Has anyone seen Lasersabers new motor runs on 1000uf cap

[conradelektro]

Hi Conrad,

A) Okay, thanks for clarifying this. I knew the diagram was ok, so the word "shorten" (to cut in length) did not cause problem. To put it simply: the reed switch discharges the 1000 uF capacitor via the coils and via the reversed biased diode (discharge current depends mainly on the reverse current characteristic of the diode and the AC impedance of the series coils).

B) I think when you connect the diode in parallel with the coils, this may need a different reed switch position than when the diode is in series with the coils.  The parallel diode keeps up the current in the coils when the reed already is OFF, so the reed needs to be in a position where its own ON time is less than in the case the diode is in series with the coils. IF you readjusted the reed to the parallel diode, then please disregard what I wrote.

C) Thanks for the measurements. You think now the waveform across the switch is not worth checking by the scope (when the diode is in series with the coils)?

Greetings, Gyula

ad A) It looks like the circuit turns into the simple circuit (only a diode) at the time when the Reed switch closes. The short time the Reed switch is closed seems to be enough to charge the cap in the usual way (by rectifying the sinus AC like current with the diode). I no longer see a miracle there. The diode is needed for rectification of the sine wave like AC generated by the coils. The reverse current of the diode seems to be irrelevant for charging the cap, only the forward Voltage is important (and should be as low as possible). The diode SB3100 seems to have a forward voltage of less than 200 mV and the 1N5711 only a little higher (as measured with my multimeter in diode test mode). The diode reverse currents is only important if one wants to run the setup as a pulse motor with such little current.

ad B) I tried to move the Reed switch around, and it is important where it is placed, but no difference in the optimal position could be found (with the diode parallel to the coil). Also with my "ring magnet spinner" I found that placing a diode (or LED) parallel to the coil had a small negative effect (the switch in the ring magnet spinner was a transistor at the same place where I have the Reed switch in my last charging circuit).

ad C) It is till interesting to do scope measurements, but first I want to go to a "double Reed switch". I see no special effect, therefore the incentive for me to investigate the Reed switch charging circuit or any charging circuit is low at the moment.

General remark:

Lasersaber claims to run his little 3D printed motors with less tan 1 µA. My motor needs 500 µA. This big difference can probably NOT be explained by lower friction in his setup and/or higher DC resistance of his coils.

I suspect it has much to do with the Reed switch ON-time which is about 50% in my motor. Therefore I want to go into the double Reed switch next (in order to bring the Reed switch ON time down to a fraction of what it is now).

I wish more people would build such a little motor so that we hear more opinions and get more test results. For me the only miracle left is the extremely low power consumption of Lasersabers 3D printed motors. Some information is missing and it has little to do with charging the cap when blowing air over the rotor. Just my gut feeling after my tests.

Greetings, Conrad

[TinselKoala]

May I make a safety suggestion?

Builders of rotors containing magnets should not rely on glues or adhesives to hold their magnets in place. There should be some mechanical design feature that will absolutely prevent your magnets from being slung off the rotor when it's turning at high speed.

For example, in my Bedini motor I use a plastic jar lid for the rotor and all the magnets are mounted on the rim, but _inside_ the lid. A small bit of glue keeps them from sliding around but they are kept from flying off by the plastic of the lid itself. Other rotors I've made use cavities for the magnets but it is always impossible or at least very difficult for the magnets to fly off due to centrifugal force.

An uncontrolled NdBFe magnet flying across the room can be very dangerous. If it hits something it can shatter and red-hot bits of it will come flying off and may hit you in the eye. Or even worse.

I suspect it has much to do with the Reed switch ON-time which is about 50% in my motor. Therefore I want to go into the double Reed switch next (in order to bring the Reed switch ON time down to a fraction of what it is now).

You really should try a small biasing magnet on the side of the reed away from the rotor magnets. You might be surprised. Put the magnet on a small mount that you can hold steady and move around to find the best spot that will do what you want to the reed's duty cycle.

[wattsup]

@conradelektro

Thanks for the testing and results.

I think that in your build the main limitation will be that they are 6 on 6. 6 magnets need 12 coils like @Lasersaber is using. The way I see it, there is 100% more usable energy in the 12 coils to make the same rotor turn.

The EZ motor should not need a battery or other input source.

But for your 6 on 6 we should not expect any more then what the effects show.

1) I did mention some time ago if you use a diode, then use a 1uf or smaller cap. Right now the diode and cap are more like a load then a pulse source. If you want to see some output, maybe put a diode between the last coil and the reed and the other side of the diode goes into a 100 or so cap and the other side of the cap goes to the first coil.

2) You tried with the reed on the negative side of the coil run. Maybe try it on the positive side as well.

3) Also maybe try the reed between coils 3 and 4. That is the most curious one for me when I get my one EZ motor type. hehehe

4) The other interesting and maybe easier alternative to your wheel is if you can add 6 more magnets, that would be 12M:6C and @Lasersabers is 6M:12C. Maybe that will give you more to work with and the extreme variance will be very interesting to experiment with in comparison to @Lasersabers.

5) The final variance is the magnet to coil surface area that we have to consider if we look at your results and compare it to @Lasersabers results. All of these factors will play an important role and any variance will affect the final results.

Thanks again for sharing.

wattsup

[gyulasun]

Hi Conrad,

Thanks for your answer, I understand and respect your points.

I would make a notice on the double reed switch: maybe you will have a more versatile double switch if you make it yourself from 2 single reeds because a real double reed is more difficult to "adjust" with small magnets than two separate ones (also double reeds are harder to find, though not impossible)

Greetings, Gyula

[conradelektro]

@TinselKoala: I just built a holder for the little biasing magnet and will test it tomorrow. By the way, the six magnets on the rotor have N facing outward (towards the coils), which polarity of the little magnet (on the opposite side Reed switch) should face the Reed switch? I guess it is also N? (I can turn the magnet around easily.)

@wattsup: thank you for the many suggestion, I will do what I can. So many possibilities. Looking forward to your build.

@Gyulasun: I intend to use two independent Reed switches which can be adjusted relative to each other. I did not know that one can buy a double Reed switch. I think that two Reed switches in series do not need biasing magnets, the determining factor for the ON-time will be their relative distance.

I try the biasing magnet (à la TinselKoala) first because it was easier to build (and can be done with one Reed switch only).

Does anyone have an idea why Lasersabers's 3D printed motors need so little current? My hunch is "very short Reed switch ON-time"? The DC resistance of his coils can not be much more than 2K to 3K Ohm in total?

Greetings, Conrad