Electric Motor Secrets

[Jetijs]

Hi lighty
I am using those cheap multimeters that can measure up to 10A of current. I tried to get a shunt out from a cheap meter, but there was just a thick copper wire used as a shunt with no specs on it, so I can't use that. I also searched for some shunts in local electronics shops, but they do not have anything around, I can just order some from them, but they are charging about 50$ a piece for a 5A, 60mV shunt, like this:

So I really have not pursued the shunt measuring idea
What about these shunts:
20A 75mV DC Current Shunt Good4 Digital Analog meter - eBay (item 350072790126 end time Jun-29-08 09:16:37 PDT)
do you think they would be suitable? If yes, I will buy them now!
Of course, I am not an expert, but do you really think, that all those spikes would make an error this big on my cheap amp meters? The power supply current reading is about 30% less than the amp meter reading, but that, of course, is because of the recovery. I mean, to get at least 60% efficiency in my calculations, it would require a current draw of about 1A (instead of 2.45) for the same other readings. Could those spikes make an error this big on the meter?
Maybe the problem is somewhere else
Thank you!

[lighty]

It really depends on the ampermeter and on the ammount of transients getting to it that it's capable of registering. As for those shunts- yes they would do fine if your oscilloscope is capable of measuring signals with resolution of at least 3.75mV or better (75mV/20A = 3.75mV/A).

I'm not saying that ampermeter is making erroneous readings but rather that you should eliminate that possibility in order not to start making adjustments on the motor that are possibly not needed. Consider it a precaution.

[Tishatang]

Solenoid piston engine

Hi All,

I am so glad I found a link to this forum. I call this thread the Zen of R & D.

I am in China and not able to get the Attraction Motor DVD, but I have some of Peter's books in my library at home.

For those of you who are interested in a solenoid piston type motor, go to this link:

Green Steam Engine Home Page

I refer to it as the "Lean, Mean, Green Machine". Perhaps Aaron can start a new thread for discussion. I feel this is the one to build.

Tishatang

[Aaron]

new thread

Hi Tishatang,

Yes, that is a very neat way to make a steam engine. It has been posted a few times on this forum in different threads.

Anyone call feel free to start a thread at any time on any topic.

When you're in the main renewable-energy forum:
http://www.energeticforum.com/renewable-energy/

Towards the left side, you'll see a button to start a new thread. Simply click that and start one on that steam engine or anything else.

[vzon17]

Soleniod piston engine

Hi All,

I am so glad I found a link to this forum. I call this thread the Zen of R & D.

I am in China and not able to get the Attraction Motor DVD, but I have some of Peter's books in my library at home.

For those of you who are interested in a solenoid piston type motor, go to this link:

Green Steam Engine Home Page

I refer to it as the "Lean, Mean, Green Machine". Perhaps Aaron can start a new thread for discussion. I feel this is the one to build.

Tishatang

So are you suggesting to make an engine like that with electric solenoids on it instead of steam? that might be intersting. When I look at that setup I have a hard time figuring out how it makes rotation or how much torque it would have.

[Peter Lindemann]

OK, Let's Start from the Beginning..

Peter,
http://www.emuprim.lv/bildez/images/..._1/shema12.GIF
this is the circuit I used with the amp meter in it. It shows the current that the motor is actually using. If I connected the ampmeter between the insulating diode and power supply negative terminal, it would show less current (only the part that is taken from power supply). When I made these tests, I used the same commutator wheel as before, it has one 65 degree gap on each side (180 degree apart). There was no LED pulsing, so the energy recoverey was at about 30-35%
I also made changes in my calculations so that only the difference in both scale readings is used to calculate the torque, this gave even worse results with efficiencies around 20%. Test results where there was a deflection only in one of the scales, remained the same. I used a rather narrow leather strap, about 4mm wide (did not have anything better). Using this strap I could load the motor with up to 25 grams till the other scale also started to deflect.

Anyway, the calculated efficiencies are so low, that either I did a mistake in measurements/calculations, or there is something wrong with the motor.

Thank you!

Dear Jetijs,

Thanks for the schematic and the rest of the brief report. With the ammeter where it is shown, it will show the true current use of the system. You will need these readings at certain points along the way. But this is not where to have the ammeter to determine if the unit is operating at COP>1. That location is right before the diode on the negative line coming out of the supply.

Before we go any further, I'd like to say that it sounds like your dynamometer wheel and leather strap are working OK and that you are becoming familiar with the process of taking these measurements. Operating a dynamometer is an art unto itself. Learning how to use it properly can take a bit of practice. You might consider placing an off-the-shelf DC traction motor on your dynamometer system and practice taking some readings.

The next thing I would like to discuss is your timing. Right now, you say that the optical interrupter has two 65 degree open windows and that you are running without pulsing the source diodes. This opening is probably too large to run the motor efficiently without diode pulsing simply because the open window is more than half of each power slot (90 degrees). So, your "first test" results are not surprising.

What I would like you to do is think through all of the functions of the motor and review all of the data on your previous tests. Then determine where you think the high efficiency window is going to be and how to test the motor under those operating conditions. You have built an excellent "test stand" and now you have all of the tools to begin a real testing program.

You and Lighty have already run some tests showing you can recover over 65% of the electricity, under favorable circumstances. Now that you have the dynamometer, it is time to determine what it takes to get the most torque out of the machine and the speed and timing required to do that. Then see if you can adjust everything so those two windows coincide with each other. That is where you will find the COP>1.

Best wishes,

Peter

[Jetijs]

Peter,
that is a great idea of getting an of the shelf DC motor to practice in measuring efficieny. This way I will be be sure, that there are no problems in my measurements and calculations. And when I will be certain that I am doing everything right, I will measure the efficiency of the motor at its highest recovery configuration with the amp meter placed where you said it should be.
This could take a while, because I am still busy with my other project that is taking more time than I estimated. I will keep you informed.
Thank you!

[aladinlamp]

Stator shapes

Hi

Which one of these could be most efficient considering just shapes not dimensions?

Thanx

[lighty]

But this is not where to have the ammeter to determine if the unit is operating at COP>1. That location is right before the diode on the negative line coming out of the supply.

Umm, ampermeter should also show total system input if located directly on + or - of battery. I suggested placing it on + branch, you suggested placing it on - branch. Both of those solutions should be correct in this case. Am I missing something or is there any significance in placing it on the - of battery?

[Tehnoman]

Well, the global assumption is that current flows from "+" to "-", reasons are quite historical, If I am not wrong. Yet, later it was discovered that electrons flows in different direction, that is from "-" to "+". When placing ampermeter in "-" side, we measure electrons, that comes out of battery, but in "+" side - electrons, that comes back to battery, after going through all components of circuit. I can't imagine any reasonable way how these values could differ, but you can simply verify it - place two ammeters, each at different side!

[lighty]

@Tehnoman

I know the history of the marking convention however when dealing with closed path circuits I never noticed any difference when measuring total current on either side of power supply or battery.

[Tehnoman]

True. So, you answered your question. By the way, it doesn't matter whether you are getting additional ZPE in your system, it won't generate excess electrons at any side of battery. Or else it would change the charge of environment aroud your circuit, and that you would notice, as air is good insulator and eventually it would set up some kind of discharge or spark!

[lighty]

Yup, I know all that. It's just that Peter formulated his response to Jetijs in a way that is different than mine and I just wondered if it has any significance.

[Tehnoman]

Glad to hear that. I saw Peter's answer to Jetijs, just looked to me like a question about obvious.

Good luck!

[hh1341]

Hi All,

I may be mistaken, but I get the impression that Peter favours the rotary type of attraction motor.

I may have gotten interested in the solenoid type because Peter devoted so much of his time on the DVD, to it.

Perhaps I should drop it and follow Jetijs’ lead?

Carl