Electric Motor Secrets

[Peter Lindemann]

Right

Um, if one puts a diode cathode on battery negative and diode anode on the negative side of the capacitor, wouldn't that block current from capacitor to battery?




I suppose one should connect recovery coil to capacitor with appropriate diode in between? Otherwise it wouldn't make sense (at least to me it wouldn't).

Lighty,

Yes, the idea is to block the energy from going back to the battery. Why? Putting the energy back on to the RUN battery is the same as throwing the energy away, because the battery cannot be charged and discharged at the same time. In the arrangement I am suggesting, the capacitor acts as a buffer stage. Its voltage will never drop below the battery voltage, but it may rise above the battery voltage whenever the return energy pulse arrives.

The isolated output coils already have their respective diodes associated with them to block any current flows during the input phase, so they only allow current to flow during the magnetic field collapse phase. When you collect the output energy from the same winding as the input, the output current is reversed and cannot be applied back to the front of the circuit without producing a short circuit in the system. By collecting the output on an isolated winding, the problems associated with this current being in the opposite direction are negated, so the energy may be applied directly back to the front of the circuit with no other complications.

This frees the system from needing a second battery to receive the recovered energy.

The idea is to optimize the circuit conditions for this recovery mode, so the motor can be run by simply replacing that fraction of the energy that is NOT recovered. When this circuitry is coupled with a mechanical section with a very small air-gap, so that the mechanical torque production is high, the probability of running the COP>1 is also very high.

Peter

[sykavy]

Sykavy,

CAST IRON is an industrially available metal. Whether or not it is readily available near you is beside the point. That you do not know this, or even know how to find out, is a reflection on your general lack of scientific knowledge. Even the assumption on your part that you could some how make your own "cast iron" by melting down "old drain pipes or car radiators" shows a complete lack of understanding.

Just to clarify, I am not suggesting that you cast your own iron.

This forum is about experimental electric motor building. Casting your own metal alloys is an experiment in metallurgy. That you would even suggest this is shocking to me. Your lack of knowledge about electric motors and electronics in general is profound, but the idea that you would attempt to begin a project like this by casting your own iron core is beyond my comprehension.

Over the last 6 months, I have been extremely patient and polite with you, but I am going to draw the line right here. I will not offer you any help with such a project. If you attempt any of this, you are totally on your own. I will not be drawn into a discussion about casting techniques, raw materials stocks, fluxes, slag, molds, or the like. Any posts on these subjects in this forum will be deleted.

The scientific knowledge base and engineering skill set required for success in the project of building your own experimental electric motor is considerably beyond your current abilities. A reciprocating solenoid engine like Teal's is a complex electro-mechanical machine. Building one from scratch is very difficult. Building one by modifying an existing internal combustion engine is no less difficult. Please don't waste any money by starting a project you are unlikely to be able to finish successfully.

Peter

I understand that I may seem foolish in wanting to cast and that point is well taken. My friend, who is experienced in casting, will be handling the iron part. I had no intention of drawing the tread away from its purpose or asking you metallurgy questions.

I know my knowledge is limited but I have to start somewhere. You have been patient with me and I thank you for that.

Ok if you say that I'm on my own.

I'm still going to try and make it from what I understand from this thread and your DVD. I never intended to be a problem. I know I may be naive but I am sincere in my interest in your project and I'm willing to learn. So for now adieu

[Aaron]

start new thread

Hi Sykavy,

You're welcome to start a new thread on iron casting as it relates to building rotors, cores, etc... so that it ties into a renewable-energy topic. I don't know anything about it but I'm sure there are others that can kick around some ideas with you on this. If you don't mind doing that, I'll clean this thread up a bit.

[Jetijs]

Ok, here is a little update.
At first I was getting some random results because the primary battery was depleted and lost voltage very fast while motor was running. So instead I used a variac vith a bridge rectifier and 20 000uF smoothing capacitor. This way I could get a steady DC. At first I tried how much energy I could get back if I increased the voltage and thus the speed of the motor. Here are my results:


Test1
IN____19.0V___1.37A___26,03W___100%____2241RPM
OUT__24.0V___0.13A___3,12W____11,98%___2241RPM

Test2
IN____23.1V___1.57A___36,26W___100%____2516RPM
OUT__24.0V___0.20A___4,80W____13,23%___2516RPM

Test3
IN____25.1V___1.67A___41,91W___100%____2632RPM
OUT__24.1V___0.232A___5,583W____13,34%___2632RPM

Test4
IN____27.2V___1.76A___47,87W___100%____2750RPM
OUT__24.2V___0.27A___6,53W____13,64%___2750RPM

From these tests i figured that increasing voltage/speed is one way to get better IN/OUT ratio in percentage. But if I would like to get something like 80% back, I would have to increase the speed to maybe 6000-8000RPM. I doubt that my motor could handle that speed, even now when the motor is running at about 2500 RPM, it is very loud and it is hard to speak to someone in the same room. So increasing the voltage and thus the RPM's is not the way to go.
I also tested what the difference between two circuits is (isolated output and non isolated output). Here are the results:

Test 1 Isolated output
IN____23.4V___1.59A___37,2W___100%____2537RPM
OUT__24.1V___0.20A___4,82W___12,96%___2537RPM

Test 2 NON isolated output
IN____23.4V___1.58A___36,97W___100%____2531RPM
OUT__24.1V___0.20A___4,82W___13,03%____2531RPM

From these tests we see that ihe non isolated output works just a tiny little bit better. The amp draw is a little bit less and so are the RPMs at the same voltage.

So next I looked at the input current waveform and the top line. I figured that in order to get the perfect wave (only a straight line) I have to decrease the ON time two times, but when doing that I have another 15 degree left on my 30 degree operation window, also only one such perfect impulse would not deliver enough power to get the motor to high speeds, so I figured I will make a commutator wheel that gives two impulses per rotor leg (30 degrees), not just one. That way I could deliver about the same amount of power to the stator coil and get two pulses with better waveform and thus IN/OUT ratio. Here is what I mean:


So I made the timing wheel this way:


Each gap is 7,5 degree of an arc, total ON time is the same (15%) and there is plenty of time left for the BEMF fall time. Here is the waveform I got now:


And here are the test results:

Test 1
IN____25.4V___1.27A___32,25W___100%____1815RPM
OUT__24.2V___0.24A___5,80W___17,98%____1815RPM

Test 2
IN____30.0V___1.38A___41,40W___100%____2237RPM
OUT__24.5V___0.34A___8,33W____20,12%____2237RPM

So here we see, that with these two pulses instead of only one, we get more back with less speed and current draw
The best achievment yet is 20.12% recovered energy.
Any comments?
Also, Peter I think you missed my post with a question about motor loading in the previos page

Edit: I made another timing wheel with three gaps (5degree of an arc).



Here's how the waveform looks:


I tried several timing adjustments and voltages. The best result I got so far is 24,25% recovered energy.


Thanks,
Jetijs

[Peter Lindemann]

Totally on the Right Track

Ok, here is a little update.
At first I was getting some random results because the primary battery was depleted and lost voltage very fast while motor was running. So instead I used a variac vith a bridge rectifier and 20 000uF smoothing capacitor. This way I could get a steady DC. At first I tried how much energy I could get back if I increased the voltage and thus the speed of the motor. Here are my results:


Test1
IN____19.0V___1.37A___26,03W___100%____2241RPM
OUT__24.0V___0.13A___3,12W____11,98%___2241RPM

Test2
IN____23.1V___1.57A___36,26W___100%____2516RPM
OUT__24.0V___0.20A___4,80W____13,23%___2516RPM

Test3
IN____25.1V___1.67A___41,91W___100%____2632RPM
OUT__24.1V___0.232A___5,583W____13,34%___2632RPM

Test4
IN____27.2V___1.76A___47,87W___100%____2750RPM
OUT__24.2V___0.27A___6,53W____13,64%___2750RPM

From these tests i figured that increasing voltage/speed is one way to get better IN/OUT ratio in percentage. But if I would like to get something like 80% back, I would have to increase the speed to maybe 6000-8000RPM. I doubt that my motor could handle that speed, even now when the motor is running at about 2500 RPM, it is very loud and it is hard to speak to someone in the same room. So increasing the voltage and thus the RPM's is not the way to go.
I also tested what the difference between two circuits is (isolated output and non isolated output). Here are the results:

Test 1 Isolated output
IN____23.4V___1.59A___37,2W___100%____2537RPM
OUT__24.1V___0.20A___4,82W___12,96%___2537RPM

Test 2 NON isolated output
IN____23.4V___1.58A___36,97W___100%____2531RPM
OUT__24.1V___0.20A___4,82W___13,03%____2531RPM

From these tests we see that ihe non isolated output works just a tiny little bit better. The amp draw is a little bit less and so are the RPMs at the same voltage.

So next I looked at the input current waveform and the top line. I figured that in order to get the perfect wave (only a straight line) I have to decrease the ON time two times, but when doing that I have another 15 degree left on my 30 degree operation window, also only one such perfect impulse would not deliver enough power to get the motor to high speeds, so I figured I will make a comutator wheel that gives two impulses per rotor leg (30 degrees), not just one. That way I could deliver about the same ammount of power to the startor coil and get two pulses with better waveform and thus IN/OUT ratio. Here is what I mean:


So I made the timing wheel this way:


Each gap is 7,5 degree of an arc, total ON time is the same (15%) and there is plenty of time left for the BEMF fall time. Here is the waveform I got now:


And here are the test results:

Test 1
IN____25.4V___1.27A___32,25W___100%____1815RPM
OUT__24.2V___0.24A___5,80W___17,98%____1815RPM

Test 2
IN____30.0V___1.38A___41,40W___100%____2237RPM
OUT__24.5V___0.34A___8,33W____20,12%____2237RPM

So here we see, that with these two pulses instead of only one, we get more back with less speed and current draw
Any comments?
Also, Peter I think you missed my post with a question about motor loading in the previos page

Thanks,
Jetijs

Jetijs,

You have entered the zone of self-learning where you can see what the motor's behavior is teaching you!!! You can begin to see that by properly limiting the input pulse to just what you can get back, the motor can run 55% of the time on your applied currents and 45% on the recovered currents. The recovered currents increased when you chopped the ON-TIME window into two parts. But you are still ON for too long for the magnetic behavior of your stator.

The LAST TRICK to fine tune this arrangement is to open up the ON-TIME window on your commutator wheel to about 25 degrees, and flash the LED at the inductive rise-time rate. This keeps the motor in the maximum energy recovery mode regardless of speed or loading. From the looks of your recovery wave-form, it looks like the optimum ON-TIME is between one and two time divisions on your scope.

Make a little 555 timer circuit and chop the LED front end of your optical commutator with a 50% duty-cycle and an ON-TIME equal to about 1.5 time divisions on your scope.

Now, it is just about maximizing torque with small air-gap, maximizing energy return with proper input chopping and recycling the recovered energy back to the front with an isolated output winding.

That's it! You now know how to make the machine work.

Peter

[Jetijs]

Thanks Peter
The idea about the 555 timer flashing the LED is great, because I can't really squeeze more than three pulses in this 30 degree window on my timing wheel due to the need of very small endmill bit diameter. I should be able to do this LED flash trick easily. Flashing the LED with 50% duty cycle will also make it consume less power. I will try this and post the results

Thanks,
Jetijs

[Peter Lindemann]

Make it Variable

Thanks Peter
The idea about the 555 timer flashing the LED is great, because I can't really squeeze more than three pulses in this 30 degree window on my timing wheel due to the need of very small endmill bit diameter. I should be able to do this LED flash trick easily. Flashing the LED with 50% duty cycle will also make it consume less power. I will try this and post the results

Thanks,
Jetijs

Jetijs,

If you make the 555 timer circuit with a variable pot, you will be able to dial up the perfect chopping frequency to maximize the energy recovery. Once you know the right frequency, you can hardwire the circuit for those values.

Once you have the new rotor with the micro-clearance air-gap, we can go through each system one more time to balance the motor at a higher power level.

Great work!!

Peter

[MHZathras]

The first waveform shows the peroid of the pulse. The curving rise time replesents the slew rate of the charging cycle of the on switch. It has a low pass filter tendency (slow rise time). The second wave form is from a longer period of repetition or lower rpm, same approx slew rate. The third wave form, assuming the controls for the scope are not changed, is an even slower rpm (ergo longer period of cycle) It has reached a saturation of some sort(most likely the power supply maximum voltage). Spectrally you could deduce their are more high frequency harmonics in the wave form. Mostly odd harmonics... But with the non linearity of the circuit with it high constituents of inductive reactance. I would guess that there are some even harmonics as well (sum and difference componects of the sum and diference componets, that are odd harmonics (3f-5f=2f etc.)

Wow, sorry guys I was trying to reply to a post on 11-22-2007, 01:55 PM and it landed here. I guess that is why I am called a junior member. I have been a linear and digital electronics engineer for a very log time. But I still have problems with BBs, Forums, and postings.

Sorry, maybe someone can put this post where I meant it to be. Just trying to contribute.

[Jetijs]

Hello everyone.
Today I played around with 555 circuits. I could get the frequency easily, but the thing is that a simple 555 timer can't get you a perfect 50% duty cycle. You can use a flip flop to solve this. I did this a while ago when I atempted to buid a Tesla switch. Unfortunately I lost all my circuit examples when the hard disk array on my computer crashed. But I guess I don't need a perfect 50:50 duty cycle, 50.001:49:999 will do just fine. I just need some positive voltage regulators, because my system runs at 24V and the 555 timer can handle max 16V. I think the LM7812 will do just fine. Here is the data sheet:
LM7812 datasheet pdf datenblatt - Fairchild Semiconductor - 3-TERMINAL 1A POSITIVE VOLTAGE REGULATORS ::: ALLDATASHEET :::
Also I have a question. When I make the efficiency tests, the output battery gets charged with each test and there is only a little pause between tests. The battery gets to a higher voltage with each next test thus giving me better results, but this is not acurate. Also if a test is longer, the battery gets charged higher at the end of the test. Maybe someone has a different idea how to calculate the output energy more precize?
Thanks,
Jetijs

[Peter Lindemann]

A Few Ideas

Hello everyone.
Today I played around with 555 circuits. I could get the frequency easily, but the thing is that a simple 555 timer can't get you a perfect 50% duty cycle. You can use a flip flop to solve this. I did this a while ago when I atempted to buid a Tesla switch. Unfortunately I lost all my circuit examples when the hard disk array on my computer crashed. But I guess I don't need a perfect 50:50 duty cycle, 50.001:49:999 will do just fine. I just need some positive voltage regulators, because my system runs at 24V and the 555 timer can handle max 16V. I think the LM7812 will do just fine. Here is the data sheet:
LM7812 datasheet pdf datenblatt - Fairchild Semiconductor - 3-TERMINAL 1A POSITIVE VOLTAGE REGULATORS ::: ALLDATASHEET :::
Also I have a question. When I make the efficiency tests, the output battery gets charged with each test and there is only a little pause between tests. The battery gets to a higher voltage with each next test thus giving me better results, but this is not acurate. Also if a test is longer, the battery gets charged higher at the end of the test. Maybe someone has a different idea how to calculate the output energy more precize?
Thanks,
Jetijs

Jetijs,

I love the way you just jump on this stuff. Anyway, here are some simple solutions to the problems you are having.

1) Don't worry about the perfect 50% duty cycle with this set-up, it just doesn't matter. 51% - 49% is plenty good for this.

2) Run the 555 timer circuit and the LED portion of the optical commutator from just ONE of your 12 volt batteries. This portion of the system isn't connected to anything else, so it doesn't have to be run on the 24 volt system.

3) For efficiency tests, go back to running the little light bulbs.

Good luck,

Peter

[Jetijs]

Thank you Peter!
The idea of using only one 12V battery to power the 555 is so simple that it is almost embarrasing that I did not think about that Anyway, here is the picture of the whole circuit that I am indending to use:

I think that it is all right here, but just to be sure I need someone to verify this
Thanks,
Jetijs

[Peter Lindemann]

Pretty Good

Thank you Peter!
The idea of using only one 12V battery to power the 555 is so simple that it is almost embarrasing that I did not think about that Anyway, here is the picture of the whole circuit that I am indending to use:

I think that it is all right here, but just to be sure I need someone to verify this
Thanks,
Jetijs

Jetijs,

Looks close. Pin 4 of the 555 needs to be tied to the +12. I think if the capacitor is about .01uf, the resistor between Pins 7 & 8 is a 10k resistor, and the resistor between Pins 7 & 6 is a 1M pot, you should be able to play with the pulse width to find the inductive rise-time of the coil and a good percentage energy return. Play around with it, as I may still have this wrong. I don't use 555 timers in the standard mode very much, and I don't have this stuff memorized.

You may also have to lower the value of the resistor on the LED to get the same brightness as the 1k across 24 volts. The output at Pin 3 is not the full +12 volts.

Other than those minor things, it looks good to try.

Have you opened up the window in your commutator wheel to 25 degrees?

Peter

[Jetijs]

Ok, thanks Peter
I have not made a new comutator with a 25 degree gap yet. I will first solder the 555 circuit and test it with a scope.
I think I have all the info now to proceed

Jetijs

[amigo]

Jetijs,

If you need a good square wave oscillator, please check LTC1799, here's a link to one circuit: Electronics -- Small Footprint Square Wave Oscillator

[Peter Lindemann]

Steven, are you still here?

Steven,

After showing us those excellent photos of your motor a few weeks ago, we haven't heard from you.

Can you give us a progress report?

Thanks,

Peter