Friction drive Tidalforce project (Ghetto electric v4.0)

[def215]

i havent realized that your mount for the drive looked like that todd.

38mph on a friction drive is impressive to me. what size spindle are you running? if i recall was it around a 1 inch spindle? i like it! it seems very stealth with it set up that way, but the rc motor whine probably give it away as being powered.

 

[EVTodd]

i havent realized that your mount for the drive looked like that todd.

38mph on a friction drive is impressive to me. what size spindle are you running? if i recall was it around a 1 inch spindle? i like it! it seems very stealth with it set up that way, but the rc motor whine probably give it away as being powered.

I've had around 4 different versions of the mount itself. The last one actually clamped on to the frame but wouldn't fit on this bike without changing it quite a bit. The sliding part that holds the motor has been the same since I switched to rc stuff. I keep saying I'm going to fancy it up a bit but once I get one put together I start riding it and it never happens. I did base/clear the cover on this one at least. lol

The roller is 1.25". 38 mph was fun and I'm positive you could pretty much go as fast as you want with friction drive but I'm just not comfortable at those speeds on a normal bike. It did climb the hills around here like a champ though.

Stealth was the original goal of this whole thing. You can't even see the one on my bike (panniers cover it completely). But yeah, the rc noise gives it away if I'm pushing it. Not bad at partial throttle though.

 

[adrian_sm]

That is the thing I have noticed the most since I have been running my friction drives with a power limit, they are so much quieter.

- Adrian

 

[add-e]

Well this is quit a old post so maybe you had the chance to improve the drive and reduce the noise.
I tested a lot and finally also used RC stuff for my drives but there are many possibilities I´m sure you did not test out.
Nowadays RC-Controller can have more than 24 kHz for switching the phases.
They higher the switching frequency the more agreeable the sound is.
I´m sorry I did a but documentation but I do have a video somewhere I tested my own controller algorithm where I changed the PWM frequency during half speed and constant load.
I started from 4 kHz and ended up with 40 kHz and I can tell you the noise is completely different.
I hope to have some time in the future to work again on the controller.
Now I do use RC stuff 24kHz and big cooling area for the ESC. 24kHz is not the best for high turn outrunners but when freewheeling is possible the losses are Ok for what I would say is good motor sound.
(Sorry for my bad Englisch)

 

[EVTodd]

Well this is quit a old post so maybe you had the chance to improve the drive and reduce the noise.
I tested a lot and finally also used RC stuff for my drives but there are many possibilities I´m sure you did not test out.
Nowadays RC-Controller can have more than 24 kHz for switching the phases.
They higher the switching frequency the more agreeable the sound is.
I´m sorry I did a but documentation but I do have a video somewhere I tested my own controller algorithm where I changed the PWM frequency during half speed and constant load.
I started from 4 kHz and ended up with 40 kHz and I can tell you the noise is completely different.
I hope to have some time in the future to work again on the controller.
Now I do use RC stuff 24kHz and big cooling area for the ESC. 24kHz is not the best for high turn outrunners but when freewheeling is possible the losses are Ok for what I would say is good motor sound.
(Sorry for my bad Englisch)

I never really did anything to try to reduce the sound. I actually like it . Keep in mind too that I'm running at 36 volts with high rpms because of the roller I'm using. More rpms translate to more noise. I've never found it annoying at all though, just not as stealthy as a hub motor. If you run it below it's max it's fairly quiet.

 

[recumpence]

I actually prefer some sound. I enjoy hearing the motors and the various mechanical bits doing their thing.

Matt