Electric Motor Secrets

[Vincevl]

Having some troubles with my rotary attraction motor

Hi All,

I'm having some problems with my rotary attraction motor circuit. When I power the motor directly from the power supply the rotor is attracted quite powerfully to the armature. I have a phototransistor switch set up that trips a FET that is supposed to delivery the 12V needed to drive the motor. However at most I am only getting 3-4V. I'm not an electronics person so I could use some help in this circuit.

You can watch this video to see the problem Rotary Attraction Motor - Lindemann - YouTube

Many thanks,
Vince

[Harvey]

Hi Vince,

Your MOSFET is triggered by a gate voltage that must be several volts above its source voltage.

From what I can see, when you try to turn on the transistor the source voltage raises up to about 4 volts which diminishes the differential between it (the source) and the gate.

Let us try and rewire it so that it is switching the ground side instead.

Supply (+) >> Coil High Side >> Coil >> Coil Low Side >> Mosfet Drain >> MOSFET >> Mosfet Source >> Supply (-)

Then your 9V (-) should also be tied to the supply (-) as reference.

Now when your photo transistor supplies the gate with a signal, it will always be relative to Supply (-) and the MOSFET will turn on completely (with about 8 to 10 volts). A gate to source voltage of only 7V will never reach much more than 4.8A with a 10V supply according to the charts:http://www.radiotechnika.hu/images/IRF510.pdf

Rewiring it as stated should solve your problem.

[Robert49]

Hi Robert,

It could be that the peak current is too great for the transistor rating.

Also, the transistor may not support repetitive avalanche.

One thing you may wish to incorporate is a means to dump the BEMF into the next inductor sequence - in other words, capture the BEMF with diodes routed to the opposite rotor coils such that as the fields collapse on one rotor, the energy is routed to power the other rotor.

One way to control the peak voltage of the spike is to widen its discharge time. Very narrow discharge times result in high voltage spikes. The faster a transistor "turns off", the higher the spike can be. Of course lingering the on time can have the negative effect of back attraction.

You may wish to wave shape the gate signal so that it turns off earlier, but the trailing edge is a bit sloped. A word of caution here is that while that will help reduce the HV spikes, it will increase the heat in the transistor because it tends to operate as a resistor for a longer period. It is for that reason that most MOSFETS (if you are using a MOSFET) are switched as fast as possible.

If you are willing to share a schematic, it may show up some areas that can be improved on.

Cheers,

Harvey

Hi Harvey
I found the source of my problem!
My ground wire for the 555 and the one for my fets were too close and
causing induction with each other. So I made the two circuits separate
and I used opto isolators and shielded wire to connect them.
Now the motor runs smoothly at 750 rpm.
There's still a lot to be done.
I'm on vacation in florida so I will get back to it in a month.

Robert

[Harvey]

Hi Robert,

That is good news

I'm not a fan of wave shaping to get the spikes down - but when we are experimenting sometimes it can help isolate the problem - at least if that was the cause of the failures it could keep things running long enough to pin down the cause.

I'm glad that you were able to spot the feedback and get things separated out.

Cheers!

[Robert49]

My new rotary attraction motor.
Special thanks to Tom Bearden, John Bedini, Peter Lindemann, Joseph Newman, the late Bruce DePalma and all the others for the inspiration.

3 sets of 4 coils in series connected n-s-n-s.
Timing wheel and timing ajustment ring all integrated.
At 50v runs on 550ma at 4000 rpm. No heat.
At 160v runs on 1amp at 12000 rpm. Only heat from bearing friction.
The spikes from collapsing fields are over 3000 volt.

By the way, this is a modified dishwasher motor 1700 rpm at 1.4 amp.

Pictures moved to page 52

[Jetijs]

Hi Robert, that looks impressive!
Thank you for sharing
Jetijs

[Robert49]

Hi Robert, that looks impressive!
Thank you for sharing
Jetijs

Hi Jetijs.
I love to experiment.
My earliest motor was a magnet motor generator that used 300 watts input at 120 volts and gave me back just the same while running at 6500 rpm with quite a bit of torque.
Unfortunatly it exploded because i used plexyglass for the rotor.

This new motor is part of a motor-generator based on the n-machine or Faraday disk.
I will post the results as soon as I have them.


Robert

[Harvey]

Nice Work Robert

I wonder how this new motor specs out on Braking HP and Torque to power consumption ratios

Thanks for sharing your research

[Robert49]

Nice Work Robert

I wonder how this new motor specs out on Braking HP and Torque to power consumption ratios

Thanks for sharing your research

Thanks Harvey.
I will do the braking test eventually and report on it.
But I tryed something crazy with my attraction motor.
I connected a 96,000uf cap and a 24v rated 10.5a 180w at 2500rpm motor on the output .
When I run my motor at 150v 1a (6500rpm),the 24 volt motor runs at 3100rpm and when I put a load on my motor, the 24v motor accelerates.(more energy coming out).
Then if I put some load on the 24v motor, it discharges the cap and slowes down (amp draw rises because of counter EMF), but no change on my attr motor.

I tryed the same except this time I put my big rotary attraction motor instead of the 24v motor.
The difference is that when I put a load on my big rotary attraction motor, it slows down, the amps go down and the voltage on my cap rises.
No change on the smaller rotary attraction motor .

Fun to experiment.

Robert

[Blargus]

That looks awesome robert49 ! If you don't mind can I ask what modifications you did to the motor besides the timing wheel? Great video, Electric Motor Secrets, I don't have much electronics experience and I could follow along pretty well!

[Robert49]

That looks awesome robert49 ! If you don't mind can I ask what modifications you did to the motor besides the timing wheel? Great video, Electric Motor Secrets, I don't have much electronics experience and I could follow along pretty well!

Hi Blargus!
Well I removed all the wires on the stator and re-wired with bigger gauge and if you look at my previous pictures, you'll see that I now have three sets of 4 coils in series connected "north-south-north-south" (more powerfull than with same poles) driven by 12 pulses per rotation.
The rotor is also modified from round to a cross shape.

The spikes coming out of this motor are over 3000 volts when driven at 173 volts. The motor now runs at 12000 rpm at this voltage and I run a 180watt 24volt motor at 6000 rpm on the energy coming out of it.
The rotary attraction motor and the bearings stay cool even at that speed.

Hope this helps.

Fun to experiment!
Robert

[Blargus]

Thanks robert, yes it does help! Very cool. Would like to do something like it but I think I need more electronics education first. What type of motor already has the iron core, is that a squirrel cage type A/C motor? And also when are you going to put it all back into the dishwasher?

[chainmailleman]

Bifilar coils

Bifilar coils, their strength vs normal coils, and series and parallel configurations.

The wire is a resistor. Assuming the length of the windings is the same in a bifilar coil, when hooked up in parallel the resistance of the wire is DIVIDED by 2 (2 resistors in parallel is half the rating), when hooked in series the resistance of the wire is DOUBLED (2 resistors in series is doubled resistance). When the bifilar coil is hooked up in series, the power draw is 1/4 of that in parallel.

A video by username: Jupy921 on youtube demonstrates this concept. It can be found at this link: Bifilar coil's magnetic field strength vs. a normal coil's field - YouTube (I am froddofromtheshire).

If you do the math you will find a parallel wound parallel connected coil is 8 times stronger per watt than a single strand coil for the same number of turns. A parallel wound, series connected coil is 62.5 times stronger than the parallel connected coil. The series connected coil is 500 times stronger than a single strand coil for the same number of turns.

The voltage between the turns is just as important as the amps per turn as found by the formula (volts/turns) X (amps/turns) = actual power or stored energy in the coil. You can also find the same number by total magnetization X total power applied to the coil. (total magnetization is found by magnetization/time = voltage)

In summary: the parallel wound series connected bifilar coil produces more magnetic field PER WATT than a single wound coil, or a parallel wound parallel connected coil.

Connect your bifilar coils in series for a stronger field strength for a lower applied power in watts.

[Donald Haas]

Junior member

Hard to imagine what we will be expected to bear when Rick becomes a Senior member.

Ignorance and arrogance are eternally ugly.

Your Brother in Christ!

Edit:

I posted the first part after reading Rick F's bashing of Dr Peter, early in this thread.
Rick has a long history of over the top egotism and non Christian behavior.
He told me personally that his christian ministry was more important to him than
his other activities. I have bitten my tongue for years when his behavior is very wrong.
This time I failed.

I've built many devices for about 10 years and I've just finished going through this thread and planning to build "one".

I've been reading today at this site for about 10 hours and and I'm very grateful for the guys, and Grace that are posting.

Keepin' on,

donald

[Donald Haas]

Smc

Hi All,
Read this on the web by a UK professer.

Good for me to consider.

"Normally, motor is made from lamination sheets which are punched into desired dimension and shape. Each lamination sheet allows the magnetic flux to flow on its 2D plane and this effectively creates a 2D flux path. There is another type of soft magnetic material available in the form of coated powder iron. This material is known as dielectromagnetics or soft magnetic composite (SMC). When SMC material is used to make an electric motor, the material is pressed at high pressure in a die which resemble the shape of the motor. The motor produced using SMC material have isotropic characteristic which enable the distribution of magnetic flux in 3D.
The concept of 3D flux path SR motor is shown in Figure 12. By using SMC material, the flux path is no longer restricted to the plane since SMC exhibits isotropic characteristic. The new 3D flux path is shown by the dotted line in Figure 12. The 3D flux path is effectively shorter than the flux path in a lamination sheet. This has several advantages and in term of the magnetic circuit of the motor, less MMF is required to energise the motor due to the shorter flux path."