Recent content by pf26

@marka-ee : yes - also be considering that very long belts are not available for so specific length you might need... I also tried to use idler roller directly against the little pulley to prevent belt teeth to escape the pulley, but this might put some more wear on the belt for some reasons, I...

The idler roller on the belt increases its curvatures and consequently its losses as far as I understand it.

Yes, that were reasons for me to try the large ring gear instead belts. Along with the easy disengagement of the motor. But still noise problem and probably long term wear due to dirt might make it stay an idea more than my everyday motor. Possibly some will reuse and improve the "ring in a...

Yes, the AT5 belt would required high initial tension so that it does not slip on the small pulley (the large pulley ratio makes the teeth only engage in a quarter of the small pulley - unless I added a belt tensionner - which I did, but at the expense of higher power losses it seems. Belt was...

10mm thick ring was choosen to reduce load on the teeth. The idea was to push approx. 100N of tire force to compensate for most of the bike+me+trailer load weight in a 10% slope. That's about 120N on the ring teeth, and assuming that it is spread on 5-10mm² of tooth area, make up to 24MPa of max...

Forgot to mention that you need to be quite accurate in the rim internal diameter measurement, so that the FR4 ring will fit nicely. Also milling the spoke slots needs calculation, even when the 2 FR4 layers are thin, making 1mm diameter difference, leading to 3.1mm more on the circunference...

The purpose of the intermediate ring is convert high gear module to a lower one, which makes it possible to use a smaller diameter gear on the motor, and in turn to achieve a higher gear ratio (near 20 on a "single" stage). The smallest module 2 gears have 12 teeth only and a somewhat larger...

I use T-Motor P60 170kV. It should provide more than 1kW at higher speeds, but currently very limitted by teeth escaping the ring gear contact - I need to improve this. Probably a higher gear module for the large ring would have helped.

Thks ! The main ring gear was cut in 2 parts of 5mm thick FR4 using 1.5mm diam end mill and then glued one on top of the other to make it 10mm thick. Then I milled 0.5mm thin FR4 sheets (3 parts per ring) with slots to accomodate the spokes positions and glued two layers around the 10mm ring...

For those interested in low weight motors for Ebikes, I've used a drone motor (P60) and a (mostl likely) innovative gear reduction using : - a large ring gear (module2) attached to the rim - an intermediate external/internal freewheeling gear - a spur gear gear module 1 connected to the motor...

@j3tch1u: did you start getting some results on this bluetooth connection ? I'm still looking for an Android based display (mostly to check battery state of charge) and logger for VESC. Can you post what your code if you think it might be reusable, at least the bluetooth part ? Thks.

I think your initial value should be 0 for CRC, not 0xffff.

CRC calculation starts from the data byte (3rd byte of the frame). For instance, only the 04 byte is used in 02 01 -04- 40 84 03 frame. You can use the following site to check, line CRC-CCITT (XModem), input type hex, just enter 04. http://www.lammertbies.nl/comm/info/crc-calculation.html So...

The returned packet (seen from the PC) seems ok (size, start, stop, stable values..) I didn't really check the content. I tried bldc video logger, but it failed to open my Bluetooth serial port (possibly not waiting long enough).

I used https://f-droid.org/wiki/page/ru.sash0k.bluetooth_terminal. Just for testing. The extra 00s probably due to a bug as you mention (no one would know until I scope the data) Probably we can reuse some of the sources ? https://github.com/Sash0k/bluetooth-spp-terminal. Except the comments...