This Post will be updated frequently to summarize progress
This is the official conversion:
If one removes the key that fixes the stator on the axle, the axle can rotate and there is no need for any additional bearings. After you removed the key and screwed the stator to the hub-housing with an alloy-piece, the stator is fixed on the hub-housing, while the axle is free to rotate. The axle will turn in reverse direction after conversion.
Pic that shows the turning directions from page 14
This alloy-piece is called heat-bridge or thermal bridge since it conducts the waste-heat from the stator to the hub, which leads to much increased cooling of the stator. This piece fixes the stator in the hub, prevents it from turning. The screw holes must be machined very concentric, so the stator can not offset from the center. There must be a center alignment, we use the screws for that. Since we ca not use a The pic below shows the stator of a bafang SWXB, which was relatively simple to convert, due it's simple design. This really is a very powerful motor, sadly it's one of the loadest hubmotors on the market, due it's oversized and durable gears. Still I can recommend it for people who want only 1kW. It's still more quiet than the RC middrives I have seen.my first Heatbridge /Thermal Bridge:
The axle still slips on the stator bore, so there shall be some space between these two components. We can make this space by by polishing/filing-down the surface of the shaft, till the axle can rotate without friction. You can also drill the stator bore to a greater diameter, but make sure your heatbridge centers the stator perfectly before you do this.
After a first test assembly to see if it all moves right, the axle has to shimmed right to axially align both rotor and planet carrier. There can be friction and noise which are induced by bad alignment. If you do this conversion, you should buy some shims (12 and 15mm inn dia) for alignment. Sry I've got no pics of the shims.
You may now add an additional Heatsink:
This pic from page 10 show how a heatsink for the stator could look like. thx bob for the pic. there are more if you look at page 10. This way the available continuous output power must be more than 4 of times
the original (ie the MAC can output about 1800Watts, a small 250W bafang can do almost 1000W continuously):
This conversion also enables the option to use both ends of the shaft. This way it can be used as a Jackshaft without using a freewheel crank[/color] Explanation what this does can be found in the wiki: http://endless-sphere.com/w/index.php/E ... figuration
. spinningmagnets writes a step-by-step how-to on page 19: viewtopic.php?f=28&t=45245&start=450#p719603 (work in progress, almost complete)Drive system with dual-freewheel Jackshaft -> much better drive-ability and no more need for crappy freewheel cranks
Wiki article: http://endless-sphere.com/w/index.php/E ... eel_Config
:Speeding up the Motor to get more continuous power
The less magnets a motor has and the thinner the laminations are, the faster we can spin it to gain a good efficiency an thus continous output power. power loss/ heat /inefficiency (=all the same) limits output power in the first place. On the other side, more poles means more torque for a motor of the same size.
Dues these facts, we can compare middrive motors (there is a much better and detailed list by miles i can't find ATM):
The Bafang BPM has less magnet poles (16) and can be speeded up further than the MAC (32poles, it has equal 0.5mm laminations, the BMC and upgrade MAC have 0.3mm). The BMC/upgrade MAC are a good choise for upspeeding, but these are more expensive. The Bafang BPM has a prospective advantage in Power/Weight ratio over the old MAC due this (edit: in fact they are equal), the BPM and the BMC should be about equal (edit: The upgrade MAC/BMC are supperior). Compared to RC motors like the CA120-70 and other low induction motors gain a even higher power/weight ratio - since they are available with 0.2mm thin laminations, just for comparison. BUT low induction motors have special requirements and often fry controllers, if not treated right (which is really hard as I had to experience). Still RC motors can be a good choice for a middrive if driven fast, which means a high reduction ratio.
Gearing a middrive: http://endless-sphere.com/w/index.php/G ... _mid_motorList of people here who try this conversion:
in order of appearancebob
with pics of his mounted heatsink here: viewtopic.php?f=28&t=45245&start=135#p672235mr.electric
pics starting here: viewtopic.php?f=28&t=45245&start=135#p671774studebiker
with some issues and useful explanation about disassembly here viewtopic.php?f=28&t=45245&start=210#p678511whiplash
his new build thread: viewtopic.php?f=28&t=46568&p=681062#p680899spinningmagnets
who shows us how it works using a MAC motor viewtopic.php?f=28&t=45245&start=450#p719603
(work in progress) and viewtopic.php?f=28&t=51603
waynebergmanhttp://www.endless-sphere.com/forums/vi ... 67#p730659Sprocket Adapters
I used 18T 9-speed motor sprocket from an old cassette, it just got worn out very quick. IGH sprockets and chainwheels are much more durable and fit the purpose. Next step is an all left hand drive that uses custom sprocket adapter to make common freewheels and sprockets fit the flatened double-D 12mm shaft of the humbotor. I'll start to sell these at cost soon... should look like this in the end:
Here you can get such an adapter: viewtopic.php?f=31&t=52572
Link to the geared Hubmotors wiki page: http://endless-sphere.com/w/index.php/E ... _HubmotorsSteps you need for converting the SWXB, SWXH, SWXU and Goldenmotor MBG
1. glue the stator to the side cover with epoxy putty, spray a bit of WD40 on the stator carrier, so that the putty does not glue to it, but takes a perfect copy of the shape.
2. dirll holes for 6 holes with a 3.2mm drill. Then M4 cut threads
ONLY IF everything fits fine, proceed:
3. Remove the key, polish/enlarge the stator holder center hole using a filedownload/file.php?id=101495
4. Drill a hole for the cables, pull them through the hole
5. screw the stator holder to the side cover, put in the shaft and rotor, connect a controller+battery+throttle, let it spin....check if anything rubs
[sorry no pic]
6. assemble the hole unit, test again if if anything rubs...let it run for a few minutes and check nothing gets hot due rubbing.
7. Make a mount for your bike, drill holes into the hub housing to fasten it on your mount.