geared motor weird behavior

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Lessss   10 MW

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geared motor weird behavior

Post by Lessss » May 08 2020 3:21pm

OK I've always dealt with direct drive motors. A biker has brought a geared motor to me that is behaving odd.

The motor works, it will pull weight but it operates for between 10 and 30 seconds (longer if not full throttle) then will make an electronic noise (not a physical grinding noise) and stop propulsion but I can immediately let off throttle and back on and get propulsion so it's not an LVC.

I used my tester. The motor and his controller (no-name no sticker but to me looks like a Ku123 but has no red wires for 36/48v select but has white and green) both show as good as does the throttle.

Is this a controller motor mismatch? His original controller died from water exposure and this is a replacement he picked up I think from bms battery(guessing). He threw out the original controller.

Anyone got a recommendation on a cheap controller replacement?
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Re: geared motor weird behavior

Post by amberwolf » May 09 2020 1:14am

Wrong hall/phase combo might do something like that.

Could also be too high an ERPM for the controller.

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Re: geared motor weird behavior

Post by dogman dan » May 09 2020 7:02am

Seems to run, but no power could be that, or just a really poor connection. What happens is its connected, can run at 100w, but give the motor 800w, and two phases run at 800w, and one at 100w. This results in really low power, and it can then start to stutter, but only under load.

I got this effect once when I had rubbed a wire on the tire, but could not see it. two wires intact, but the third phase had two tiny strands left.

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Re: geared motor weird behavior

Post by Lessss » May 10 2020 1:24pm

The two green wires if connected make the motor run constantly without throttle. Are those "learning" mode?
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Re: geared motor weird behavior

Post by amberwolf » May 10 2020 3:49pm

Probably. That usually makes it spin one way the first time you connect them, then the other way the next time, and so on. With a geared hub the casing wont' spin the other way but you'll still hear it run.

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Re: geared motor weird behavior

Post by Lessss » May 13 2020 12:13pm

Nope it didn't "learn" anything. Still operates for a few seconds a noise errr and then no power until release of the throttle reapply. If I leave the greens connected it auto starts and if I touch the throttle it "STOPS" (BWAHAHAahahahahaaaa). It's also slow.

I just don't get it. he swears the same model controller worked previously. Anyone got a really cheap controller suggestion? 36V
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Re: geared motor weird behavior

Post by amberwolf » May 13 2020 2:12pm

It probably did work...with a different phase/hall combination than this one has.

And no, it doesn't matter if you connected all the wires with the same color combination as the previous one, becuase they may be wired to different points inside the controller on this one vs the previous one, making the combination different, too.

What happens with the various different phase/hall combinations?

There should be three that run it forward normally, and three that run it backward (makes noise but doesnt' spin the wheel cuz it's geared with a freewheel inside).

Then the rest of the 36 will have various results from sticking in one spot and grinding to working but being too fast or too slow and making the controller and/or motor hot under load (which may make it shutdown before you can notice the heat if it's smart enough to figure this out on it's own).

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Re: geared motor weird behavior

Post by Lessss » May 13 2020 3:51pm

Yeah I'll have to try other combinations. but now I'll have to find another bike to put it on the try as his 1000W dd motor came in and that's now on his bike. I just with I could find some documentation on these Ku123 controllers that don't have the red select wires.
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Re: geared motor weird behavior

Post by Lessss » May 19 2020 7:03pm

I couldn't get any of the 6 combinations to work. I switched to a SKU95 and that works no issues.
Will have to look at that KU123 on a regular direct drive and see if it is a dud.
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Re: geared motor weird behavior

Post by LeftieBiker » May 19 2020 7:46pm

Looking at that motor I'd be concerned about rust and corrosion in the connections, at the very least.

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Re: geared motor weird behavior

Post by Lessss » May 20 2020 7:36am

No, connectors are all good.
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Re: geared motor weird behavior

Post by Lessss » Jun 27 2020 4:48pm

Got another geared motor it has a damaged hall sensor which is potted, so am running sensorless.
Am using another Ku95 controller as it worked for the last geared motor above.
No Joy.
It works at low throttle but if increased to medium or full it stops spinning under power and makes an Anrhhhhh sound for as long as the throttle is held in. The same sound the motor above was making.

The wires on this were damaged at the axle soI had to open the motor to repair. Once repaired my tester shows one hall is bad.It's potted with a really hard epoxy so I gave up on replacing the hall sensor, no way I'm gonna get through that epoxy without damaging something else. Hall connector is not plugged. Running sensorless. All other connections look good and solid.

It will work hours on end at very low throttle no problem. Attempt to go to med or high throttle even for a second and Anrhhhhh.

If going up a hill it seems to allow just a little more throttle than not on a hill.
Others have had something kinds similar. https://www.pedelecs.co.uk/forum/thread ... wer.15560/

Any ideas?

Anyone with an sku65 want to swap for an sku956
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