Muller Dynamo

[Scorch]

Quanta Magnetics suggested I check to make sure the timing magnets are not sitting at an angle.
And, yes, I discovered that some of the magnets were just not sitting square compared to the surface of the disk.
Not sure why as they do appear to be bottomed out in their respective holes.

So I figure; "easy fix", simply uninstall the timing disk and use an arbor press to attempt to square up the magnets" . . .
Of course this was a mistake; never assume that any 'five minute' job will only take five minutes! 

The aluminum hub was seized on the steel shaft because the shaft does not have a flat to accommodate the set screw nor does the hub have any cut out to make way for any burrs that a set screw typically cuts into the shaft.

After completely removing the set screw this timing disk did not want to move at all.
Even with larger tools including vise grips, channel locks, and pry bars; the hub just kept getting tighter and tighter as I tried to remove it due to displaced aluminum between the shaft and hub.   

I finally had to resort to power tools and ended up cutting the hub, and disk, off which, of course, was a pain in the tail. . . 

Time to order parts and clean all the aluminum, burrs, and tool marks off both ends of the shaft. . .   

Oh well.

Hope I don't run into a similar problem when I need to re-configure the rotor for Q3 operation. . . .

I am off the opinion the shaft should have a flat or the aluminum hubs should have a slight cut out where the set screw is.
I used to build medical equipment on an assembly line. The compressor had a cooling fan. One vender provided fans that had this cut out and I never had any problem removing those fans from the compressor shaft. The other vendor fan did not have any such cut out and it was always a pain in the tail to remove those fans. . .

}:>

[Scorch]

Well I did discover there was one, or two, magnets sitting at an angle.
Not sure why, I thought I made sure those were all bottomed in their holes.
Of course that turned into a major pain in the tail just trying to fix that. (see above)

I would still like to use an optical sensor to control the SSR but desire something simpler than an Arduino controller.
Seems to me like it should be pretty straightforward to create a basic circuit that uses a sensor such as this-
http://www.mpja.com/download/18028op.pdf
To simply pulse the relay whenever it sees a gap in the disk.
And should be possible to include a simple pulse width control by way of a pot and capacitor or timer to control 'on time'.

Wish I could find such a circuit - schematic on the net somewhere. . .

BTW: The magnets are set in holes that do not go all the way through the disk therefore not easily removed. . . .

}:>

Hey Scorch

I know 'exactly' what your dealing with. Ive dealt with it also on a mag motor build.

I suppose there are mags made to specific qualities and some not. 

Try this. Remove the problematic magnets and rotate them some and reinstall. What I found is some are not magnetically centered, so rotating them 90% at first will give you a clue it it is an off centered issue or just a field strength issue.  And if it is a field strength issue, too strong, using thin iron wire or thin sheet metal, foil if can be had and apply a bit at a time to the sides of the magnet, around the circumference to shunt the field enough to lessen the field a bit or even to balance out a strong side if off center.

If the few problem mags are showing weaker then maybe get some mags for replacement and see if any 'match' the good ones you have. Or just position them out of their base closer to the sensor, be it reed or hall. And if too strong, push them in a bit, away from the sensor. If possible.

In my opinion, when someone tries to sell a 'good' kit or product, that they would have 'matched sets' when it comes to magnets, just like in a quality audio amplifier, they will use matched sets for output transistors, a some other components.  Thats is the best option and maybe a good recommendation for the company you got the kit from to think about producing matched sets for each kit. I believe Steorn has a magnet mapper for sale. Are they still around? Just a computer tracked rotating device with a hall sensor for mapping the flux densities outside the mag.

Mags

[Scorch]

These magnets where included with the kit.

}:>

Hi Marcx41,

Did you get the magnets from the guy I gave you the info from ? Yes I am unpacking everything and I have everything ready to start working again, Scorch work will help me a lot on somethings I did not know how to put together....

But I got new hopes now that I see Scorch work and that these people are responding to emails and willing to help.

Next month for sure, I will start working on mine again.

TheStone.

[marcx41]

Some pictures for waiting.....

[marcx41]

 Hi Scorch, ( sorry again for my enghish )
if I can help you, I read and see your problem on your post.
An hall sensor control the SSR for the motor without arduino controler on my machine.
It is a TLE 4905 ( Vs max 32v / I output 100 mA ), the SSR take maximum 20 mA and you can connect it directly without pot and additional electronic.... Vs is +24 V, GND is -24v and Q is the + output direct on the SSR ( +3 ) and of course - 24V on ( 4- ).

I think that isn't a bad idea. For the gap, more it is small, less amperes the motor eat, and for the timing it is easy with your original timing disk.

Regard, Marcx41