@BobTPH

We are attempting to develop a utility patent for friction surfaces to hopefully market to manufacturers in the automotive, and other industries. We are in the proof of concept stage. Part of my duties is saving money.

Building a circuit from transistors or vacuum tubes would require too much time, and the result would certainly be of lower quality than a commercial product. I posses neither the time or skill required for that.

BobTPH wrote "As I understand it, you want to take a signal from a signal generator and amplify it to about 20KW of power, without transistors. I suppose you could do it with vacuum tubes... I do not know of any other device that might do that kind of power amplification, especially because you want it done "cleanly," as you say."

Yes. And thank you, that answers my question

BobTPH wrote "Here is a helpful suggestion. Rent some industrial space with 3 phase 480V power available."

So, the cost of commercial space is quite expensive, and many will not allow, or are not zoned for what we are doing. Strip mall type spaces all told us "no welding or open flames" "Noise below certain db". Most of those were around 1.5k - 3k a month, while light industrial spaces were around 2.5-8k a month. I rented a house in the county with a large garage, no zoning restrictions (some restrictions but they wont apply to us) on 7 acres of land for $900/mo. But of course, 3 phase power is not available. In some cases you can pay to have you transformer on the pole swapped out and get 3 phase, that inst an option either. We will still save more money in any scenario than to rent commercial space.

@crutschow wrote "Your requirements are vague.You (apparently) want to generate AC power but you can't generate that from nothing."

They are not vague. I have mentioned several times

crutschow wrote "Okay. So where does this "source" get its power? And converting that to AC is normally done with a transistor inverter."

DC current source would have been rectified AC from 240V split-phase, I can supply several of these. I'm aware of the typical method of producing current, I was hoping there was something else. It doesnt look like there is.

crutschow wrote "If there were a simpler or better way to do that, then it would already be done.That is as helpful as suggestion as you are likely to receive."

That is in fact what I need ed to know thank you guys.

I will give a couple of examples of thing I have done. We needed a 3 ton gantry crane. The quote was 15k. I built it for around a grand and 20hrs labor (including sourcing materials). We needed air service 24 CFM %100 duty cycle. The LOWEST quote was 12k. Again I installed it for around a grand and about 20hrs labor including sourcing materials.

The next best option is to buy an older rear wheel drive diesel ie. 89 volvo, pull the tranny, gut the interior trim,and drop in a 20kW 3 phase generator. I think I can do it for under 10k. More than I wanted to spend, but way less than a commercial option.

I will leave notifications on for the next day in case anyone has anything to add. Thanks for all the help.

 

If you need a certain output power, say, 10 kW, and you want to stick with all linear components (linear power amplifiers, signal generators, low frequency power transformers, etc.) then you will need an external power source of at least 15 kW. At these power levels, nothing is very efficient.

The overall plan - generate low energy 3-phase sinusoidal AC and amplify it - is fine on paper. The problems are doing it with real life components, and powering it. In post #3 you mention developing your signal up to 100 W. OK, very easy. But that is only 1% of the final output power. Where does the other 99% come from? Not the transformer. It can step voltages and currents up and down all over the place, but no matter what the output, it will be less than 95% of the input power.

ak