Electric Motor Secrets

[StevanC]

I'm actually not surptised at all - contrary i know that the preferred device are the voltage driven ones.

You are most right that the MOSFETs and IGBTs provide a handfull of advantages ar rough power stages etc. AFAIK

I agree with that.

I only wanted to point out that there might be scenarios where thet 'insignificant additon' of drive current to power handling, might be all what's needed?

Think 'delicate tipover'?

thi topis tends to borderstep this topic, and i had no intention to taint it, just to make a point above?

[nali2001]

For all of you who want to experiment with the attraction motor concept. I might have found something interesting. Here they sell for $89.95 commercial reluctance motors of "close to 1hp" it even comes with controller (which you probably won't need.)

Anyway it is a surplus store and they have only 9 sets in stock. So I'd say go for it since I have never seen affordable reluctance motors before.

M132-013A001-16B & Controller-Switched Reluctance Motor & Controller-Electronic Surplus Inc.Offering obsolete IC's, discretes, motors, relays, switches, pots, and much, much more! Always looking for your excess inventory.

-edit-
Oh, they also have 'motor only' sets - 10 of them left:
M132-013A001-16B Motor Only-Switched Reluctance Motor 2-Phase-Electronic Surplus Inc.Offering obsolete IC's, discretes, motors, relays, switches, pots, and much, much more! Always looking for your excess inventory.

Regards,
Steven

[Mark]

Its Time For An Update Jetijs

Okay its been 2 weeks now Jetijs I think you owe us an explanation! I dont see any data on your motor, no amp draw, no HP, nothing. Ok enough harping! Whats going on? Is it sweet or what? Please give us an update.

When you figure out a way to check horse power I'd be very interested in what kind of HP you get out of your Tesla Air Turbine also, and at what air pressure.

Keep up the good work and look forward to hearing from you!

Mark

[Jetijs]

Steven, I wonder what the air gap of those motors is. Do you know? Anyway, looks good enough and cheap for enthusiasts to play. Also, what are the rotor/stator pole count?

Mark,
still waiting on my shaft coupler.

[Mark]

Just use a piece of fuel injection hose and some hose clamps.

[Jetijs]

Mark, I want it to be perfect. I have experience with all kind of couplings used on my homemade cnc machines, the lovejoy couplers work best so far. A hose with two clamps is not an option. Also I will take a week off, I need a serious rest for a while
Thanks,
Jetijs

[Mark]

I know, I would expect nothing less. Just giving you a hard time and trying to mess with ya!

[Jetijs]

And you are doing a great job at it

[Jetijs]

Hi all
Today I did some experimenting with one of the V3.0 motors. The circuit I used was like this:



With both phases running, the motor revs up to about 10000 RPM at 12v input voltage. I noticed, that I have my recovery didoes wired wrong so I fixed that, because before there was no recovery at all. At first I attached the output of the recovery to a 40Ah lead acid battery to see if it would climb up. When I started the motor, the battery started to go up, but not as fast as it does with my Bedini selfoscillator at about the same input current. Then I put the recovery to the input capacitor of the circuit board. I noticed, that the motor started to run faster, a bit quieter and the current consumption went down, but just a little - it went down from 6.1A to 5.5A. I expected better results. Then I switched the 1N5408 diodes to UF5408, those are 75nS diodes. This gave no improvement.

Also I found out that when the motor is running and I am adjusting the timing, as I set the timing for higher speed, the current consumption also increases. So higher speed - more current, but this is only in the timing adjusting phase. If I set the timing solid and the speed increases due to the bearing warm up, the current is going down as the speed increases.

Another thing about the timing is that the optoswitches have 20uS rise/fall times. This means that I need to adjust the timing at higher speeds to get the optimum timing (max speed). If I use the same (high speed) timing to start the motor, it at first has a little hard time to rev up, but after then it goes smoothly.
The motor is stable at 11k RPM and vibrates just a tinny little bit. I used four 1n5408 diodes in parallel as the isolation diode for higher current capability (12A) and they get quite hot even if I use just 7A, but I guess that this is not a big problem.

That's it for now.
Any comments, suggestions?
Thanks,
Jetijs

[LowTechIsCool]

Good Job

Jetijs,

Hooked it up and was able to go 10k+ rpm!!! amazing. It seems to me that a natural application for this would be to hook it up to your Tesla Turbine. Have you designed your devices to connect?

How do the zener diodes placed back to back near the mosFET work? If you get too much voltage, does it reverse bias and acts as a voltage regulator? Are you supposed to operate the mosFET in the triode region or in saturation?

With Gratitude,
Chris Corkum

[lighty]

How do the zener diodes placed back to back near the mosFET work?

Those are not Zener diodes but ultrafast (in the ps) protection diodes (google transil diodes).

Are you supposed to operate the mosFET in the triode region or in saturation?

Since MOSFETs are used as switches they must be fully saturated as fast as possible in order to reduce power dissipation and loses of the linear region.

[uusedman]

my switch reluntance motor just arrived. I going to start hacking away. will post something later.

[Jetijs]

be sure to make a lot of pictures

[LowTechIsCool]

package in mail

LOL. Got my switched reluctance motor today too.

[uusedman]

It is alive. YouTube - uusedman's Channel. I posted basic modifications of the rotary attraction motor. It is not running 10,000 Rpm, but it is a running and that is a start .

now, i have to add some other stator and more DC pulse points to get this motor flying.