A bench post about my replication of the high ohm series coil motor that is Lasersaber's EZ Spin.
After watching Lidmotor's marvellous homebuild version. I asked him what he thought of using the 500ohm coils from Dollar Tree solar 'dancing flowers'. Instead of persuing a hope that he might try the idea, I decided to have a go myself.
I've reused such coils in other motors, but only ever 1 at a time.
The Lasersaber method entails connecting multiple coils in series...the end of 1 to the start of the next, all the way around the rotor. More coils are needed than magnets.
It's presumably an old practice, but one which he highlighted with the EZ Spin and was previously unknown to myself.
All of this starts to to gain a 'Muller' feel with the coil amounts and magnet ratios and, indeed my own project may be heading in a similar direction.
This non 3D printed version has 4 coils and 2 magnets...had no more dancer coils than the 4.
Coil ohm'age is approx 1800ohms, 1 coil is of a slightly different design for some reason and 1 had its wire snap the other day during a video'd run.
If you've ever seen these little wonders of a coil design, you'll know the wire is something like 48 AWG !!!
The first version of it used Lidmotor's complimentary pair transistor circuit. Worked great, but unfortunately not as well as a reed switch subsequently proved.
The rotor is 'semi-levitated', in that a needle point sits on the bathroom type tile and its top end sits under a couple of magnets. The same type of arrangement worked great for 2 years daily with a 1 coil motor sat under my desk light to solar power it, so wear on the tile is of no importance.
Here's the YouTube upload that shows the build:
Lidmotor then showed a video, where a 5F supercap had powered his motor for over 10 hours. I decided to try with a 1F supercap, just to see how long the thing would go. Previous personal record was 19 minutes for a 1F cap on any motor.
Result was 11hours !
The only reason it stopped, was because 1 of the thin coil wires had broken, from moving the wiring each time a voltage reading was made with the multimeter.
Here's the 11hr run video:
Where to next ?
Well, since that video the other day, there is a biasing magnet that's being tested for combating reed switch metals pull (i've already snipped the original connections and attached copper wires instead).
A washer has been glued to the middle of the rotor, for stability and low speed running improvements. it will now run down to about 0.165V.
The next build will be an 8 coil setup, then 16. Gen coils and output usefulness tests will include adding a blocking oscillator circuit and/or returning the output to the input via various disconnection methods.
The motor will back charge very very readily. No diode or loop around is needed. Spinning the rotor by hand will charge a cap up, to the tune of 10mV every few seconds on a 0.1F cap. The output with no cap is somewhere around a constant 60mV.
That explains the run times
Connecting one of my multimeters to the motor, with no capacitor fitted and with the rotor moving slowly from a hand spin, I can set the meter to ohms and the rotor will then spin up to a high speed !
Wonder what causes that ?
Also, a stepper motor makes a great 'power source'. Taking any 2 wires from the stepper and adding a diode to one of them, the stepper will charge a 0.1F cap to 0.8V with approx 20 turns of the shaft forward and backward. It can be left 'in circuit'.