Motor/Generator Analysis

My earlier note assumed that you were varying capacitance or frequency and wondered why you observed no significant hump - this could still happen

With regard to the software difficulty I think you are misreading the results. Using your values, the program correctly arrives at a Q of

2.2 which produces an impedance hump reaching 127ohms.

The pretty irrelevant comment "****No impedance hump" simply states that if you increased R to 80ohms the hump would vanish.

Jim

Reply to
pentagrid
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Many thanks to Jim and other contributors to the thread "Motor Generator Analysis".

I have put a lot of money and time into this, and I want to give it my best shot, but I don't want to whip a dead horse, so to say.

Frankly, I don't understand magnetics. At least not as I understand resonance. I'm an amateur musician; I understand resonance and know a little about phase shifts near the peak. I do understand that because the slope of the curve is negative on the high-frequency (capacitative) side of resonance, loading of the generator, within limits, will result in additional power to meet the load.

But B x I makes my head spin. I'm fine in 3 dimensions. So I get some of it. And I get that in the cylindrical coordinate system, B and I can be locally orthogonal, and can vary in time, with phase shifts, while being wrapped into a connected topology. I just don't feel that the way I feel resonances. It's not intuitive.

Would replacing the rotor "windings" with copper wire or bus bar (easy), and rewinding the stator with bigger wire (hard) have any chance at all of working together by lowering the leakage inductance and rotor resistance to allow resonance?

That's my best question; is there any hope at all?

This is a one-off demo, not a production prototype!

Yours,

Doug Goncz Replikon Research Falls Church, VA 22044-0394

Reply to
DGoncz

Well, let's touch base with reality here.

What do you actually have? A bicycle with a generator?

Let's get to the basics. Don't pull theory on these frat boys, they'll tear you to ribbons.

What do you have now, and what are you trying to accomplish?

Thanks, Rich

Reply to
Rich Grise

Sorry to miss your reply, Rich.

There have been a few different configurations on road.

There was a motor, glued to the V in the bottom bracket on the mountain bike. An EROS bike motor, with an adapter to the custom cogs Jensen made. And a chain to a right hand crank and cogs, with the pedal tending to unscrew. And a Bicycle Lighting Systems PAR 35 6VDC light. This rig didn't work real well, so I made a motor mount, and got a bigger motor.

The Ametek servo motor is 4" OD and 5" L. See ftp://users.aol.com/DGoncz for photos of the trapezoidal mount with hose clamps, low in the V near the bottom bracket. Not bad. Rode up hill at night with the B.L.S. light.

Then there was the big round disk covering the main triangle. Of 3/4 inch LDF. This allowed for chain drive from the pedals or the rear wheel. The rear gear on the mountain bike was brazed from a steel BMX spider and had a bottom bracket lock ring on it. It mounted to the flip flop hub, relaced to the rim.

With that rig, I added ultracapacitors. Eight PC 2500 2700 F 2.5 V caps from Maxwell, surplus. And a digital dashboard.

The caps were never used on the recumbent. The Ametek motor mounts under the seat back bag on the Thunderbolt. The mount was made of plastic drain pipe. Eventually it became clear that an idler was needed to keep the chain on the rear cog, which was made from a Big Cheese BMX chain ring holder, mounted on a mountain bike disc hub, relaced to the rear rim.

That was the rig in the videos at ftp://users.aol.com/DGoncz. New Year's Eve. 24 watts of Christmas lights on the bike, driven by the Ametek and an inverter.

There was also the AC generator, subject of this thread, painstakingly mounted to the front derailer post. One day, the Ametek drove the inverter which drove the front motor/generaor in motor mode. It was a shakedown.

What I am trying to accomplish is to provide all the electrical needs of an infantry soldier, with reasonable mobility and load carrying ability, on dirt roads, whether riding or stopped, such that the only resupply will be ammunition and food. Currently we resupply a lot of primary and secondary batteries to our infantry. An awful lot. A mobility and operational capability restricting large quantity, in fact.

Doug

Reply to
DGoncz

If you posted all that in English u might get more feedback.

I would start at this point if I were you, because I think your idea of a way to do it is fundamentally flawed.

Using a soldier to manually generate electricity will impose substantial extra physical demands on him. This means healthy soldiers will cover less miles, do less work, arrive more tired, and generally make them an inferior fighting force. Hardly what you want in your military!

The whole idea with power is to have the power help the user, rather than the user slave away to produce the power. One helps, the other hinders.

This issue makes your whole approach a dead duck in most situations. It may have its apps, but will be deprecated in most situations.

More logical would be a solar panel on the bike. Even supplying endless batteries is better that pedal power, when you can provide those supplies.

NT

Reply to
bigcat

I believe a bicycle coasting down a hill normally travels faster than a walking soldier. If generator output allows power capture on coasts, reducing speed to walking speed, then as far as mobility goes, on dirt roads, it's a dead heat for speed, with the bicycle/generator out ahead in terms of independence from supply.

Doug

Reply to
DGoncz

On Sat, 02 Jul 2005 15:10:26 -0700, bigcat wrote: ...

...

Hey! Works for me! ;-P

Cheers! Rich

Reply to
Richard the Dreaded Libertaria

Yabbut, who gets volunteered to push the damn thing back up the hill?

Thanks, Rich

Reply to
Richard the Dreaded Libertaria

Yabbut, which is easier, backpacking 1000 feet vertical with 70 pounds on you, or pedaling a 100 pound bicycle up the equivalent road? I admit bikes can't go everywhere, but anywhere they go they are more efficient than porting a load.

Doug

Reply to
DGoncz

If you actually work out how much energy you can capture that way, I think youll find it disappointing.

NT

Reply to
bigcat

Dear NT,

I have worked it out. I was impressed, not disappointed. I have actually captured such energy. I was more than impressed, I was frightened. I had to slam on the brakes before I damaged the wiring and components with the several hundred watt power surge.

Doug

Reply to
DGoncz

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