big black and flyin mags

[hiker]

rebuilt big black--8 and 6 ... 53 winds per coil #14plastic coated insulated wire[its what i had].

turned out a little heavy -and sence my little 7.5 alt takes care of my needs for the motorhome--i decided to try out big black on a exersize bike..

worked out great --with the low windings i didnt have to fight the resitance in the wire..disconnected the batt. from the motorhome and hooked up big black to the batt cables then turned on all the lights-plus i hooked up a extra 100 watt auto headlight.

no problem on doing that--close to 300 watts..real easy with just a 100watt headlight.

well i decided to go all out and hook up a 38volt aircraft landing light--it has two elements on it-400 watt and 1000 watt..hooked up the alt to the 400 watt element..

well --i was doing great getting close to 31 volts--pumping like crazy--

BOOMMMM.....mags go flying past my face at a terrific speed..seemed as if time froze for a long while--i could hear those mags flying every where..looked down and saw i lost the mags on one rotor..second rotor was still loaded with all mags..takes awhile for the alt to lose speed --doing all i can to stay away from that secound rotor..

--dang one close call--had a mag gaurd on it earlier[moped rear fender] but took it off to make ajustments--and of course forgot to remount it..

well what happened was -the finale pully[made from plywood] that mounts to the alt was a little off center and caused some vibration--it was okay at lower speeds but amplfied at the higher rpm--anyway the mags broke loose-stator was not damaged in any way..

i will rebuild it one more time and make a better set up-mount the bearings on each side with the stator and rotors in the middle...

just happened to look at the part number on my bearings[hmmm]

every thing i used those bearings on met with some sort of baddddd.....

still lookin for mags-lost four sets --found a few on the house roof -backyard-frontyard--be safe out their......later.

[electrondady1]

yikes! i got the same bearings, you made made me go check the casting numbers i'm ok.

[zubbly]

hi Hiker!

if just one of those flying mags hit you in just the right place, you might have become, well........a unik   lol!

be carefull!

zubbly

[Titantornado]

Any idea at what RPM things went wrong?

[richhagen]

Thats pretty neat, except for the flying magnets of course.  I built one with an off the shelf DC motor, but there was a little vibration in the mount that would cause the chain to jump off every once in a while.  I've yet to get around to fixing that.  It's been sitting in a basement unused for a year or more now.  Rich

[hiker]

must admit thats about the most dumb'est thing ive done yet..

could have very well been the last......

[reinoud]

Am i right to note that you are indeed using poly-urithane (PU)? (spelling?) for the stator?

Nice bearing blocks btw, i've got a couple of them here too :-D nice idea to put the two bearings like this on oposit sides; maybe it could fix a little bearing slack i found in a similar one.

The thing i'm curious about is the mounting of the rotor blades to the axle, have you machined a hub for it? or what have you used for it? I'd love to see an image of it for i'm struggling to find a good solution for it myself. My temporary solution is to use another bearing there, but that might not be the best way to do it

cheers,

Reinoud

[hiker]

it was geared up  to about 10 to 1..

one turn of the crank = 10 on alt..

i had it going at some outragest rpm....

it was a great set up[was made as a windgen]--next time i will spread the bearings across from each other..

shorted out to a auto amp meter it would put out 33 amps at 1.7 volts.thats with me pedaling like a mad dog in heat...........

with a 50 watt load you didn"t even no it was there--100 watts you could feel it some what-like riding a bike on a flat road--at 300 watts  you could feel the load--but still manage to pedal for awhile[all depends on what shape your in]..

  i have another bike with a motor conversion mounted on it...works okay for 110 volt use..maxs out about 300watts --but its a lot harder to get that--have to fight all the resistance in the wire..will post some picts of that if anyone is interested..

[hiker]

thats a plywood stator -with cutouts for the coils--then the coils are pressed in..

had some old boat resin laying around so i used that to secure the coils-

every thing was compressed between two plywood disks-untill the resin setup..

my hub is  made from layers of plywood -with angled cutouts for the blades..

it all slides over the 3/4" shaft and bolted down..

[reinoud]

thanks a lot for your info. I've got another question though how do you connect your rotor discs (with the magnets) to the axle? Do you use a layered aproach there too and glue or bolt them too?

Nice idea about the stator; i was playing with the idea too though i'll have to abort my plans for that in my current project since the coils are too close to eachother. A variation with a plywood disc and a plywood rind would work though! Attaching the coils with some fiberglass matts and resin to the plywood... now that would save heaps of resin/epoxy! thanks for the idea

cheers,

Reinoud

[hiker]

those are 12" saw blades--i put a 7.5 saw blade on front and back side of each blade to help make it more ridged--mags are glued on plus nylon strapping tape wrapped around the outer side..rotors are bolted on to the 3/4" shaft -nuts are super glued also..

real hassle to take apart--i belive the super glue works better than locktite..

i would like to screw those mags on--wonder if they make a drill bit  for ceramic materail?

or i could make some cutouts[for the mags] in a piece of plywood and then screw that down to the rotors...later............

[hiker]

32 mags per rotor[lowes ceramics]

made into 8 block mags double stacked per rotor.

may have over loaded the blade[one blade is not as thick as the other]

think i will use a single layer of mags on that blade from now on..

just some more info.............