Sharing ideas on how to make a more efficent motor using Flyback (MODERATED)

[Magluvin]

I'm going through reed switches like a knife through butter. Current draw down at 10ma on 12VDC. Simplest bloody pulse motor I've ever made. I'm measuring the flyback at several hundred volts though so it's probably that.

Here is a vid back when I bought these 3in reads. Can find on ebay like I did.  They are not as fast at switching as the tiny ones and have resonance issues at higher freq and harmonics around that point. But will work well for what you are working on.

The second vid is showing the pulse motor slowing acceleration when approaching resonance 'points' then accelerating to the next level.

https://www.youtube.com/watch?v=lkxRNhPG2sE

https://www.youtube.com/watch?v=b7PR8JEVp7A      Lol I burn a slot in the tip of my finger accidentally touching the rotor.

The amount the speed jumps isnt from just adjusting.  This also shows bemf being sent to a 5w resistor and gets very hot to touch. I think I say in the vid the ohm. If I remember it was 5?

Mags

[gotoluc]

Hi everyone,

here is the Bucking Reluctance Motor I Designed

Link to video: https://www.youtube.com/watch?v=WL3kO4n2XsE

If someone can help confirm if CEMF or Lenz is negated in my test or suggest a test that would be appreciated.

Thanks

Luc

[Ed morbus]

Thanks for sharing

[tinman]

Hi everyone,

here is the Bucking Reluctance Motor I Designed

Link to video: https://www.youtube.com/watch?v=WL3kO4n2XsE

If someone can help confirm if CEMF or Lenz is negated in my test or suggest a test that would be appreciated.

Luc
Something is not right with your CVR,be it the value of .1 ohm,or the ability of it to carry the current.
I am leaning toward the second,as the CVR seems far to small to be able to do the job. If your blue trace is across the CVR,and the VPD on your scope for that channel is 5 volt's,then i estimate the average voltage to be about 7 volts across that CVR during the on time. This is an average current of 70 amps,and the average voltage across the two coils seems to be about 8 volt's,as your VPD are 500mV and your probe is set at 10x<-- not sure why you have done it this way,as that is still 5 volts per division.

So using the screen capture below,i see around 560 watts per pulse,and that CVR looks like a 1 watt CVR ?.

[MileHigh]

Luc
Something is not right with your CVR,be it the value of .1 ohm,or the ability of it to carry the current.
I am leaning toward the second,as the CVR seems far to small to be able to do the job. If your blue trace is across the CVR,and the VPD on your scope for that channel is 5 volt's,then i estimate the average voltage to be about 7 volts across that CVR during the on time. This is an average current of 70 amps,and the average voltage across the two coils seems to be about 8 volt's,as your VPD are 500mV and your probe is set at 10x<-- not sure why you have done it this way,as that is still 5 volts per division.

So using the screen capture below,i see around 560 watts per pulse,and that CVR looks like a 1 watt CVR ?.

I think saw <black,brown,black> on the resistor so that would make it a one-ohm CVR.  So that would translate into an average current of about 7 amps during the pulse which would make it seem reasonable.  The voltage pulse starts at 11 volts, which is the battery voltage.

You should say, "around 560 watts during the pulse" so as to not confuse power with energy.  You quote energy per pulse.

The battery voltage is about 11 volts, and I am going to guess that it is a lead-acid battery that would normally be at 12.6 volts.  So I believe that gives two options, the battery is relatively new but quite discharged, or the battery is quite old.

For the sake of argument let's assume that it is a relatively new battery that is quite discharged.  That means that it's internal impedance is rather high, and that's why you see the huge voltage droop from the battery as it starts to supply current to the two coils.  The battery starts to croak from the current demands being made by the coils.  The moral of the story is to try to do your experiments with fresh batteries, especially if the load will be drawing heavier currents.  Also, when currents are in the range of 5 amps and above I personally would switch from alligator clips to terminal block type connections.

I am not a fan of this "bucking coils" business, for the most part I view it as doing something "alternative" just for the sake of "being alternative."  In this case when the slab of metal is between the bucking coils, the magnetic fields are mostly cancelling each other out.  Even when the coils have air between them, they are cancelling each other out.

If I can make a suggestion to you Luc it's this:  Just wire a switch to turn the coils on and off manually.  Move the slab of metal through the gap between the two coils step-by-step and feel the pull on the slab when you switch the coils on.  Very low tech, just feel what is going on with your hands.  Then reverse the wiring in one of the coils so they are no longer bucking and repeat the same procedure.

I am willing to bet you that you will get a much stronger pull force when the coils are "normally" wired and not in a "bucking" configuration.

Finally, what do you mean by "counter-EMF trying to negate Lenz" for your design?