8Fun Planetary Gear Motor Use, Improvements, Troubleshooting

Electric Motors and Controllers
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usertogo
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8Fun Planetary Gear Motor Use, Improvements, Troubleshooting

Post by usertogo » Nov 27, 2017 10:53 am

I have purchased quite a few of these very inexpensive planetary gear driven hub motors that are marketed here as 250W Trio brand, but show inside the 8Fun cast mark. After I once shortened out the windings after a hill that was driven for too long with 1500W (via 72V System instead of 36V). Now I have limited it on the latest motors to just under a 1000W and added a fine creeping oil as heat exchange fluid. It helps because I can smell the oil if the motor gets hot. The motor doesn't have a build in thermo sensor...
Now after many km (400?) I finally ran into a problem and the motor seemed to slip and have limited traction. I thought now is the time to get the metal gears the plastic probably melts when I drive near a 1000 W for a while... I was surprised when I opened the motors and the gears look like new!
IMG_20171125_172704Trio-web.jpg
Trio 8FUN Gears
(166.19 KiB) Not downloaded yet
IMG_20171125_172621Trio-web.jpg
Trio 8FUN Gears
I will probably still get a set of metal gears (mine have 36 teeth) for preparedness and if I go on a long distance journey with this setup!
But what could be slipping so noticeable yet relatively quiet? There is a key that is fine, and I can't imagine the main outer gear could slip pressed into the housing as it is?
The only one left I think is the smaller motor gear or the mechanism in the planet center that also does the reverse freewheeling?
Any hints highly appreciated!

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amberwolf
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Re: 8Fun Planetary Gear Motor Use, Improvements, Troubleshooting

Post by amberwolf » Nov 27, 2017 10:32 pm

if it's like most it has a one-way clutch, this can slip either because of the oil (probalby not) or because of wear or becuse the clutch cracks like this:
viewtopic.php?f=2&t=15570&p=576368&hili ... mp#p550415
Image


someitmes you can fix them like this
viewtopic.php?f=2&t=86124&p=1260122&hil ... h#p1260122

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motomech
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Re: 8Fun Planetary Gear Motor Use, Improvements, Troubleshooting

Post by motomech » Nov 28, 2017 8:40 pm

Yes, the Sprag clutch is probably slipping.
Sometimes the little springs that keep tension on the rollers get weak or break. One member here actually found replacement on the Net as a hardware item(not an ebike motor part)
Metal gears-They were all the rage a number of years ago, but nobody could stand the "dentist drill" sound 3 pr.s of metal gears produced. Using one pr. became the common practice for those that thought they needed them.
Why do you think you need them?
Since the original gears are fine, it's hard to see the logic of replacing them.
"If it ain't broke...."
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, 2.4 Holly Rollers run ghetto tubeless. 25 mph. Mean Well HLG-320H-48A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 12S LiPoly elifebike 9-FET 17A controller. 20 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

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usertogo
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Re: 8Fun Planetary Gear Motor Use, Improvements, Troubleshooting

Post by usertogo » Nov 29, 2017 5:45 pm

motomech wrote:
Nov 28, 2017 8:40 pm
Yes, the Sprag clutch is probably slipping.
Sometimes the little springs that keep tension on the rollers get weak or break. One member here actually found replacement on the Net as a hardware item(not an ebike motor part)
Metal gears-They were all the rage a number of years ago, but nobody could stand the "dentist drill" sound 3 pr.s of metal gears produced. Using one pr. became the common practice for those that thought they needed them.
Why do you think you need them?
Since the original gears are fine, it's hard to see the logic of replacing them.
"If it ain't broke...."
Thanks for the info. Do you think driving at a multiple of its rated power does cause that problem? I was considering using the motor for the next years Sun Trip 2018 race, which goes for 12000km! Taking a spare etc...
IMG_20170927_182130viaKAwebES.jpg
Fat Bike Prototype
Now however I got a new front motor which is direct drive and can do regenerative braking ( https://www.aliexpress.com/item/60V-96v ... 88673.html ) and will probably keep that rear motor just as possible backup if the primary front motor fails...

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motomech
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Re: 8Fun Planetary Gear Motor Use, Improvements, Troubleshooting

Post by motomech » Nov 29, 2017 7:12 pm

Without taking it apart, it's hard to say what is causing the slipping.
BMS Battery actually sells the entire gear set/clutch for a couple of Bafang mini models for $19.
Of course the shipping will be a killer if that is all that is ordered.
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, 2.4 Holly Rollers run ghetto tubeless. 25 mph. Mean Well HLG-320H-48A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 12S LiPoly elifebike 9-FET 17A controller. 20 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

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