Can you use a geared hub motor as a mid-drive?

[hekdude]

Can you use a geared hub motor as a mid-drive motor if you run it in reverse (reversed the phase wires) to get it not to freewheel? My guess you would have to reverse the sensors as well to get it to run in reverse as well.

 

[Lebowski]

Can you use a geared hub motor as a mid-drive motor if you run it in reverse (reversed the phase wires) to get it not to freewheel? My guess you would have to reverse the sensors as well to get it to run in reverse as well.

Yes, my plan as well for:

http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=37257

It's done already here:

http://endless-sphere.com/forums/viewtopic.php?f=28&t=23259&start=135#p540457

 

[hekdude]

Thanks. simple search gave overwhelming # of unrelated responses.

 

[Rassy]

Why would you want to reverse the direction the motor turns? I would use the internal freewheeling to my advantage when pedaling without the motor running. The only problem I see is when attaching a track cog to the standard threads it will want to unscrew when the motor runs. So the track cog would have to be attached with some sort of locking system, such as a set screw through the collar into the threaded area. Anyway, that's what I plan to do if I ever put another mid-drive together.

Good luck with your project, however you set it up.

 

[spinningmagnets]

An idea I've scibbled on scratch paper on occasion is to take a common 3-speed Internally-Geared-Hub (IGH, Sturmey, Nexus...) and flip it over. It appears as though, if we have the freewheel on the left driving a chainring thats on the rear wheels disk brake flange, it would work.

The 3-speed body could be driven backwards (no reason it shouldn't work?) by a left side chain connecting a track-cog on the left side of the geared hub (hub spinning in the normal direction, cog mounted to the disk-brake flange). Some trike 3-speed IGHs already have a cog attached to the body.

When pedaling, the chain from the rear wheel disk-brake-flange to the 3-speed freewheel would be live, but the stock freewheel on the 3-sp would stop the 3-sp and the hub from spinning when you're pedaling.

I'd gear it so that the 2nd gear of the 3-sp would be used as the starting gear, and 3rd would be used as the top speed gear. First gear would be rarely used, and reserved for unusually steep hills. With the typical 30% gearing in a 3-sp IGH, (second gear being direct-drive), one possible example would be 14-MPH, 21-MPH, and 28-MPH (22, 34, 45 k/h). In normal daily use, it would operate as a 2-speed transmission. On this graphic (thats so totally awesome, it looks like a photograph, thanks MS-Paint!) I'm talking about configuration A.

edit: forgot to mention before...AJ has broken a 3-speed IGH running high-power through a single-stage to the rear axle. If the final-drive chain has a 2:1 ratio (between the axle and IGH), the 3-sp will be spinning at twice the RPMs as the rear axle, and that means the tooth-loading inside the IGH will be cut in half. Plus I wouldn't be running near the power that AJ did.

 

[amberwolf]

Can you use a geared hub motor as a mid-drive motor if you run it in reverse (reversed the phase wires) to get it not to freewheel? My guess you would have to reverse the sensors as well to get it to run in reverse as well.

Assuming it has a freewheel (not all do) then if you run it in reverse, it will *only* freewheel in the drive direction then, and will not drive anything. It would only collect regenerative power from when you drive it from the wheel, and it would do that all the time.

So you want to use it in the normal direction.

There are quite a few middrive motor projects using hubs, and almost all of them can be done using either a geared or a DD hub.

my current in-progress:
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=33246
though it is just ideas for now.