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Author Topic: Pulse motor build off time.  (Read 116772 times)

TinselKoala

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Re: Pulse motor build off time.
« Reply #195 on: December 17, 2014, 08:35:55 AM »
Hey, I thought this was supposed to be fun and educational! But I see it's turning into a testosterone contest. 

Heck, I couldn't even enter any of my amazing, scientifically groundbreaking PMs because I couldn't register on Russ's forum. So I'm just moving on, continuing to do what I do, whatever that is. (Not that any of my recent builds are anywhere near as neat as Tommey's or MCR's.)

Did anyone at all enter anything other than an electromagnetic attraction or repulsion pulse motor? No core effect motors?


Here, laugh along with me:
http://www.youtube.com/watch?v=KHLbQ6zw92w
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ramset

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Re: Pulse motor build off time.
« Reply #196 on: December 17, 2014, 10:56:38 AM »
 next year I think we should ask Russ To add a  a steel cage match to the event ,Spice things up a bit  :o


you seem to have created a space time Vortex or a wee black hole??
It disappeared........


very cool


 thanks


Chet




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MarkE

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Re: Pulse motor build off time.
« Reply #197 on: December 17, 2014, 11:17:33 AM »
Quote from: ramset on December 17, 2014, 10:56:38 AM
next year I think we should ask Russ To add a  a steel cage match to the event ,Spice things up a bit  :o


you seem to have created a space time Vortex or a wee black hole??
It disappeared........


very cool


 thanks


Chet
The RGrieseDome:  Two Pulse Motors Enter, One Pulse Motor Leaves.
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TommeyLeeReed

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Re: Pulse motor build off time.
« Reply #198 on: December 17, 2014, 12:44:10 PM »
Hi All,

I agree this got dirty, but someone wanted to through mud at the beginning.

I am going to Florida for a week where I can relax and enjoy the weather, sorry if I over react like a real man that don't put up with crap.

I think next year should be better rules where one entry per person.

Tom :o





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ramset

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Re: Pulse motor build off time.
« Reply #199 on: December 17, 2014, 01:01:58 PM »

Real Men??
then we shall have Festivus......

https://www.youtube.com/watch?v=dS7-jcsB_WQ


Tom
Have a safe trip to the sunny and warm Southland,and a Merry Christmas .
and a safe and happy Holiday to all.


thx

Chet
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tinman

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Re: Pulse motor build off time.
« Reply #200 on: December 17, 2014, 09:33:38 PM »
Quote from: TinselKoala on December 17, 2014, 08:35:55 AM
Hey, I thought this was supposed to be fun and educational! But I see it's turning into a testosterone contest. 

Heck, I couldn't even enter any of my amazing, scientifically groundbreaking PMs because I couldn't register on Russ's forum. So I'm just moving on, continuing to do what I do, whatever that is. (Not that any of my recent builds are anywhere near as neat as Tommey's or MCR's.)

Did anyone at all enter anything other than an electromagnetic attraction or repulsion pulse motor? No core effect motors?


Here, laugh along with me:
http://www.youtube.com/watch?v=KHLbQ6zw92w
@TK

TK-i would love to see a third coil wound around the center of your containment tube(between the two drive coils),and see what the output looks like on a scope. I think that would be one messed up wave form of no particular pattern lol.
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MileHigh

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Re: Pulse motor build off time.
« Reply #201 on: December 18, 2014, 08:02:16 PM »
Here is another idea for an innovative pulse motor.  Perhaps TK is listening or someone else...   You need to have some electronics and build skills to get this one right.

I will call this pulse motor the "Whacker-Puller."

What you want to do is overcome the slow rise in the current for the drive coil.  So, we know that at TDC the toque from the drive coil is zero.  Let's assume that the maximum torque is at +5 degrees.  So what we want to do is have an "instant on" coil that whacks the rotor magnets when they are at let's say +4 degrees.

You do this with two coils in series in a unique architecture, Coil A and Coil B.  Coil A will be in the regular position for the drive coil.   Coil B will be positioned at let's say +20 degrees.  Coil A will work in repulsion mode, and Coil B will work in attraction mode.

The MOSFET or transistor starts to energize Coil B ONLY, at say -5 degrees.   When the rotor magnet hits +4 degrees, there is current flowing through Coil B, and no current flowing through Coil A.

At +4 degrees, the transistor switches off, and Coil B then conducts current into Coil A.  The current in Coil A rises nearly instantaneously, hence the rotor magnet is "whacked" with the repulsion force from Coil A.

Once the transistor switches off, Coil A and Coil B will have the same amount of current flow, because they are in series.

As the rotor magnet approaches +20 degrees, it is approaching Coil B.  Since current is flowing through Coil B, you have Coil B attract the oncoming rotor magnet.

So as you can see, you have two coils, where Coil B is "pre-charged" while the rotor magnet approaches.  Then Coil B discharges through Coil A, so that you you get an instantaneous "whack" from Coil A and after that you get a pull from Coil B.

One critical thing is that you have to stop all current flow through both coils after the rotor magnet passes TDC for Coil B.  That is a challenge but should be doable.

MileHigh
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TinselKoala

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Re: Pulse motor build off time.
« Reply #202 on: December 18, 2014, 08:32:58 PM »
In my experience, the rise times of current in reasonable pulse motor drive coils is so fast compared to the rotor's rotation that it is for all intents and purposes instantaneous. You can look at the video I posted some while back where I'm showing the Orbette 2.0 toroidal coils applied voltage and current traces on the LeCroy DSO for an example. The current risetime is so fast that the pulse looks nice and square, with the usual overshoots and rings. I doubt if there is as much as one degree of rotor rotation from the "instant" the current is applied, to the time of full current flow, and that's with inductors with highly permeable cores, too. There is a large disparity between the behaviour of mechanical systems and that of electronics! What we consider slow and measurable rise times in pulsed inductors is in practice "instantaneous" when applied to a mechanically moving part with palpable mass. (Tiny reed switches are another story, as we know; a carefully designed mercury wetted reed switch can move pretty darn fast.)

It's a neat idea though. Maybe some pulse motor builder will try it. But it is still an ordinary electromagnetic repulsion-attraction configuration. I still think that designs using the "core effect" are more interesting since they do not rely on electromagnetic attraction/repulsion at all, and they are as rare as hen's teeth.
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MileHigh

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Re: Pulse motor build off time.
« Reply #203 on: December 18, 2014, 08:51:57 PM »
TK:

It's so rare that someone actually puts a current sensing resistor on a pulse motor drive coil that I am not even sure if the rise time is an issue or not.

But that's neither here nor there.  The point is to do something different than the same old boring standard pulse motor architecture.  It poses challenges in design and understanding what is going on, and challenges the builder to actually use their scope to help in the design and verification.  It uses the concept of one coil producing an "instant on" in a second coil.

Even through the design is somewhat complicated, this design or the "Pull-Push" design I proposed before will probably have a decent chance in giving you more RPM per input watt of power compared to a "dumb" traditional design.  Plus you have to work out how to do the triggering, which I haven't touched on.  Just getting the triggering right would be a challenge.

Just something new for the sake of being new.

MileHigh
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TinselKoala

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Re: Pulse motor build off time.
« Reply #204 on: December 18, 2014, 09:39:50 PM »
I agree, something different is all good in the pulse motor realm. And with microprocessors, the triggering wouldn't be all that hard to arrange. I used a 4000 line rotary digital encoder on the Orbette 2.0 during the power dissipation measurements, so timing could be adjusted to the tenth of a degree of rotor rotation using that as position input to the microprocessor.

I thought of another practical example, though. My overhead levitator, controlled by Arduino, using optical shadow-edge sensing, turns the overhead coil off and on through a switched mosfet controlled by a gate drive signal from the Arduino. The levitated object seems "rock-steady", it doesn't have a chance to fall or rise a visibly perceptible amount between pulses (although the shadow sensing system perceives its slight motions). And that coil is a pretty heavy inductor. It's on a top shelf right now and I don't recall the exact inductance but it's one of the larger coils I've wound, larger than any of my pulse motor coils. I think as long as you are pulsing at audio-range (mechanically feasible)  frequencies with a reasonable-sized coil your rise and fall times will be "practically instantaneous" even though they are actually easily measurable and definitely finite on scopes.
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TommeyLReed

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Re: Pulse motor build off time.
« Reply #205 on: December 19, 2014, 02:50:34 PM »
Hello All,

  Tomorrow is the day of 3 winners, I wonder who will be a in that group?

I am in Florida today with the weather around 75deg, really don't want to return to the cold, but my wife said I have to be home before Christmas....

I will be able to watch the Smart scarecrow show tomorrow at 7pm, if I'm one of the winners I will be able to call in.

Stay warm, and enjoy the show.

Merry Christmas to all, including those that I may not agree with.

Tom
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Lakes

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Re: Pulse motor build off time.
« Reply #206 on: December 19, 2014, 03:18:36 PM »
https://www.youtube.com/watch?v=DDt3u2Ev1cI

Merry Christmas Tommy, drive safe! :)
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ramset

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Re: Pulse motor build off time.
« Reply #207 on: December 20, 2014, 11:11:29 AM »
What were the results...??


Thx
Chet
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MarkE

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Re: Pulse motor build off time.
« Reply #208 on: December 20, 2014, 05:29:15 PM »
Quote from: ramset on December 20, 2014, 11:11:29 AM
What were the results...??


Thx
Chet
They have not been announced yet.  There is supposed to be a SSC show to announce the winners.  It may be tonight, but I don't see any dates published.
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Pirate88179

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Re: Pulse motor build off time.
« Reply #209 on: December 20, 2014, 06:47:02 PM »
Quote from: MarkE on December 20, 2014, 05:29:15 PM
They have not been announced yet.  There is supposed to be a SSC show to announce the winners.  It may be tonight, but I don't see any dates published.

I have not seen anything either.  Maybe they are having a lot of trouble deciding?  (I know I would)  Maybe it might take a while for them to figure out who has won?

It will be good to see the SSC back "on the air" as it were.  I always enjoyed Gary's presentations.

Bill
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