Self accelerating reed switch magnet spinner.

[TinselKoala]

Yes, very neat indeed!
I have a couple of suggestions. First, I'd use an external transistor or mosfet switched by the internal transistor in the 311. This will allow you to experiment with creating the inductive backspike without fear of blowing the op-amp output transistor.  Next, I'd suggest trying it without the diode, and with a capacitor between collector and emitter of the external transistor. You might find, as I did, that you get even more torque to the rotor at the same input current that way.
A further refinement would be to incorporate an adjustable setpoint for the comparator, by putting a trimpot between the junction of the two 10k resistors, with the wiper going to the op-amp inverting input. Or simply eliminate the resistors and use a trimpot instead.
Keep us posted on your progress and discoveries! (I wish my local guy had better prices. I have to pay him over 2 dollars for one LM311. Ordering over the net is such a hassle, I hate to do it, I like to support my local merchants but that's ridiculous. And Radio Shack stocks the TL082 in the stores... for 2.49 each!!!)
What happens if you use a lower value for the damping or bypass capacitor? I found 100 pF was all I needed there.

[MileHigh]

Conrad:

Good on you for your build!  That's a very cool chip, a comparator and a transistor all wrapped in one.  If you can mount the rotor vertically somehow then you can move the sensor coil around to change the start pulse angle.  Also congrats on using the relay coil for your sensor coil, with so many turns it must be quite sensitive.

MileHigh

[conradelektro]

Yes, very neat indeed!
I have a couple of suggestions. First, I'd use an external transistor or mosfet switched by the internal transistor in the 311. This will allow you to experiment with creating the inductive backspike without fear of blowing the op-amp output transistor.  Next, I'd suggest trying it without the diode, and with a capacitor between collector and emitter of the external transistor. You might find, as I did, that you get even more torque to the rotor at the same input current that way.
A further refinement would be to incorporate an adjustable setpoint for the comparator, by putting a trimpot between the junction of the two 10k resistors, with the wiper going to the op-amp inverting input. Or simply eliminate the resistors and use a trimpot instead.
Keep us posted on your progress and discoveries! (I wish my local guy had better prices. I have to pay him over 2 dollars for one LM311. Ordering over the net is such a hassle, I hate to do it, I like to support my local merchants but that's ridiculous. And Radio Shack stocks the TL082 in the stores... for 2.49 each!!!)
What happens if you use a lower value for the damping or bypass capacitor? I found 100 pF was all I needed there.

I followed your experiments with the TL082 and will incorporate your suggestions in my experiments next week. The set point of the comparator definitely has to be adjustable, as in your TL082 circuit.

I had problems with oscillations and many particularities of OpAmps are still a riddle for me. An interesting new field for me.

I have long given up buying components in a shop. It is sad that the local electronics distributers die out, but there are even more worrying developments, like the decline of local food production. We will soon all eat the same gene manipulated and poisoned food out of gigantic factories.

Conrad:

Good on you for your build!  That's a very cool chip, a comparator and a transistor all wrapped in one.  If you can mount the rotor vertically somehow then you can move the sensor coil around to change the start pulse angle.  Also congrats on using the relay coil for your sensor coil, with so many turns it must be quite sensitive.

MileHigh

I experimented by moving the trigger coil to different positions by hand. In my crude set up every position from 120° to 180° in respect to the drive coil was good. The duty cycle is always near 50%, very much independent from the trigger coil position. A ring magnet spinner seems to act differently to a rotor with individual magnets on its circumference.

I like to build smaller motors which need very little power, and there the relay coils help a lot. It would be impossible for me to wind such small and delicate coils myself. The hair thin wire is difficult to handle. But the trigger coil can always be very small and delcate, even in bigger motors. My little core less trigger coil produces a sine wave at a few Millivolt at 50 mm distance from the spinning ring magnet, therefore hardly any drag on the spinner.

I have a little motor with magnet bearings in the works. The smaller the motor the better the bearings have to be. A needle bearing , and a stabilization magnet at the top end of the axle=needle, as in LaserSaber's 3D printed motors, is a very good solution for a small vertical motor.

May be a smaller motor with comparatively strong magnets would show anomalies better than a bigger contraption?

Greetings, Conrad

[TinselKoala]

Just a short little demo, showing the MHOP powering a 5-neon ring oscillator, and including the full set of current schematics at the end.

http://www.youtube.com/watch?v=uGja8eggDmM

I forgot to include the input power meters; this is happening at 24.8 volts at about 150 mA input. The driver and strobe circuit uses about 20-25 mA of that (at 12 volts).

[synchro1]

@Conradelectro,

Quote from you:

"We will soon all eat the same gene manipulated and poisoned food out of gigantic factories".

Consider moving to Costa Rica; Pura vida!