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creating hard "off" when voltage rises above certain limit.

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by qwerty68, Mar 2, 2011.

  1. qwerty68

    qwerty68 New Member

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    Hello, This is my first post at this forum I hope you can help me out.
    I am searching for a way how to design a circuit doing the following:

    I have an electromotor of which I want to limit the rpm.
    Attached is a dc power supply that, is soon as 12,3 volts are reached ( the faster the rotor spins the higher the voltage) has to deliver a power off signal.

    With my limited knowledge of circuitry possibilities, a solution with a zenerdiode was the only option I could come up with that came close.

    As soon as 12,3-12,5 volts are reached, the zenerdiode has to reach breakdown voltage.
    This signal I then invert using a 7414 schmitt inverter and then I have my power off signal.
    As the voltage drops below the 12,-3-12,5 volts, the zenerdiode blocks the current and the 7414 inverts it into an "on" signal.

    The problem with zeners is that they have a tolerance and might not be that accurate.

    How can I solve this? Or are there other, better possibilities to get a hard off at the required voltage?
     
  2. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    To limit RPM I would monitor the RPM rather then the voltage feeding the motor.
     
  3. qwerty68

    qwerty68 New Member

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    That was my first idea as well. I had no clue however how to translate an rpm signal into the off-on I need.
    Also, I could not find a receiver in a hardware store other then an rpm gauge to use the internals from.
    I could connect two wires and use it as variable resistor but I couldn't come up with a way to translate that to the off-on.
     
  4. dave

    Dave New Member

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  5. OlPhart

    OlPhart Member

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    Off the top: disc on motor triggers opto coupler. Opto coupler pulses feed a counter. Tunable oscillator resets counter Just before overflow, at all rpm below signal speed. At signal speed, counter overflow is a pulse train at oscillator pace, latch/release & process as required. A simple discrete circuit.

    However, to Really control rpm: a uC (microcontroller) counts the time between opto coupler pulses and adjusts the PWM that powers the motor. Maybe start at 100% duty cycle & roll it back from there as approaching desired speed. It's total control of motor behavior. A sufficiently fast monitor loop will keep rpm stable under varying load. A closed loop servo system.
    I'm now out of fish... <<<)))
     
    Last edited: Mar 2, 2011
  6. BrownOut

    BrownOut Banned

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    You just need to create a voltage reference at 12.3V, and use a comparator to output the stop pulse. As accurate reference can be created with a voltage regulator, and of course, an input voltage.

    BTW, how does the voltage that increases with RPM get generated?
     
    Last edited: Mar 2, 2011
  7. qwerty68

    qwerty68 New Member

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    the second method sounds a bit more doable for an electronics beginner.
    After a bit of research it seems that a comparator is an opamp.
    I also read that there is a danger, when the voltages get close that some distortion might occur?

    tricky is that I don't have a steady voltage. the voltage is directly related to the revs of the rotor with an attached generator.
    When the voltage drops below a to be determined value however, say 11,5V, the power will shut down completely and no on-off will be needed anymore so if there exists the possibility of rectifying a voltage in the range of 11,5v-12v to a steady 12,3v, it will be ok.
    Instead of 12,3V I could apply a lower voltage by putting resistors of the same value before the opamp inputs I presume, 12,3V as a reference might be to high.

    The power gets generated by converting the output of a 220V AC generator to 12v DC.
    A motor drives the generator which has to come up with a steady output between 220 and 230V.
    This is what the rpm control is going to be used for.
     
    Last edited: Mar 2, 2011
  8. BrownOut

    BrownOut Banned

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    Your reference can't be the same as the supply for the comparator. You will need a lower voltage regulator, and a voltage divider on the output of the generator to produce a voltage for comparason.
     
  9. qwerty68

    qwerty68 New Member

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    now it gets complicated after all, for me that is after a few a bit non patient days of reading into stuff that's quite new.
    The separate parts I understand, but designing a working circuit of this with the necessary components is a headache generating process.
    I hope that you can be of some assistance with this.

    I must say I am also attracted to the micro-controller option suggested bu Olphart but parts and circuitry....:confused:
     
  10. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    What sort of beast is this thing ?
     
  11. BrownOut

    BrownOut Banned

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    What voltage does the motor run on? You could use that supply for your comparator. Maybe it's high enough you won't need to divide the generator output.
     
  12. qwerty68

    qwerty68 New Member

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    to be honest I tried to avoid a precise description on what I am working on to prevent this topic going into the arguing and possible debunk of the project.

    But here it is, it's a free energy motor generator project driven by the Steorn principle.
    The motor will be of my design, the generator is just an ordinary one taken out of a petrol engine driven 220v power supply.
    I live in Europe, 220-230V is required here.

    I read the post of the Victim and, as many other people having a hard time getting around how it all works, it seemed wise just to stay to the point.

    The problem with understanding free energy is that the whole idea behind it is totally misunderstood, I'll try to explain.

    Many presume that free energy comes out of nothing, resulting in overunity devices.
    This is the misunderstanding.
    Free energy is about one thing only: to invite the energy of an external energy source into the process, whether this is wind, solar radiation, magnetism, gravity, cohesion, chemical or more unknown sources as zero point energy or orgone.
    Windmills, sail boats and solar panels are perfect examples as are your car and motorcycle believe it or not.
    The last two use an external chemical energy source called petrol. When you keep pouring it in, your engine will keep going on forever.

    Many examples seem to have the power input of zero point energy. This seems hocus pocus energy but in fact was already mentioned by Einstein and forms the basic energy in the quantum world.
    The only way it manifests itself is when one energy source is transformed into another.
    Because there is no way to measure it and we don't have the senses to feel it nor does it affect us the way gamma or x-ray radiation does it seems to come out of nothing.

    The Steorn principle however is just mainstream science.
    It is about a clever way to eliminate Back EMF and to shield the permanent magnetic energy field.
    The rotor then is sailing on magnet power.

    The shielding of the permanent magnetic field is done by coiling ferrite cores on the stators, the back EMF is eliminated by having the stator cores approach by a north and south poled magnet as a pair, mounted in the rotor.
    The stator coils thus produce neither a south field nor a north field resulting in zero EMF if timed and positioned all right.
    On approach of the rotor magnets the coil power supply is of, when the rotor magnets are exactly above the coils, the power is turned on, annihilating magnetic backdraft.

    An example of how magnet shielding works, using only battery power is demonstrated here:
    YouTube - Understanding the Steorn's effect : a basic experiment

    An example of how to eliminate the back EMF by letting a north and south oriented magnet simultaneously pass a coil exactly over the coil-mid is shown here:
    YouTube - Steorn motor V3: Canceling the Back EMF, How To ?

    A perfect working amateur Steorn model using only 9V, 0,2A input is shown here:
    YouTube - Canal de mschuckel

    The power output is theoretically unlimited if you put enough disks with enough magnets in line.

    So to answer BrownOut's question, the input in my case is 12V DC current, during the start-up process delivered by a motorcycle battery, and when a the required speed is reached, taken over by a 12V power supply, converted from the 220V delivered by the generator.
     
  13. Mr RB

    Mr RB Well-Known Member

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    Hasn't the department of business affairs shut those crooks down yet?

    Last I heard (after they ripped off investors and failed to produce the "free energy" motor they hyped up in national advertising) they were selling $600 kits so people could investigate "solid state free energy" on a little PCB, no kidding.

    I'm sorry qwerty68 if you didn't want to hear that. Steorn had their chance to demonstrate the "free energy motor" to independent evaluation and the independents all said it was bunkum.

    Of course, if you know more than the independent experts please speak up.
     
  14. BrownOut

    BrownOut Banned

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    Doubt I will be able to help with that.
     
  15. qwerty68

    qwerty68 New Member

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    It doesn't matter what I read or heard, just stories, it does matter what I see.
    Simply look at the youtube video's I referred to and reed the simple technology behind it.
    This proves that it works and these are just a few examples. I can come up with maybe twenty or more clips all with perfectly working home built steorn devices.
    The skepcism has me quite puzzled.
    I've done some very primitive first tests a few days ago and it works.

    So I don't know how or why steorn supposedly messed up at their presentation or what the reason is this that people who where there say it fails.
    Something blocks Steorn from selling their technology and they have no other choice then selling their investigative results.

    Just look it the video's at mschuckels channel and for instance this one with the entire development process of a Steorn project covered.
    The Steorn Orbo motor replication by JL Naudin
    Trust your eyes, not the stories.

    This is exactly what I tried to avoid, and I've read all the negative publication so I've heard and seen them all. It makes me bit sad.
    I notice that too many believe the written publications and refuse to see that it does work. The links I provide speak for themselves.
    No offense.;)

    And what I know... just read this. A good summary of many free energy inventions with a lot of background information:
    http://www.free-energy-info.co.uk/PJKbook.pdf

    Now, this is getting off topic and I would like to pick up the red line of this post.
    I am not here to debate the project, just to get some advice how to handle electronics.
    Whether the project works or not will be my problem, isn't it guys.

    A Uc microcontroller as I researched is above my league, I would like to stick to the comparator.
    As a stable 12v power source I could use a 12v adapter plugged into the wall socket although I would like to avoid that.
    About a rectifier: does it come up with a stable output voltage as the input is not stable though within margins?

    I very much hope that you are prepared to respect my choice trying to develop this, and assist me with my elecronic issue.
     
  16. BrownOut

    BrownOut Banned

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    A 12V adapter would be a good choice. No need for a rectifier, the 12V adapter is already 12VDC.
     
  17. qwerty68

    qwerty68 New Member

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    yes, the adapter is the most convenient option.
    The reason for having a 12v system on board is to serve as backup in case the adapter breaks down.
    I must say that I feel challenged to run it independent from the adapter in time.
    Every fuel engine driven home generator does it that way. The electronics involved might be to much for now.

    About the comparator.
    Is it just a matter of connecting steady 12v and rpm dependent dc delivering an output of '1' or '0'?
    I almost can't believe it's that easy.

    The rest of the electronic management is covered by the way, this was the remaing one.
     
  18. qwerty68

    qwerty68 New Member

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    This is my last post for today by the way, it's getting close to midnight here.
    Thanks for all the help.
     
  19. bryan1

    bryan1 Well-Known Member

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    Well not to detract from your project and I did have a decent read of that link you provided.

    4mW in 23mW out, so just how many $$$$$$ has been spent just to dis prove the physics laws and I reckon if I made a small axial flux generator and hooked it up to a treadmill with a rat I'll bet I could get more power out than that contraption shown....... So what the input power will be grass which is free and if the rat decides he wants a break just add a little voltage to the wheel and that will get him running.

    If this so called overunity device was SO GOOD don't you think it would be all over the news, instead it has been debunked as a useless waste of time and $$$$. My idea of the rat/treadmill will provide more free power than that contraption any day.........

    If your worried about stray currents maybe one of Bluerooms foil hats will be the answer....
     
  20. Reloadron

    Reloadron Well-Known Member Most Helpful Member

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    I won't try to debunk or otherwise discourage you with your project. Hell, if it makes you happy and you don't get cheated out of money, I say go for it and learn. Lessons learned the hard way are generally lessons that last a lifetime.

    Now looking at this:

    So you need a speed pickup. Some form of speed P/U or a tach generator. The idea being when a certain speed is achieved on the rotating shaft of a motor the power source to the motor is switched. There are several ways to go about it but a Frequency to Voltage converter is a good start. Shaft rotation creates pulses (frequency) which is converted to a voltage level proportional to shaft rotational speed. That voltage if fed to a comparator circuit and compared to a reference voltage. When the signal in voltage exceeds the reference voltage the comparator output toggles. That could be fed to a flip flop circuit so once it changes state it remains there. However, you could also add a little hysteresis to your comparator so when the reference and the signal in toggle the output there is no jitter. You have a few options.

    Personally I see it as chasing pipe dreams but that matters not. If it makes you happy, then go for it. Whatever trips your trigger or spins your generator.

    Ron
     
  21. BrownOut

    BrownOut Banned

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    Not exactly. The comparator will be powered by 12V supplies, and the inputs cannot be the same as the power supplies. You should voltage divide both the reference voltage and the generator output, and that way you'll be comparing correct voltages. Couple 10K resistors for dividers should do it.
     

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