# mechanical rotary gap LRC controller



## few2many (Jun 23, 2009)

Yeah, I was thinking of that because I am way more mechanical than I am electronic. There would be the pattern basically punched out of a rotating disk. The holes would activate an optically triggered relay, like in some distributors. That will only control the frequency. You would still need a means to control the power. You can use the mechanical slider or a different punched pattern in another disk. You would be missing the ease of programming to change it all and fine tune it. It can probably be done and cheaply, but would it be worth it?


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## NintendoKD (Apr 29, 2012)

If it is done right? sure. the idea is that you can achieve high voltage without exotic components, and still have all three legs, with plenty of output.


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## Hollie Maea (Dec 9, 2009)

NintendoKD said:


> I have been trying to think of a way to make a more efficient controller based entirely on mechanical means, as opposed to digital. the battery is used to power an lc circuit, or tesla type system with a mechanical rotary gap. In this way frequency can be controlled by mechanical means. A small D/C motor would be connected, with a potentiometer as the throttle, give it gas and the rotor spins, giving power to a stationary three phase setup. a single gap on the sending end, and three receives at a triangular interval. the faster the rotor spins the higher the frequency. using this design current and voltage can be more finely tuned, higher voltages and lower currents can be used without exotic off the shelf components. as I see it, this design is also deceptively efficient, when tuned correctly, with run capacitors, at appropriate voltages for load. I think that a rotor design like the one mentioned in another post can effectively be used for higher efficiencies, as less slip will be incurred, the relative speed of the rotating magnetic field will be able to sync with the relative speed of the rotor. I think the best way to crack this is to think of a more efficient design.


If you want it to be a decent controller, it needs to have some flavor of vector based control with feedback, which would be probably impossible to implement mechanically. You could maybe make a controller like you are describing using a scalar constant V/Hz control scheme, but V/Hz = K controllers are probably the single most significant reason that people think that AC motors have poor performance.


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## NintendoKD (Apr 29, 2012)

Hollie Maea said:


> If you want it to be a decent controller, it needs to have some flavor of vector based control with feedback, which would be probably impossible to implement mechanically. You could maybe make a controller like you are describing using a scalar constant V/Hz control scheme, but V/Hz = K controllers are probably the single most significant reason that people think that AC motors have poor performance.



Interesting, you gave me something to think about.

thanks,

Nintendo


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## dragonsgate (May 19, 2012)

I think what you are talking about is also called a chopper. That is a pretty antiquated way to go now days. I have heard if you are running below 50 volts it will work fairly well but higher voltage will cause problems. It is a struggle for me to get a grasp on some of the technology available now days but I do know enough to go with the newer stuff. In the long run it saves time and money not to mention being more efficient.


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## Ziggythewiz (May 16, 2010)

With controllers with efficiencies in the 80's and 90's, I don't think there's a whole lot of room for improvement with simpler control.

There are switch controllers which are mechanical, but work in increments and cause severe pack imbalance. As for a potentiometer, that means you're pumping gobs of power into a resistor, not exactly efficient.


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## onegreenev (May 18, 2012)

I am quite sure you could build a decent controller with mechanical equipment but it would be crude compared to what we have today. Why go backwards. It's like going back to the bronze age. Remember the Bronze Age did not go away because we ran out of Bronze. What we have is better than the old clunky mechanical components from years ago. But if you decide to go that route more power to ya! I won't be following that path.


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## NintendoKD (Apr 29, 2012)

dragonsgate said:


> I think what you are talking about is also called a chopper. That is a pretty antiquated way to go now days. I have heard if you are running below 50 volts it will work fairly well but higher voltage will cause problems. It is a struggle for me to get a grasp on some of the technology available now days but I do know enough to go with the newer stuff. In the long run it saves time and money not to mention being more efficient.



this is kind of the way I was thinking, I am just too lazy to build my own controller, and VFD, so I was thinking of an easier way to do itwith off the shelf parts.


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## NintendoKD (Apr 29, 2012)

Ziggythewiz said:


> With controllers with efficiencies in the 80's and 90's, I don't think there's a whole lot of room for improvement with simpler control.
> 
> There are switch controllers which are mechanical, but work in increments and cause severe pack imbalance. As for a potentiometer, that means you're pumping gobs of power into a resistor, not exactly efficient.


to drive a small low power motor in order to rotate the gap rotor. but I get what you are saying. I am not bashing new controllers, I just want to explore other options. Besides, who wouldn't want a real "tesla" powered EV??? I ask you who?


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## NintendoKD (Apr 29, 2012)

dragonsgate said:


> I think what you are talking about is also called a chopper. That is a pretty antiquated way to go now days. I have heard if you are running below 50 volts it will work fairly well but higher voltage will cause problems. It is a struggle for me to get a grasp on some of the technology available now days but I do know enough to go with the newer stuff. In the long run it saves time and money not to mention being more efficient.


you and I are talking about two totally different things here.


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## dragonsgate (May 19, 2012)

I am ready to be enlightened. What is the difference? I am not being snide. I would really be interested in knowing. However even in my ignorance of which is what I still think either one would be a step backwards. Protecting my butt here I will add that there is nothing wrong with going ahead with the project to sate your curiosity.


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## NintendoKD (Apr 29, 2012)

To be perfectly honest, I AM sure of what you are talking about, however, I am not positive of what the name of what I am talking about is called. I have only heard of this called a rotary gap. A disc with a single contact, right after the cap tank. the other side is a non rotating disc, however, this can be done in reverse, where the single contact is stationary and the three recieving contacts are rotating. or in varying order, ex. vice versa. the idea is that the rotating disc is controlled by a small motor, and by controlling the motors speed you can controll the frequency at which the recieving coils get their power. you can use this to go from 0hz to the limits of the motor, and a varying degree of advance, due to the limit of the surface area of the contacts, similar in design to a distributor. I must also add that I am not the best with words. I have a fairly difficult time getting what is inside of my head onto paper either drawn or written, It is frustrating to say the least. I apologize if I offended anyone, my object is not to be hostile.


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## Tesseract (Sep 27, 2008)

Do less typing and more searching:

Mechanical controller thread #1

Mechanical controller thread #2

Mechanical controller thread #3

Mechanical controller thread #4


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## dragonsgate (May 19, 2012)

Here is sort of what I remember about the chopper / speed control. The idea was to take a starter motor and gut the windings and attach some of the bars from the com to copper strips attached to the armature. Then attach a 12 volt electric motor to the modified starter motor using the original brushes and housing. This is not my design so from here I am lost. In the 80’s Mother Earth sold plans for a hybrid electric car. I bought a set and never did anything but look at them a few times and then stash them away. I know they are still around somewhere. If I find them I will give some more info it you want but I remember the plans and directions as being a little vague.


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## dragonsgate (May 19, 2012)

I found the plans. If anyone is interested I will share some more about them. It is an interesting contraption for the time but way out dated now.


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## few2many (Jun 23, 2009)

Whats amazing to me, Is how much I am seeing 3phase vfds in everyday equipment! Ice makers, fan motors, ac units and even large Ice dispensers, all have little 220v single phase, to 3phase vfds.


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## NintendoKD (Apr 29, 2012)

Tesseract said:


> Do less typing and more searching:
> 
> Mechanical controller thread #1
> 
> ...



that one is a big DUH! yeah, probably should have tried the search feature first, thanks tess.


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## Woodsmith (Jun 5, 2008)

I had a go at making one.


I wouldn't use it, except for a bit of fun.

One snag is that if the controller drive motor failed then the controller itself can fail in one of two modes, fully off or fully on and there is no way of determining where it will stop.


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## onegreenev (May 18, 2012)

Why do something that is old and will give you marginal results. It will be a major undertaking to reproduce that sort of thing. It is not as simple as one might expect. Spend your time elsewhere that will really do some good.


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## dragonsgate (May 19, 2012)

Leave it to Woodsmith to have done it. Art for arts sake right Woody?


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## NintendoKD (Apr 29, 2012)

did you ever throw spitballs in class? I did I got in trouble, and it served no purpose, but it sure was fun.


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