Electronics > Beginners
nobody talking about switching PS wasting power on input filter caps?
radiolistener:
--- Quote from: Zero999 on August 24, 2019, 05:40:19 pm ---Note, that average power taken from V1 is zero, over the entire waveform.
--- End quote ---
Yes. And my explanation is that this energy is consumed by AC source and it makes rotation of AC generator more hard. You're needs to apply more mechanical energy to keep AC voltage.
But Ice-Tea, soldar and james_s claiming that this energy is not consumed by AC source and it doesn't change load resistance for AC source. So technically they claimed that there is perpetuum mobile or some kind of free energy :)
So who is right?
Zero999:
--- Quote from: radiolistener on August 24, 2019, 05:58:16 pm ---
--- Quote from: Zero999 on August 24, 2019, 05:40:19 pm ---Note, that average power taken from V1 is zero, over the entire waveform.
--- End quote ---
Yes. And my explanation is that this energy is consumed by AC source and it makes rotation more hard. You're needs to apply more mechanical energy to keep AC voltage.
--- End quote ---
If the power is zero, then why would more mechanical energy be required?
--- Quote ---But Ice-Tea, soldar and james_s claiming that this energy is not consumed by AC source and it doesn't change load resistance for AC source. So technically they claimed that there is perpetuum mobile or some kind of free energy :)
So who is right?
--- End quote ---
You're wrong.
No, they're not claiming free energy.
--- Quote ---What happens with power consumed by AC source?
I provided you with answer - this power will be used against AC generator. In simple words this power will be used to stop rotation of AC generator rotor. In order to continue AC generating you're needs to apply more mechanical power to AC generator.
This is my explanation. So, what is your explanation, what is happens with power consumed by AC source?
--- End quote ---
There's a clear gap in your understanding. You haven't considered the fact that the alternator can also work as a motor. Take energy out of it and put it into the capacitor and it will increase the load on the engine. Put energy back into it, from the capacitor and it will reduce the load on the engine. The mechanical inertia will smooth this out so it will behave as if there's no mechanical load.
soldar:
--- Quote from: radiolistener on August 24, 2019, 05:58:16 pm ---Yes. And my explanation is that this energy is consumed by AC source and it makes rotation of AC generator more hard. You're needs to apply more mechanical energy to keep AC voltage.
--- End quote ---
This is wrong.
Photo of capacitors in substation:
https://en.wikipedia.org/wiki/File:Condensor_bank_150kV_-_75MVAR.jpg
They don't put them there so they can waste energy.
radiolistener:
--- Quote from: Zero999 on August 24, 2019, 06:12:54 pm ---If the power is zero, then why would more mechanical energy be required?
--- End quote ---
Because energy generated with AC generator rotation was accumulated by capactior and then returned back to AC generator. AC generator consumed returned energy to make rotor rotation more hard.
So, if you don't apply more energy, rotor will slow down and stop and AC voltage will drops down to zero. In order to keep AC voltage at 311 Vpk 50 Hz, you're needs to apply more power.
--- Quote from: Zero999 on August 24, 2019, 06:12:54 pm ---
There's a clear gap in your understanding. You haven't considered the fact that the alternator can also work as a motor.
--- End quote ---
I considered that. But it can works as a motor if you feed it with in-phase AC. Which is not the case for capacitor. Capacitor feeds AC generator with phase shifted AC.
If AC generator rotating clock wise, the capacitor will feed AC generator in such way so it will rotate counter clock wise.
Just look, if it works like you say, it will turns into perpetuum mobile, which is not possible. It doesn’t bother you?
radiolistener:
--- Quote from: soldar on August 24, 2019, 06:20:44 pm ---This is wrong.
Photo of capacitors in substation:
https://en.wikipedia.org/wiki/File:Condensor_bank_150kV_-_75MVAR.jpg
They don't put them there so they can waste energy.
--- End quote ---
They needs to remove reactive component from the load impedance. If load already don't have reactive component, they don't needs and don't used.
Do you know that load may have reactive component in it's impedance?
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