Electric Motor Secrets

[Donald Haas]

Best silicon steel

Hi All,
In the past I tried out the concept starting with a series wound winch motor.

Now I want to order some laser cut laminations and I need advice regarding best type of silicon steel for the "X" rotor version of the motor.

There is a local laser service co. but would probably have to order the steel.
Also thickness is another question.

I suspect that this thread will pick up business again with PL's latest demo of
Benitez tech.

Thanks for your help,
bro d

[mbrownn]

If you check out these people here:

https://www.physics.wisc.edu/instructional/phys109/fourier-java5/

it looks as if your curve is approximately a fundamental sine wave with the addition of the third harmonic.

Whether this gets you anywhere is, of course, quite a different matter.

I think your right. however I dont think that was the case with Bedini's generator.

Maybe looking for a harmonic may be a way of using resonance when you cant reach the resonant frequency of a coil.

[wrtner]

Hi Mbrown.

I decided to ignore the collapsing spikes and am no longer collecting the generator function.
I ran the motor at 140volts and it went to 3362 rpm with only 0.18 amp
or 25.2 watts. It does have a lot of torque.(not measured, just felt)
Look at the position of the driving pulse.
Here are some scope shots.

Robert

If you check out these people here:

https://www.physics.wisc.edu/instructional/phys109/fourier-java5/

it looks as if your curve is approximately a fundamental sine wave with the addition of the third harmonic.

Whether this gets you anywhere is, of course, quite a different matter.

[Robert49]

Jim Murray's Torroid motor

Hi friends,
I'm currently working on this torroid motor. Three years ago, I made a very crude torroid motor just to see if the idea made any sense and it worked.
The electronic controller I made was not efficient and could not operate at high speeds.
The controller for this new motor will use shift registers and position sensors, and a pulse generator. No details yet as it's all in my head for now.
I have most of the parts done on the motor and my friend will machine the rest as soon as he has time.

Be back for more.
Robert

[Listener192]

The attached DC motor tutorial is a little more complete than those found in many text books. Extract follows...


The I2R term represents heat dissipated in the armature, but the very important term EoI is the electrical power that is converted into mechanical power. The mechanical power of the motor is therefore exactly equal to the product of the cemf multiplied by the armature current

P = EoI (5.5)


where

P = mechanical power developed by the motor [W]
Eo = induced voltage in the armature (cemf) [V]
/ = total current supplied to the armature [A]

So if you reduce CEMF, then your mechanical power output, at full speed will decrease.

[Mario]

Question for P.Lindemann

Hi Peter,

I have watched your very interesting videos. I have a question about the switched reluctance motor tests you show in the demo video (https://www.youtube.com/watch?v=DuZ3...Y&spfreload=10).

When you brake the motor the current goes down. I understand the BEMF principles. But how can the current decrease with reduced speed? I mean, the frequency gets lower, the coil inductance decreases and the pulse width gets wider because the reed stays closed longer, meaning more current. Or does the pulse width stay constant for some reason in this setup?

regards,
Mario

[Robert49]

Thanks Gyula

Robert

[gyula]

Hi Robert,

I wish you a quick and safe recovery.

Take care.

Gyula

[Robert49]

Hi.
Sorry I've been gone so long and won't be back for a while.
Just got out of the hospital but still on intravenous antibiotics at home for
six more weeks.

Nothing new for my experiments.


Robert

[voltan]

smee again.2 posts ago,when you say the effect is gone,do you mean no power at the fwbr.if so it would suggest,if not confirm all of the spike energy is looping back to the power supply through the regular diode in the ixfhs.(the way your coil chains are connected to + is perfect for looping to the input), but if your after output or max output that path has to be blocked. i haven't had much experience with fets but i would assume a diode between ground and source would cure this,but there may be implications or anomalies with the fets that i'm not aware of. if they're ok with this then the revised collection scheme in my last pic would be worth a try .
aweful drag as you mention,as discussed here recently,is likely a mix of transformer/motor/generator functions,(changing magnetic fields -current flow in the off coil-lenz effect-etc),as opposed to just collecting the spike energy(buggerall drag).so far it's better to collect off each coil chain individually,and preferably both for max output for now.down the track if you can get real OU you might be able to loop 1 coil chain,for a self runner and draw power off the other.nice setup for trying different combinations.
i'm not a fan of fwbrs as you cop diode losses twice.am a big fan of 1n5189s but they are only rated to 40v.my next pick would be fr302s.starting to waffle now.
stick with it.history has shown that imagination and dedication lead to breakthroughs. cheers

[Robert49]

hi robert.it might be worth trying this on both fets.either take power off the caps or let em fill up to the point when they hardly conduct and take power off somewhere else,maybe try the fwbr with one ac leg connected to each drain .cheers.

Hi.
I have tried connecting one ac leg to each mosfet drain and the drag is awfull.
I am now building a circuit to control where on the mwm wave I take off power and also how long I take it. One 555 for delaying and one for the duration of the pulse.

Thanks for your input,

Robert

[Robert49]

Hi Robert,

I can "assure" you that your ixfh20n60 type also has a diode across its source and drain... in fact every power MOSFET has this so-called body diode, created by the manufacturing process, unfortunately.
See the data sheet for ixfh20n60: http://ixdev.ixys.com/DataSheet/91526.pdf

The 12n50c3 type has 'only' 500V drain source breakdown voltage and 12A drain current versus the 600V, 20A ixys type and their Rds on resistance is similar. Of course a 600V breakdown voltage device is "100V safer" to use in inductive switching circuits than the 500V device.
But the mere use of the 12n50c3 type did not likely cause the measurement errors, and the use of low pass filters would still be a good method for cleaning up the DC supply, both at the front of the input and at the output of your motor setup (your motor's output, when rectified and filtered, becomes a DC supply).

So what is the correct DC input current draw with the cap and 200W lamp loads I wonder.

Thanks for your kind efforts and sharing,
Gyula

Hi Gyula

I know about the diode in all mosfet but the difference is with the zener diode of the 12n50c3 and the regular diode of the ixfh20n60.
I have changed the mosfet and the effect is completely gone.
But I will not give up. Some people have been at it for 30 years. This is only my sixth motor and I am getting better,... I hope.

Thanks for the good words.

Robert

[voltan]

hi robert.it might be worth trying this on both fets or maybe try the fwbr with one ac leg connected to each drain.or maybe not.
with the collection scheme in the pic the load voltage won't go much lower than the supply voltage because switch-on would pull it up to match and when it's running the nature of the load and it's impedance might have some influence on the circuit. cheers.

[gyula]

Hi Robert,

I can "assure" you that your ixfh20n60 type also has a diode across its source and drain... in fact every power MOSFET has this so-called body diode, created by the manufacturing process, unfortunately.
See the data sheet for ixfh20n60: http://ixdev.ixys.com/DataSheet/91526.pdf

The 12n50c3 type has 'only' 500V drain source breakdown voltage and 12A drain current versus the 600V, 20A ixys type and their Rds on resistance is similar. Of course a 600V breakdown voltage device is "100V safer" to use in inductive switching circuits than the 500V device.
But the mere use of the 12n50c3 type did not likely cause the measurement errors, and the use of low pass filters would still be a good method for cleaning up the DC supply, both at the front of the input and at the output of your motor setup (your motor's output, when rectified and filtered, becomes a DC supply).

So what is the correct DC input current draw with the cap and 200W lamp loads I wonder.

Thanks for your kind efforts and sharing,
Gyula

[Robert49]

oops

Voltan and Gyula

Thanks for waking me up.

I put an ac amp meter on the input from the variac and you are right.

I use ixfh20n60 mosfets for my motors and I have a box of those but the box contained something else. There was a mix-up. There were some 12n50c3 in there and I never checked the part number since the box said ixfh20n60.

12n50c3 has a zener diode from source to drain !!!
So now, I'm back to reality but I still have hopes for this and will tinker with the timing and see what happens. ( and will clean that box )

Thanks a lot

Robert