Manual balancing made a huge improvement. After getting the right mass of epoxy putty at the right spot on the outside of the can, most of the vibration is gone. The phone app I was using to measure vibration reported almost a 10x decrease in the amplitude of the vibration.
Is this a reference to Revolt motors ? I was reading through that thread. Early on I thought the motor can't be that bad, surely it is just the hall sensors. But it seems several people with different setups and controllers simply can not get it to run efficiently?
Yes the unbalanced bell is really annoying.. Kudus that you could fix it by yourselfdistrict9prawn wrote: ↑Oct 10 2018 8:48amI had similar problems to madin. My motor was not factory balanced and had a ton of vibration. I managed to balance the motor with by adding trial weights to the outside of the can. I don't know if the stock bearings were bad or if the vibration damaged them, but they quickly developed some play, even before I had actually ridden the bike. I replaced them with sealed ones.
Yeah i have seen this. awesome work!I'm using the AS5147 rotary encoder as this is supported by the vesc.
Good to know you can do wheelies at 350A That makes me believe there is some room above on my conservative 250A setting.I had chain drops on my first few rides. The usual alignment and tension problems. After sorting those out I was able to crank the phase amps up to 350. Crazy stuff. Despite being geared so high and with the 4s battery pack in the front box I can still wheelie.
Do you mean your bearings were very loose in the stator? Able to remove with fingers? My bearings were a press fit into the stator. I did notice that one seat was a fair bit tighter than the other, with both the stock bearing and my replacements. I just used a cheap sealed bearing from https://www.thebigbearingstore.com/r10- ... -5-8-bore/
I think most foc controllers out there will be interpolating between the mapped hall values to get a bit more accuracy. And once the motor is spinning nicely they should really be using foc to get the rotor position. I have the sensorless transition set to 1500 erpm which is something like 3 - 4 kph. And I could probably use much less with no issue. So no I don't think it makes a huge difference, unless trying to crawl up a really steep hill or using PID position control. My main reason for using the encoder was the simple mounting. I saw your hall sensor mounts with the tiny magnets. Nice work The main problem with the encoder setup is that the high speed SPI connection needs twisted pair over the clock and signal line with cables over 10cm. Otherwise the controller gets overwhelmed with bit errors and it just doesn't work.There was also another guy posting pictures in my thread about using an encoder instead of hall's.
Do you think there is an advantage over hall sensors (together with FOC control)?
If one is using trapezoidal 6-step commutation, it is a fact that hall sensors offer accurate enough position, but with FOC where the magnetic field can be applied in any direction, it could make a lot of sense to have finer position resolution.
I've got the 100kv. The controller is vesc6 based, with shunts on each phase, not just two.btw: with your actual 12/91 redcution yours would be geared even quicker than mine (when including wheel size into the calculation)
On my motor the bearings were secured with some kind of thread locking glue, but after cleaning off the rests both bearings just fell into the stator. There was virtually no radial play, but definitely no press fit.district9prawn wrote: ↑Oct 14 2018 2:31amDo you mean your bearings were very loose in the stator? Able to remove with fingers? My bearings were a press fit into the stator. I did notice that one seat was a fair bit tighter than the other, with both the stock bearing and my replacements. I just used a cheap sealed bearing from
That doesn't sound good if it's barely a slip fit.
Yes I have regen set on a second throttle. I have it set quite high (no rear disc brake) at 1.5kw and 150a phase to get as much low speed braking torque as possible. At very low speeds I set up the controller to short the windings in order to get smooth and powerful braking almost down to zero speed. I played around a little bit with active braking but it doesn't seem necessary unless you are trying to lock the rotor in a certain position.
Those QS midmotors usually come with a belt drive, but they don't have internal gear reduction.Tommm wrote: ↑Oct 25 2018 9:23amI'm thinking of something similar with the (I think inrunner) QS motor 2000w mid drive it has 120 stator diameter and 70 magnet height. It looks very high quality. Some guys use the 3000w motor in dirt bike conversions, it can take 15kw easy (11kg), so the 2000w(~7kg) should be good for 8kw minimum. They have 4.7:1 internal gear reduction.
The one I linked has 4.7:1 reduction, and low (3500 max) rpm, it is enough to have 1.5x reduction by chain or belt after it. I have the same with a cyclone, 4500 max rpm, and 6:1 internal. If you put 1.5x on the rear you can go 60kph on 72v before field weakening. So the reduction is easily enough.madin88 wrote: ↑Oct 26 2018 5:05amThose QS midmotors usually come with a belt drive, but they don't have internal gear reduction.Tommm wrote: ↑Oct 25 2018 9:23amI'm thinking of something similar with the (I think inrunner) QS motor 2000w mid drive it has 120 stator diameter and 70 magnet height. It looks very high quality. Some guys use the 3000w motor in dirt bike conversions, it can take 15kw easy (11kg), so the 2000w(~7kg) should be good for 8kw minimum. They have 4.7:1 internal gear reduction.
Regarding the stator diameter they refer to the outer diameter and not the airgap (as usually).
I think the air gap dia of the 2000W motor will be more like 70mm..
I'd agree that the heatsink on the fets should be plenty given how much copper is attached to the pcb. This controller was meant for fighting robots so they would have zero airflow unless they use fans. I'm going to order pcbs for the new version. The active components are all the same as well as the DC link ceramics. Screw terminals for phase and battery is a nice improvement and tvs diodes for over current and over voltage faults should shut everything down much faster. It looks like they ended up going with the same 80v common mode current sensors though. If they used isolated current sense then it would be a legit 20s controller since gate drive and fets are 100v rated. That would make it competitive with something like the asi bac4000. Which I've also been drooling over.madin88 wrote: ↑Oct 29 2018 9:01amToo bad the controller got damaged and you could not fix it.
I wonder if that large heatsink on the backside which looks like it covered bus bars and many other parts would have been even necessaray.. Normally it should be enough if you just cool the FET's.
Are you going the build same controller again? In the forum you shared the link i have seen there is an improved version of this VESC available now