 https://www.researchgate.net/figure/Four-quadrants-operation-characteristics-of-a-DC-machine_fig3_324973158
The second definition has sinks in quadrants 2 & 4 and sources in quadrant 1 & 3:
The source of this figure: http://www.kepcopower.com/hdbfig09.htm http://www.kepcopower.com/hdbfig09.htm
With an oscilloscope with multiply function hooked up as a power meter and by using one of the above definitions it is easy to study the power entering and exiting a component. It can also be calculated by using mathematical models. If studying the capacitor and inductor (coil) this way it is easy to see what is going on and how both of these components are reactive components absorbing (sinking) and giving back (sourcing) energy. Using the same method on non-reactive components like lamps or resistors it will show only energy going into such components (sinks). A motor is also a generator when energy is exiting that motor. By experimenting with capacitors and inductors it can be shown that they are the exact opposites of each other which is why they start oscillating when connected together while storing energy.
Regards
Ole
---In [email protected], <konehead@...> wrote :
Hi Mick and Ole
Interesting!
Yes so cap is opposite to coil in current moves oin cap while voltage moves in coil....
Are the "functions of wben" also opposite?
Such as switch opening in coil creates backwards in direction voltages spike nstantly, while with a cap it s the switch closure that creates the "trying to be instamt" current flow as cap.fills up...
However, is there an amzlgous-to-flyback instantaneous current backflow "within" the cspacitor upon filling, or is this upon discharge, e both?
Could this be described as inherent back emf?
So maybe this analgous-to-flyback back current flow in cap will (also?)manifest during discharge to a load and the discharge switch closes?
I have been taught and told a cap fills up in one direction but discharges in opposite direction but this makes no sense in real life since you must hook pos to pos neg to neg when filling up and discharging cap to let's say battery both fills and another is load. Or to fill cap N with cap A you better habe pos on pos amd.neg on neg
Maybe this cap discharge of backward flow is that moment where a cap is filled to over-voltage level and it discharges on its own in explosive effect? I guess this discharge would be.imto the air more or less ..
Also I noticed that a cap into inductor discharge also follows the rule of pos.on pos neg to neg since if you want current flow same as it was with batteruy, you will need to hook cap up same polarity as bsttery...
So I don't know as usual just what works what doesn't but the opposite function and analogy of coil and flyback spike to cap and instant backwards current flow is very interesting
...maybe this is, or is confused with inherent back emf? I know half.thr world calls flyback spike back emf as a bit of confusion also maybe it is because what pushes that spike into "action" is the inherent back emf forces within the coil...the capacitance of the coil doing it so this source of confusion...now bring up TIME and when exactly things happen in each example, cap or coil and now is the.time function also ";opposite"?
Kone