| Electronics > Beginners |
| nobody talking about switching PS wasting power on input filter caps? |
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| Circlotron:
--- Quote from: radiolistener on August 24, 2019, 08:51:53 pm --- --- Quote from: Ice-Tea on August 24, 2019, 08:14:16 pm ---I'm not sure what you mean by 'consume', but if you mean that the generator gets the power back/consumes the power it delivered before then yes, that's what I've been saying all along. --- End quote --- Yes, I mean the power (which previously is delivered to the capacitor) is consumed back by AC source. So, we applied some amount of mechanical power to AC generator, it produce some amount of electrical power which is used to charge capacitor. Then capacitor applied this power back to AC generator and it was consumed by AC generator. So what happens to this power next? Does it affects mechanical rotation of AC generator? Or what happens with this power? Does this power just disappears? Does it slow down the rotor of AC generator? Does it speed up t he rotor of AC generator? ;) --- End quote --- I have never done the experiment, but I would expect that as the alternator is rotating and the capacitor voltage is increasing as energy is flowing into it, the alternator shaft gets harder to rotate. It is working as an alternator. Then later as the voltage is decreasing and the energy is flowing back to the alternator the alternator is operating like a motor and it would try to rotate ahead of whatever is driving it. It would actually return mechanical power to the gasoline engine flywheel or whatever. Think of it in familiar mechanical terms. Piston, connecting rod and crankshaft. For the first 90 degrees of crank rotation the piston mass is accelerated and it gains kinetic energy and it needs energy from the outside world to do this. Then in the next 90 degrees of rotation the piston is slowed down and while this is happening it returns the kinetic energy back to the crankshaft and whatever is connected to it. It tries to rotate the crankshaft faster than the crankshaft wants to go. The absolute fact that a connecting rod will stretch in a high speed race engine is proof of this chain of events. Physics being what it is, this comparison of electrical and mechanical is accurate enough for this discussion. |
| radiolistener:
--- Quote from: Circlotron on August 24, 2019, 10:15:18 pm ---Then later as the voltage is decreasing and the energy is flowing back to the alternator the alternator is operating like a motor and it would try to rotate ahead of whatever is driving it. It would actually return mechanical power to the gasoline engine flywheel or whatever. --- End quote --- why ahead? I'm inclined to believe that it will try to rotate back (to slow down). It's hard to believe that capacitor will keep AC alternator rotating for infinite time (with no heat loss). |
| soldar:
--- Quote from: radiolistener on August 24, 2019, 10:48:15 pm --- I'm inclined to believe that it will try to rotate back (to slow down). It's hard to believe that capacitor will keep AC alternator rotating for infinite time (with no heat loss). --- End quote --- You are inclined to believe wrong. You are being told by everybody. You are wrong. Science is not based on your inclination. Please stop being wrong. |
| radiolistener:
ok. I'm not familiar with AC alternators. May be that's true. So, if I understand correctly, capacitive load leads AC alternator to keep rotating. And inductive load leads to slow down. Is it correct? |
| Circlotron:
An inductor would have the same effect on an alternator. Ideally, a voltage source alternator with an inductor or a current source alternator with a capacitor, but that is complicating things even further. |
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