Anyone Build a Power Regenerator?

[grataku]

Originally posted by Peter Daniel
That's the way this digital scope shows the waves. I never seen it here like on a regular scope. You've seen same wave with 50V and 10mV scale.

I'll take a look tonite, I'll have to grab a variable attenuator on my way home.
How do you measure 120VAC? I am afraid I'll fry something...

[Da5id4Vz]

WHats that smell...

Urine!

Ive jumped into yet another DIY ****ing match.

I'm outa here before my otes get wet.

Ciao!

http://millinfo.org/upsfire/

[grataku]

Originally posted by Da5id4Vz
WHats that smell...

Urine!

Ive jumped into yet another DIY ****ing match.

I'm outa here before my otes get wet.

Ciao!

http://millinfo.org/upsfire/

I would stick around if I were you. Some good may still come from this thread. I don't like to propagate flames anymore, but I needed to say something.

[fdegrove]

Hi,

It is not switchable, so it seems like the unit regenerates power all the time, no matter if AC or battery operated.

That's quite likely the case.

All the UPSs I've seen from APC do that as well...there's probably little point in switch it on/off anyway.

Cheers,

[ALW]

The distortion for my oscillator was over 80 dB down and the amplitude was much more stable than my AC line voltage at the wall

The issue here Fred, as Martin alludes to, is the step-up transformer raises o/p Z.

Add a highly non-linear load (rectified DC supply) and all the low distortion performance in the oscillator goes out the window, as bad, if not worse, as the conventional mains.

You can add feedback at LF around the transformer, but can't really extend this beyond very low frequency, due to the phase shifts.

Did you measure THD at the o/p under a real world load?

BTW, those that think the incoming mains is a nice 50Hz (or 60Hz) sine, think again

Here's mine at various times of day, it peaks around 5-6% THD at busy times, drops to 1/2 to 1/3 this late at night, with mainly the high-order harmonics falling...

[grataku]

Originally posted by ALW


The issue here Fred, as Martin alludes to, is the step-up transformer raises o/p Z.
Here's mine at various times of day, it peaks around 5-6% THD at busy times, drops to 1/2 to 1/3 this late at night, with mainly the high-order harmonics falling...

What about building a HUGE low pass filter?

[ALW]

What about building a HUGE low pass filter?

Well, it's an option, but the cure can then becomes more of a problem than the disease.

The problem here is that the mains distortion comes primarily from the non-linear loads connected. Most LPF's I've tried raise mains Z to much, and this is actually more audible than the distortion already present and whilst isolating the equipment from the mains distortion, it then increases it within the device, due to the small conduction angle of rectified mains supplies.

Some attention to power factor correction is the order of the day, I feel.

Interestingly the power plant devices have the option of more distorted, non-sinusoidal ouptuts, which are reported to sound better - I wonder if it's some simple attempt at pre-distirtion, in an attempt to improve the result under load?

Andy.

[jackinnj]

this is the filter used in one of the ARRL power supply designs:

[grataku]

Originally posted by ALW


Interestingly the power plant devices have the option of more distorted, non-sinusoidal ouptuts, which are reported to sound better - I wonder if it's some simple attempt at pre-distirtion, in an attempt to improve the result under load?

Andy.

I wouldn't exclude that at all. The shape and the harmonics come from the way the alternator is designed, the shape of the sin output is a direct result of how the "lobes" (for lack of a better english word) of rotor and stator. I think the only thing they care about is efficiency, there are some minimum output shape requirement but the rest is pretty much done in function of efficiency. That is efficiency at steady state and nominal load, which is the only way generators operate.
Harmonics add nothing to efficiency, they actually add to the useless power that needs to be dissipated in the step up and down transformers and as such an attempt is made to minimize them as much as possible during generation.
As stated before, a large portion of harmonics are generated by the load.
In some parts of europe power users above a certain number of kW are required to rephase their inductive or capacitive loads so as to "look" resistive from the standpoint of the supply that helps ,I think.

[fdegrove]

Hi,

In some parts of europe power users above a certain number of kW are required to rephase their inductive or capacitive loads so as to "look" resistive from the standpoint of the supply that helps ,I think.

It used to be like that more than 20 years ago for appliances consuming kWs.

Not anymore nowadays for the average household but still the norm for industrial apps.

Cheers,