Lumen I already know all the results you mention. You seemed to have missed what I asked you.

I told you to spin both magnets and conductor together and use an electrostatic compass near the rim of the disk. This will show you whether the rim is more negatively charged or positively charged due to electrostatic induction. You can probably use a different method to show it as well. But if this is the case then this proves the EMF on the plate caused the charge gradient right?

Doing the experiment that I suggested with the different size disks and same size magnet, would also prove the EMF on the plate caused the charge gradient and not the external circuit.

GB your experiment makes sense if you already accept that the EMF is caused on the disk. But I'm sure lumen has a reason why this is not the case, even though it's as clear as black and white.

I tried to measure something with my prototype by holding it and spinning myself with a voltmeter in my hand - imagine how that looked like: Dancing with magnets

Anyway, my voltmeter can measure as low as 1 mV, but I did not see anything on the voltmeter. Now I have very few turns, only 10 or so, but very strong magnets. I tried to flip the magnet from side to side like wipers on a car, but faster, and could not measure anything in both AC or DC on the voltmeter. However, if I moved the coil back and forth over the same magnets, I measured up to 5mV.

This means the wire has to cross the magnetic lines in order to get a measureable result. I cannot confirm if there is voltage indicated below 1mV in @brolis setup or not, as my voltmeter cannot measure anything below 1mV.

Vidar

Stick it on a rotor and crank the rpm up and then see what you get. If you still get nothing then we have a problem.

This is an example of some Homopolar generator designs showing the suspected outputs and some known outputs. If the last example did produce current it would be over unity so therefore it could be concluded that a magnetic field does rotate with the magnet even when rotated about it's axis.

I should have noted that the output on ALL these setups are out the axial connections and not at any other point.
Also, you need to look closely at what is moving in each configuration.


#1 setup cannot produce output because both legs of the loop cut the field in the same direction and the output is canceled.

#2 Has output because the loop is stationary and the field magnets are rotating in opposite directions. This configuration still suffers from Lenz's law and as the load increases so will the energy to rotate it.

#3 Will produce no output for the same reason as #1 above it.

#4 If this configuration actually did work then the search for an over unity generator would be over. However because the FIELD ROTATES WITH THE MAGNET there will be no output because the lines of force are never cut by the disk or the external circuit.

This is the setup that I have not tested! It also will prove that the field actually does rotate with the magnet. (If there is no output)

@All, this thread of Brolis is a good read.

Somewhat related: I spun a 2inch diameter 0.25inch thick neo disk mag, poles on the faces, at about 4000RPM.

I measured about 150mV open circuit between axle and rim, and 300mA closed circuit. I did not have proper brushes, just my meter probes pushed against the moving surfaces so very noisy, with proper brushes the values would probably be much higher.

I presume most of the electons flow through the thin nickel magnet coating which has much lower resistance than the neodymium bulk.

Like many of you I would like to remove static brushes and have the takeoff and load rotate in the same frame as the disk. If the takeoff and load is rotating with the mag and it still produces this current then something weird is going on that the books don´t mention.

With such a low voltage, the only thought I have at the moment is to charge a small electrolytic cap rotating on the magnet. charged via a diode so as not to discharge when stopped. Spin it all up, then stop it and quickly measure the cap. Whether I can find a diode that would pass such a small voltage I don´t know yet? If I can´t then I will use a very high resistance instead, spin it up for along time then stop and read the cap very quickly before it discharges.

The capacitor and takeoff leads will need to be seperated from the magnet using a moderate shielding material like multiple tin and card laminations, otherwise the takeoff leads will produce a current (via the same effect) that fights against the disk current.

Hi Yucca
Would your demo have been subject to Lenz's law?
peter

hi Peter,

I´m not sure myself, I´ve heard many say that homopolar generators with static brushes will suffer from lenz. But I fail to see how when I imagine the field which will behave for all intents and purposes just the same as if the magnet were still.

The only mechanism which I can see slowing the mag disk (in the static brushes config) is conservation of momentum, as the electrons are thrown off the disk they would tend to slow the disk, like an ice skater spins faster with their arms pulled toward the body and then slows when the arms are extended.

To draw any conclusion I will have to test myself by measuring the disk RPM very accurately with the brushes in contact but the takeoff circuit open, then close a switch to short out the takeoff circuit and see if the RPM drops.

To do this I will need to create some mechanicaly stable brushes, at the moment I push probes against the magnet and the speed is all over the place as my hand pressure varies slightly. Any ideas on easy brushes with fairly low friction are appreciated.