Easy no BEMF motor with brushed motor

[sucahyo]

This is my version of a motor that reduce its current consumption on load. It is easy and do not require custom part for the motor. You can use available brushed dc motor. I use brushed dc motor in place of my stingo coil.

The circuit:





In this configuration, the motor behave the opposite of what it normally does. Input current will increase the faster the motor goes. At lower rpm it barely have power / torque, so I have to forcefully rotate it up to speed.

Youtube - Brushed motor as coil, slower = less torque...

Youtube - stingo with brushed dc as coil

If we add load in the radiant recovery part, the battery will see it as load in series and reduce the power transfered to the motor and reduce its speed. Raising the current by changing potentiometer allow motor to run faster.

However, there is side effect. The maximum current reduce in half, halfing the motor speed. To reach original speed, more voltage is needed.

[juju]

hmm

hello sucahyo how r you?

very intesresting project...

how r you shore you dont have any BEMF?

hugs

[sucahyo]

how r you shore you dont have any BEMF?

Because my motor draw more current the faster it spin.

I currently define the following terms this way:
BACK EMF is the reverse, generated voltage in an induction motor. This effect allows the motor to be self-regulating and draw LESS current the faster it spins.

The faster the coil moves, the more the coil will generate back EMF to counter your input. THIS is the process that limits the overall efficiency. In this sense, your set-up will behave "classically" and the probability of COP>1 operation is low.

Your idea of how to produce more mechanical energy may be correct, but it will not increase the EFFICIENCY of the system above the limits set by "reverse generator effects".

A motor can only produce a COP>1 IF the forward EMF to back EMF ratio is greater than one, AND/OR any electrical energy recovered is recycled for re-use.

Peter

Not sure how to measure COP. But surely COP>0 .


OFF TOPIC (not sure where to put it):
Currently playing with another touchy circuit lol.
YouTube - Touch activated JT



As unusual, input current reduce with load .

[Peter Lindemann]

You Misunderstand Me

Sucahyo,

The circuit you propose does not change the underlying function of the motor it is attached to. Whether the motor produces Back EMF (a reverse generated voltage) is purely a function of the geometry of the machine. If the motor runs on one of the variations of Michael Faraday's "direct induction" principle, then it WILL produce both Forward MMFs (forward motor forces) and Back EMFs (reverse electric forces) in varying proportions, depending on speed.

Your circuit may change the APPEARANCE of the motors responses, by limiting the current at start-up speeds, but it cannot overcome the physical construction of the motor and the fundamental geometry and principle of direct induction upon which it is based.

If the motor operates with Back EMF without your circuit, it still operates with Back EMF with your circuit, regardless of what it may look like.

Sorry.

Peter

[sucahyo]

If the motor operates with Back EMF without your circuit, it still operates with Back EMF with your circuit, regardless of what it may look like.

I see, thanks for the correction. Too bad that it still has BEMF. It is interesting that a circuit can change motor behaviour. I wonder why nobody use this trick before.

I found that less current consumption with less RPM or halted motor can be usefull. The problem I try to solve are battery depleting fast and has hot temperature when the motor stop or run at low rpm. This is for toy mini4wd track car that use brushed dc motor. If I can make the toy to not consume current when being forcefully stopped, the battery life is prolonged at the cost of having to push the toy to make it run.

However, I found big problem. I can't find workable transistor at less than 3 volts. The motor do not start again when I give load. And It won't even start if the source voltage is too low.

YouTube - zerovoltzerorpm.avi

circuit:

[sucahyo]

Another look at relation between load and current, the input current reduce on attempt to halt the motor:

YouTube - stingo motor, input current reduce with load / lower rpm

[sucahyo]

Dr Peter Lindemann statement that my motor behave like that simply because I limit start up current may be wrong. I guess it is my fault to not let people know what my stingo can do.

I think better explanation for what cause my motor to behave like that is just because my circuit behave differently from other radiant circuit.

While other radiant circuit do not produce radiant with the secondary being shorted, mine still produce radiant. This create effect such as reduced current consumption with load, more intense DC output at secondary, and also brushed motor reduce current consumption with load.

YouTube - stingo still produce radiant even with shorted secondary

I never heard any other circuit that still produce radiant with shorted secondary. Since my circuit act differently from other radiant circuit or any Bedini derivative circuit, I think it is more appropriate not to associate my circuit with radiant oscillator anymore. I was wrong to post that my stingo as radiant circuit. It is not. While it still utilize the coil collapse current it show different behaviour from the rest.

Maybe this difference is what cause Dr Peter Lindemann to jump in conclusion.



I love to hear everyone opinion.

[sucahyo]

I just answering question at youtube. Mentioning why my motor do not work the same way as what commercially available.

At zero rpm:
- conventional dc motor will have highest input current with highest torque
- stingo motor will have lowest input current lowest torque (sometimes zero)

At fastest rpm
- conventional dc motor will have lowest input current with zero torque
- stingo motor will have highest input current with a lot of torque

Hopefully explanation bellow can give more explanation to why my motor behave differently even if it still have BEMF. My clearest video that show the effect is this:
YouTube - stingo motor, input current reduce with load / lower rpm



The explanation bellow do not apply to my stingo motor!


This site bellow has many graph about relation between input current and motor speed.

LEGO 9V Technic Motors compared characteristics

The example is this:


Notice that as the motor speed reduce, the torque increase and the current consumption raise. My motor do the opposite, as stingo motor speed reduce, the torque and current also reduce.

EV Performance Input Data

The more you load the motor, the more it will draw down the voltage across it. However, as voltage across the motor drops under load, its current draw increases. In other words, as you load down a motor, its RPM goes down and its torque increases.

Basic Characteristics of DC Motors | Technical Information | CITIZEN MICRO CO.,LTD.

Basic performance is that when torque (load) becomes higher then speed becomes lower and current becomes higher. On the other hand, when torque (load) becomes lower then speed becomes higher and current becomes lower.

This site has method to calculate BEMF:
NEC uController tools

As the motor turns, it generates a back EMF (Faraday's law) and output torque. The output torque is proportional to the winding's current:

Torque(nNm) = Km*i, where Km = 14.5mNm/A is the Torque Constant

And the back EMF is proportional to the rotor's speed.

EMF = Ke(mV/rpm)* speed(rpm) , where Ke = 1.52mV/rpm is the Back-EMF Constant

At zero speed, the back EMF is zero. Hence the current is :

i = U/R = 12/8,71 = 1.378

Therefore, the output torque is:

Stall Torque = 14.5*1.378 = 19.98 mNm // Same as specification

Note that the stalled current is very high at stalled torque and the motor's winding will heat up very quickly. If the motor is stalled for a long enough period, normally a few seconds or more, the heat generated will burn the winding.

At no-load condition, the back EMF is

U = EMF + Io*R

EMF = U - Io*R = 12 - 0.014*8.71 = 11.87volt

No-load speed = EMF/Ke = 11.87/(1.52 *0.001) = 7815 rpm // Same as specification

Note that the no-load current, Io, is required to overcome the motor's internal friction. The output torque at the motor shaft is essentially zero.

At other speed, then the torque,

EMF = Ke*w

current, i = (U-EMF)/R

output Torque = Km*i

= Km*(U-Ke*w)/R

= Km*U/R - Km*Ke*w/R

= Torque(stalled) - Km*Ke*w/R

Km*ke/R is a constant. Hence the torque vs speed curve is a straight line with a negative slope as shown below.

[7imix]

circuit:

I tried building this circuit, but I don't get the results you describe. I'm not sure if any of my DC motors are brushed. How might I be able to tell?

The motor just runs with a DC wave on the scope and draws more current when I load it.

I'm assuming the waveform getting to the motor is supposed to be an impulse wave at the resonant frequency of the motor coil. I'd really like to get this circuit working, any help appreciated.

[7imix]

Ok, I finally found a DC motor that actually was brushed. I had to scavenge cheaper components, the DC motors I got out of a sony cassette deck from the 80s were too nice, I think :-)

I was able to reproduce the results, the current draw decreases with load when hooked up to the stingo. I can also get the coil to sing like I can the car coil. When the circuit is tuned properly it doesn't sing and the motor goes full speed at 600mA compared to 800mA DC.

Here's the video, I also measure the pulses with my little scope which is great to watch.

YouTube - Stingo Motor

[sucahyo]

Ok, I finally found a DC motor that actually was brushed. I had to scavenge cheaper components, the DC motors I got out of a sony cassette deck from the 80s were too nice, I think :-)

I was able to reproduce the results, the current draw decreases with load when hooked up to the stingo. I can also get the coil to sing like I can the car coil. When the circuit is tuned properly it doesn't sing and the motor goes full speed at 600mA compared to 800mA DC.

Here's the video, I also measure the pulses with my little scope which is great to watch.

YouTube - Stingo Motor

Congratulation . I am happy that you also get the same result .

Yes, we need a brushed dc motor. A chip controlled fan (brushless motor) like computer fan may work the opposite.

I am gratefull for the replication. You make a better video too .

If you want to experiment try to put a load or neon bulb on the radiant output. Mine can only lit LED though. You may need more complete stingo to do this.

[7imix]

Congratulation . I am happy that you also get the same result .

Yes, we need a brushed dc motor. A chip controlled fan (brushless motor) like computer fan may work the opposite.

I am gratefull for the replication. You make a better video too .

If you want to experiment try to put a load or neon bulb on the radiant output. Mine can only lit LED though. You may need more complete stingo to do this.

Yes, brushless dc motors seem to just run on the stingo without oscillating, so they just draw dc current through the transformers and make heat.

I'm glad you like the replications, they are really fun!

I have put a neon bulb on my 12v stingo and it lights. I also did a mini tesla hairpin which lit a few small neon bulbs. Will do more in this area and post videos.

[sucahyo]

I have put a neon bulb on my 12v stingo and it lights. I also did a mini tesla hairpin which lit a few small neon bulbs. Will do more in this area and post videos.

Thanks, See if it become brighter with load , I will look forward for the video .

[sucahyo]

This is from video that Aaron post on ongoing thread.


Very interesting test. I wonder what happen to stingo if we have shorted, light bulb or battery at radiant part.

Would you interested to make such video 7imix?


BTW, in those video, Peter Lindemann said:
"No Back EMF performance = when you mechanically take the energy out of the motor, it does not draw more electricity."

I wonder what Peter Lindemann comment would be after seeing your video...

[7imix]

This is from video that Aaron post on ongoing thread.


Very interesting test. I wonder what happen to stingo if we have shorted, light bulb or battery at radiant part.

Would you interested to make such video 7imix?


BTW, in those video, Peter Lindemann said:
"No Back EMF performance = when you mechanically take the energy out of the motor, it does not draw more electricity."

I wonder what Peter Lindemann comment would be after seeing your video...

Sure, I'll do some experiments and see what I get.

I am also very interested in replicating the rotary attraction motor. I think I have all the parts I need except for a nice motor. The only thing the motor is used for is the rotating shaft, it looks like. The two magnets are glued to the wheel on the outside of the motor and the motor runs by attracting these magnets to the relay.

One of the problems I see with the stingo motor is that when loading it, it falls out of resonance. It would be nice if the resistance set by the potentiometers were somehow automatically set based on some feedback from the coil, somehow, so that the impulse frequency changed as the motor was loaded and the circuit stayed in resonance, delivering maximum power to the motor.

I wonder how the attraction motor sets the frequency of impulses. I will research this circuit further.