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Ruddy's Mini Mill
ruddycrazy:
G'day Guy's,
After seeing a few guys on the forum making mini mills today for a bit of fun I started making mine today. I had a play in autocad to see if 200mm disks would be the right size and doing a count on the 16x13mm round N50 neo's I have left over from my 4kw motor conversion I have enough to do a 16/12 configuration
The drum brake assembly I got for the 4kw conversion had the hub left over and a quick look found the bolt pcd is 100mm which will work purfect with the 200mm disks. I cut both disks out of some 4mm plate and in the morning I'll start counter boring the seats for the mag's. I did find with the countersunk holes on the 4kw kept the mag's seated nicely and with 21 of those N50's sitting all with the same pole up never moved once seated. As I'll be using 2 neo's per magnet pole the counter bores will hold each mag in place on the installation. As there is only 22.5 degrees between each north and south pole I'll use some stupid glue to hold each pole in place.
Now I have seen other guys mag rotors where the corrosion starts on the base of the magnet where it touches the backing plate so for a novel idea I'm going to stamp out some of the motor rewind insulation and put one under each mag so the mag base will be insulated from direct contact with the steel but not interfere with the flux path.
As this will be my first dual axial flux genny by going the 16/12 array I reckon I should get away with less turns per coil as there are 4 instead of 3 in each pole. In the autocad pic the coils are 30mm wide and as shown I could go a bit bigger.
For the blades I'm going to make my first real job on my cnc I'm thinking of making a set of 600mm blades so the blades would be 1.2 metres diameter, but until I do the one coil test I won't know if 1.2 metre blades will too small as I reckon this little baby will be pushing out a bit more than 200 watts.
Thats it for now and tomorrow I'll throw some pic's up of the work I have done so far.
Cheers Bryan
bj:
It's always nice to see leftovers put to work Bryan. Sounds like you buy like I do, when the prices are right,
buy lots, as you never know. Should be a sweet one.
ruddycrazy:
G'day Guy's,
Bit of an update but no more pic's yet. Both magnet rotors have been countersunk and the front magnet disk has all the Neo's on, held in place by stupid glue. Went and priced up some fiberglass resin today and $25 for a litre is way out there so time to hunt around for some at a cheaper price. For the blade mount I found and old shaft stub so this week after work I'm machining it down and I'll use the same taper lock system I have on my 1.5kw motor conversion this will bolted on the front disk. Now I find using the 4mm plate there is no magnetism on the rear side so that is a good sign.
I did ask the Q in the IRC about using polyester fiberglass resin for the stator and read on the otherpower site Dan used to use it so for this small stator I reckon it should be OK. There are 4 tapped holes right behind the hub on the old rear brake mount so they will be purfect for bolt the stator mount. With the magnet rotors I put a 19mm SS band around but with the magnets only 13mm high and the plate 4mm thick that left 2mm protruding on rear of the disks. So I'll use some caulk around it to ensure it is totally sealed so no moisyure can get in.
Hopefully by this weekend I'll be doing the one wire test and as there are 4 coils in series it will be a guess at what turns to use to suit a 24 volt system. If I can get the space I'll use 14awg wire and get the ohm's right down so this mini can make some real power.
Cheers Bryan
artv:
Hi Bryan,...like bj said nice to see using whats available..
"Both magnet rotors have been countersunk".....curious as what that means exactly??
looking forward to your progress.........artv
dave ames:
Sounds like shes gonna be a beaut there Bryan! We will be following along with the progress.
The idea of the insulating between the magnets and steel rotors has to be a step in the right direction..should be invisible to the magnetic flux i should think and stop any electrical circulation to help ward off the galvanic reaction that may be the cause of the corrosion we have seen start under the magnet poles.
Good stuff! That's a lot of magnet there for a mini..we predict a very low turn count and super low resistance :o
it's all good fun!
cheers, dave
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