Steel-geared hub motor?

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Re: Steel-geared hub motor?

Post by neptronix » Apr 09, 2014 1:47 am

Yea; ATF seems to be the most popular motor fill. Some other lubes can eat at some of the motor internals, i'm not sure which ones, but i would assume that anything petroleum derived would be something to avoid ( those seem to enjoy eating plastic from what i hear )

This motor does have a separate oil section for the gear system, so i'd assume that it is sealed off from the stator. But whether the stator side is very well sealed is up for experimentation.

I think it's kinda cool that they jammed a 7:1 reduction ratio into a geared motor. I'm excited to toy with a Cute Q128H for the sole reason that it has dual reductions inside for a 12:1-13:1 reduction in total. It show's in the motor's weight.. 700-800w continuous in a 6.6lb/3kg package is awesome.
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Re: Steel-geared hub motor?

Post by crossbreak » Apr 09, 2014 5:25 am

neptronix wrote: other lubes can eat at some of the motor internals, i'm not sure which ones, but i would assume that anything petroleum derived would be something to avoid ( those seem to enjoy eating plastic from what i hear )
Ups.. i think i'll go for 0W-30 :? Maybe I should try 5W-40 first, i'm not sure it 0W-30 is "thick" enough to lubricate the gears well enough.

The vendor told me:
Vladimir wrote:It is perfect for 48 V and about 20-25 A.
Do not push it too far and put some fresh oil inside before first use, about one big tea spon.
My plan is 74V 15amps with a sensorless 6-Fet infineon with 4110 Fets (fits under the saddle).. I hope i get no problems with senorless operation at that power... this way i can easily recycle the hall-wires as temp probe wires.

I'll test with a 12 Fet programmed to 15amps @74V and tiny 25A phase current... it seems like the controller catches up sensing at VERY low speeds <1kph, so it should be possible to get a good start up behavior even without halls connected.

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Re: Steel-geared hub motor?

Post by Gab » Apr 09, 2014 6:46 am

Steel gears are very strong compared to the plastic ones, also oil is a good idea for efficiency in the gearbox.

But the helical gears will not be as efficient as the straight spur ones. I don't know what the fascination is with having a totally silent ebike ?

When rideing past someone the tyre road noise will probably be more noticeable so why sacrifice efficiency with helical gears? Also i can't think of anything more dangerous then a high power ebike that is silent and rideing fast next to pedestrians.

That's why people with fast motor bikes one of the first things they do is put a loud exhaust on it, as more ebikes come out quieteness will be even less important. Since when has being silent been a selling point of a fast car or motorbike ?

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Re: Steel-geared hub motor?

Post by Punx0r » Apr 09, 2014 7:06 am

0-30 should be more than thick enough. Have you considered ATF? That's pretty thin and is used in manual and automatic car transmissions at much higher loadings.

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Re: Steel-geared hub motor?

Post by crossbreak » Apr 09, 2014 7:11 am

helical gears will not be as efficient as the straight spur ones
this is wrong. The helical angle is so small (have a look at the pictures above), the influence on efficiency is absolutely negligible. btw helical gears can take more load than straight cut gears of the same size.

Have you ever used a hub motor with straight cut steel gears? Do you know how load they really are? The noise is really annoying, even in rush hour traffic. in the calm grass land it is so annoying i would not want to use my motor at all since it is such an annoying noise :roll:

discussions like this are absolutely pointless...
people who say that something can't work shall not disturb those who do it already
Punx0r wrote:0-30 should be more than thick enough. Have you considered ATF? That's pretty thin and is used in manual and automatic car transmissions at much higher loadings.
as you can read above we already discussed that.. question is, which specific ATF.. anyway thanks for the input, i'll try 0w-30. ATF is really not common here, 99% of the cars here are stick shift.
Last edited by crossbreak on Apr 09, 2014 8:35 am, edited 2 times in total.

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Re: Steel-geared hub motor?

Post by wil » Apr 09, 2014 8:22 am

crossbreak wrote:my plan is 74V 15amps with a sensorless 6-Fet infineon with 4110 Fets (fits under the saddle).. I hope i get no problems with senorless operation at that power... this way i can easily recycle the hall-wires as temp probe wires.
That sounds almost exactly like what I would like to do with my build, I'll be following you and seeing how it goes! (hopefully well)
crossbreak wrote:as you can read above we already discussed that.. question is, which specific ATF.. anyway thanks for the input, i'll try 0w-30. ATF is really not common here, 99% of the cars here are stick shift.
ATF is also used in power steering systems, so see if you can get some power steering fluid (although the oil your using will probably work fine anyway)
Last edited by wil on Apr 09, 2014 8:06 pm, edited 1 time in total.

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Re: Steel-geared hub motor?

Post by Punx0r » Apr 09, 2014 9:10 am

Dextron 2 is the specification of ATF I normally see. There may be other grades but most applications use Dextron 2.

You can buy it in most car accessory or parts shop and in many petrol stations. I have an older car which uses it for its manual gearbox.

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Re: Steel-geared hub motor?

Post by crossbreak » Apr 09, 2014 3:34 pm

that is good news, thx. I'll test tomorrow, my wheel is laced and i'll make a 1:1 comparison with the 500W Bafang CST, same rim, same tires, same controller, same battery... but different motors with almost equal KV (after reduction..at the wheel)

one thing I noticed already after lacing: it freewheels very badly, but turning backwards is very easy, compared with the bafang... it almost turns backwards as easily as it freewheels :roll: maybe a good idea to just block the freewheel... this would allow regen+instant throttle response

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Re: Steel-geared hub motor?

Post by circuit » Apr 09, 2014 4:07 pm

Excellent news so far. :) Waiting for further updates :)
BTW I'm interested how fast can it go... I mean I am interested in 50km/h with 12" wheel, which is around 800rpm. That gives what, 6400rpm on motor? Not too much probably?
Last edited by circuit on Apr 09, 2014 4:15 pm, edited 1 time in total.
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Re: Steel-geared hub motor?

Post by neptronix » Apr 09, 2014 4:13 pm

That's unfortunate about the freewheeling.

That's kind of one of the advantages of a geared motor after all..
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Re: Steel-geared hub motor?

Post by crossbreak » Apr 09, 2014 4:38 pm

circuit wrote:Excellent news so far. :) Waiting for further updates :)
BTW I'm interested how fast can it go... I mean I am interested in 50km/h with 12" wheel, which is around 800rpm. That gives what, 6400rpm on motor? Not too much probably?
around 420rpm loaded @48V, so you'd need 90V xD I'll really measure KV tomorrow when i have my CA alternative connected

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Re: Steel-geared hub motor?

Post by circuit » Apr 10, 2014 12:07 am

You could always use this method (ask google for translation):
http://e-motion.lt/2013/09/02/sudedamo- ... -i-40-kmh/
Call it kv hack or whatever, but that is my intention. :)
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Re: Steel-geared hub motor?

Post by neptronix » Apr 10, 2014 12:15 am

Oh yeah.. delta wye changeover.
I think it's much better just to run high volts.

That's always been the way to hot rod DD motors anyway. Low speed wind, craptons of volts.

My magic pie in a 20" wheel was nuts on 125v, but only hit what.. 45mph or something ... lol.
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Re: Steel-geared hub motor?

Post by Dauntless » Apr 10, 2014 12:48 am

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Re: Steel-geared hub motor?

Post by circuit » Apr 10, 2014 1:31 am

neptronix wrote:Oh yeah.. delta wye changeover.
I think it's much better just to run high volts.

That's always been the way to hot rod DD motors anyway. Low speed wind, craptons of volts.

My magic pie in a 20" wheel was nuts on 125v, but only hit what.. 45mph or something ... lol.
Nope, not delta-wye.. Not all motors operate well under delta. Check the drawing :)
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Re: Steel-geared hub motor?

Post by wil » Apr 10, 2014 8:05 am

crossbreak wrote:no load current @76.5V: 0.91A
That's pretty good, I'm keen to hear how it performs on bike!
Is it only the gear side you've oil filled, or have you done winding side too?

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Re: Steel-geared hub motor?

Post by crossbreak » Apr 10, 2014 8:42 am

there is no "gear side" you could fill with oil. I put in 10ml 0W-30 now... it freewheels A LOT better after I drove a mile. Not really worse than the CST I would say.. but that is hard to "measure". I can spin the wheel to 50kph for example and meausure time till it stops.. I would say it is still a bit worse than the Bafang.

My biggest problem ATM: My sensorless Infineon 12-Fet doesn't like it. It gets issues with phase currents >19A and looses sync :oops: For comparison: with the it looses sync at 65A phase current with the bafang. The steel gear motor has ~1000µH inductance while the Bafang has ~380µH. This may be the cause.

19A phase current isnt a lot of fun.. i can't even get up a 10% grade at walking speeds, i just roll backwards xD Even our 250W Euro street legal controllers use ~35A phase. :roll: :roll:


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Re: Steel-geared hub motor?

Post by Lebowski » Apr 10, 2014 8:45 am

pitty I don't have a second controller lying around (like I put on the recumbent, 100 to 120V, about 30 to 40A rms)

the 1000uH is really crazy, how much erpm does it do for 400rpm wheel speed ?

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Re: Steel-geared hub motor?

Post by wil » Apr 10, 2014 8:56 am

crossbreak wrote:there is no "gear side" you could fill with oil.
I was under the impression that the stator and planetary gear set where isolated from one another, it looks like this would be the case from this picture, and as neptronix said
Image
neptronix wrote:This motor does have a separate oil section for the gear system, so i'd assume that it is sealed off from the stator. But whether the stator side is very well sealed is up for experimentation.
Can you confirm that's not the case, there is no sealing/isolation between sections?

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Re: Steel-geared hub motor?

Post by crossbreak » Apr 10, 2014 11:05 am

sealing?? it's just a bearing... i posted lots of pics ( have a look at the first page). here you can see it:
Image
if oil gets through it, it will get on the windings

@lebowski: it's 7:1 reduction with 8 magnets, it it should be only 187Hz @ 400rpm. I wonder how inductance can be so large :? The slower the wind.. the larger the inductance i thought

could not yet find a hall combo that runs in the right direction and does not pull way too many amps :roll:

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Re: Steel-geared hub motor?

Post by crossbreak » Apr 10, 2014 3:35 pm

this combo works with 120° hall placement.. just swap blue and yellow of both halls and phase wires
Attachments
steel_gear_hub_hall_Kelly_KBS_X.jpg
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Re: Steel-geared hub motor?

Post by wil » Apr 10, 2014 10:26 pm

crossbreak wrote:sealing?? it's just a bearing...
if oil gets through it, it will get on the windings
Thanks that answers what I was asking. I wasn't totally sure how it all went together from just the pictures.
It appears that the only entrances to the winding area is via that single bearing, and a small amount of oil will leak through over time, which will soak the windings and stator, probably just on the bottom.
You might find it better to add oil inside this area next time you have it open before you close it up, it's going to get oil in it anyway, having a larger amount will likely aid cooling, and have more even coil heating, as they all will be oiled, rather then just the bottom ones.

It will likely add a tiny bit of extra drag at freewheel, but like other geared hubs, the extra power potential will be worth it.

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Re: Steel-geared hub motor?

Post by neptronix » Apr 11, 2014 1:40 am

Lebowski wrote:pitty I don't have a second controller lying around (like I put on the recumbent, 100 to 120V, about 30 to 40A rms)

the 1000uH is really crazy, how much erpm does it do for 400rpm wheel speed ?
There are 8 magnetic sections here... even if it's a 7:1 reduction, consider that a 16 pole 5:1 MAC motor will spin up to 560rpm at the wheel, at least, on an EB3 infineon-like controller. That's a pretty insane eRPM..

How do i know? i hit 45mph on a MAC 8T on 72v.

Image

So I don't think that eRPM is a limiting factor here..
My first major build: 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w on a Turner O2 full suspension.
The wheelie machine: 20" Rear Magic Pie II on a Trek 4300 MTB

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