A friend just dropped this off.

hello.
I searched the forum for this, and although it's probably a common question, I wasn't able to find exactly what I need.
I've got a (Liberty I think) somewhat generic Chinese ebike.
I had questions at first concerning my battery setup, but have since created a good 24V power-pack that puts out 25.6V
Although my throttle lights all lit up now, I still didn't feel as if I were getting any kind of assistance to the wheel.
What I would like to do is test the motor directly.
I've removed the wheel from the bike and disconnected the controller and all other wiring.
What I'm left with now is a wheel, with the motor, and a set of wires that come from the motor.
in the set of wires, I have a small wiring connector that holds 5 small thin wires. (red, black, green, blue, and yellow.)
I then have three other wires. All heavier.
One blue, one yellow, and one Green
I tried power Black to blue, and red to green and got a spark! (I fell out of my chair!) lol
So, I don't want to do that again:)
? If I have the wheel supported so it revolves freely. And have the correct wires, If I directly apply power from the battery pack, should the wheel turn?
Thanks for any help in advance.
Sincerely,
policetac
 
You have BLDC (brushless) motor which can't be powered directly from a battery.

Only a brushed motor can be powered directly from battery - bypassing controller.
 
Sorry, No, it doesn't work that way. Unlike motors you are used to, this motor will not do anything except maybe twitch when you hook the battery directly to it.

What you have is called a Brushless DC motor (BLDC). It uses pulsed 3 phase DC to turn. Each of those thick wires represents one set of coils that is fired in turn by the controller. Basically a computer that handles the timing. The 5 thin wires are the hall sensors, they tell the controller where the coils are in relation to the magnets.

Testing it is a bit tricky, But if you have a volt/ohm meter it will help. We will also need to know if you have a geared or gearless motor. If you post a pic of it, we should be able to tell.
 
Okay then...
So, how would I go about checking the motor and or it's component pieces?
As I said, everything "looked" okay once I had a power source going through the system, I had throttle lights that came on and lit more or less as I added or lessened throttle movement. But on the road, I didn't feel any assistance.
 
Phdintheory said:
I tried power Black to blue, and red to green and got a spark! (I fell out of my chair!) lol
Click to expand...

I hope that was not 25V across the green hall sensor or theres a good chance you fried it.
 
http://www.ebikes.ca/learn/troubleshooting.html

There are procedures for qualifying BLDC motor. Your unit appears to be a geared hub motor so it requires turning the wheel backwards by hand when observing switching signal from Hall sensors.
 
The "SPINNING" sound has been identified, the problem has been solved!

The problem is with the clutch.

The cause of the sound is because the external motor housing is turning inside the wheel housing causing the distinctive noise. This is diverting the torque from the axle/wheel to the axle/motor casing. As there must be a mechanism responsible for this fundamental change in the physics, a search for something that had "failed" ensued.


CAUSE: As the clutch was the assumed cause of the problem to begin with, I started there.

Now, as anyone who has followed this post knows..., I've looked at this part quite a few times. (Now add 10 more times:)
But, science told me what it was. It HAD to be there.

Sure enough. Inside the "clutch" mechanism of the clutch itself. (Ie. The mechanism that changes the parameters of the containment)
In this case, an OUTER plastic ring with equidistant triangles (teeth) that interact with an opposing INNER set of these that grip in one direction, while letting the opposite direction slip by.

The "teeth" on these rings were very worn. This effectively let the mechanism (axle) move through the clutch in either direction.
Thus causing the problem.

SOLUTION: Replacement of the CLUTCH or CLUTCH/planetary gear combination.


Thanks to all that helped!

-----------------------------------------------------------------------------------------------------------------------------------------
ORIGINAL POST
Hello, and thank you to all who take the time to read this and offer to help if they can.

I have a generic Chinese eBike that uses a rear hub motor with planetary gears.

This motor recently did not run due to an enormous amount of rust that was keeping it from working correctly.

I took the motor apart, cleaned it exceptionally well, put it back together but now unfortunately have a different problem.
Instead of being "stuck" and unable to move freely, it now seems as if it won't engage correctly in a way that gives it torque.

When I apply throttle, it sounds as if the mechanism is simply turning "inside" the hub instead of engaging the gears and driving the wheel.

(Although when disassembled the gears "are" engaged.)

Please bear with me as I try and explain all this in a way that gets the point across.

The hub motor unit in this bike is able to be removed from the wheel itself as a complete unit. What remains is the wheel, the casing that holds the actual motor, and a ring of gears that the planetary gears interact with to turn the wheel.

If I remove the screws holding the motor cover pieces, the motor (and axle) just slides out. This assembly then looks as if it were a big can of Almond Roca with an axle running through it. One end of the can has a "clutch" ring that rides on top of 3 planetary gears. These gears are supposed to transfer the movement from the axle to the larger gear ring of the wheel. (I'm sure most all of you know exactly what I'm talking about.)

Anyway, all back together the axle turns fairly easily by hand, but occasionally "catches" in such a way that it feels as if it is hitting a "stop" or a place that it feels stuck. It's not stuck though. I've determined that this sticking point is actually resistance from the motor and gears engaging correctly.

The problem is that it doesn't "stay" engaged correctly though. Once I get it all put back together, it feels as if it has "DIS-engaged" from the gears and is spinning freely. If I apply power, it feels and sounds like the whole assembly is just turning inside. Instead of providing power to the wheel it just spins inside the housing.

Does anyone have an idea what it is I'm attempting to describe? If so, is there a fix to this? What's going on? Have I put it back together wrong in some way?

I'm confident that whatever the problem is it should be fairly easy to fix, but for the life of me, I just can't figure it out.

I'd post pics, but I don't have a camera.

Thank you in advance to all that help. I'll stand by for the rest of the evening so I can respond quickly to anyone offering their assistance.

Sincerely,

phdintheory
 
A pretty good description. Sounds like a conventional gear motor construction.

When assembled, there should be no resistance turning the wheel as if the bike is moving forward - here the clutch should be disengaged. You should only feel resistance when turning it backwards. In both cases the resistance or lack of it should be consistent. If you are turning it forward and getting occasional resistance or 'sticking' then there may be rust or junk that worked its way into the clutch. In gear motors like the MAC, BMC, and eZee the clutch is a sprag clutch and both the sprags and an internal bearing are packed with grease and more or less open to the inside of the case - which is normally free of contaminants. Getting junk in there would be difficult but not impossible and could jam the sprags or the bearing. Getting it out would essentially be impossible and a clutch or gear cluster replacement would be in order.

As far as the motor running inside the case without actually doing anything - it sounds like the motor is turning backwards so the clutch is disengaged. This can happen because you interchanged a couple of phase or hall wires. Did you re-wire the motor or could some connections have been interchanged? This is not too hard to straighten out, but it's not something to launch into if an electrical mis-step could not have occurred - (we might look to the clutch again, but the symptom doesn't sound exactly right for that...)

So - questions:
  • In what direction are you turning the wheel when you get the 'sticking' and resistance?
  • Could there have been a wiring error?
  • Are there any markings on the motor to give a better clue as to what it is?
  • Can you take a cellphone shot of the motor case and maybe the 'inner motor' + gear cluster so maybe someone will recognize it...
 
Hello and thank you for your reply.
I'll do my best to answer your questions and perhaps together we cxan come up with a solution that works.

Okay. 1. No, I did not change any of the wiring, nor have any wires come loose, nor are any broken or cut in any way that might cause one or more to short out or cross connect.
2. In what direction am I turning the motor when it sticks? Answer: If the bike is standing up and the wheel is connected, crouching down beside it with the front of the bike facing to my left, the bike would engage the gears (the sticking point) when turning the axle counter clockwise. This would be the same direction as if the wheel was turning with the road.
3. Any markings on the motor? IDK. I would have to take it apart again. (I will do that once I have sent this reply so I can get it oiut to you quickly)
4. I'll try the cell phone pic at the same time.
Again, thank you. I'll stand by
 
To finish your reply,

In your reply you stated that;
..."When assembled, there should be no resistance turning the wheel as if the bike is moving forward."
Answer: There is no resistance turning the wheel in this direction.

..."You should only feel resistance when turning it backwards."
Answer: When turning the wheel "backwards" SOMETIMES there is resistance, other times there is not. (Herein lies my problem) :)

..."In both cases the resistance or lack of it should be consistent."
Answer: It is not consistent.

Your next comments suggest either a possible problem with rust contamination, or a wiring problem related to "phase" or "Hall sensor" wiring.
With regard to these suggestions, I do not believe that contamination is the problem as I removed EVERY piece of rust, every flake of dirt, every boulder from Yellowstone. :)
As to the wiring, I do not believe this is the problem either as I removed no wires, have none that are loose, nor are there any in poor or otherwise faulty condition. In fact, the bike powers up correctly, the throttle works as designed, I have good power response from the battery, and the motor is receiving ample power.

That's all the additional information I have at this time.
Thank you.
 
Rolling the bike backwards is a test of the clutch.
A good clutch will engage when rolling backwards and there will be significant drag while rolling the bike backwards.
A bad clutch will let the bike roll backwards just as easy as rolling forward.
 
"Rolling" the bike in these directions is not possible as I have the wheel off the bicycle for inspection and testing.
It is just too much of a pain in the arse to keep putting it all together, with every screw, mounted onto the bicycle just to see if there has been any change.
I have been able to examine the unit for these changes with the wheel removed from the bicycle and "free" in my hand.
That said, if you notice in the thread, moving the motor assembly in the two different directions results in "inconsistent" mvement.
Sometimes there "IS" significant drag, other times there is not.

However, I do not think your evaluation of a faulty clutch is too far off the mark.

Let me ask you this then. If the clutch were at fault, exactly how does a clutch like this fail? I see no visible breaks or even undue wear on that part, although it does seem as if it "wobbles" a little too much. (as if it were a "bearings" problem. But that may just be my inexperience)

Here's also something I've been wondering.

When I first started to take the motor assembly apart, I pried here and there with screwdrivers, hit it (tapped) occasionally with different tools to "break things free," and finally used the correct "puller" to remove the final "cap."

Is it possible that during one of these "tapping" episodes I might have upset a "clearance" of some kind? (Example: Tapping on the axle might have moved the axle slightly creating too much distance between the clutch and the planetary gears? Thus causing them to not engage correctly?

If so, how close must the clutch ride to the gears? Should there be any play or space between them at all, or does that really matter?
Again, thank you all.
 
what is the previous history of this bike. did it run before in the present configuration? the motor has the original stock controller? same phase and hall sensor color combo?
 
A pic of a roller clutch taken apart.
This one had the small springs become distorted and they stopped pushing on the rollers.

clutch.jpg
 
Phdintheory said:
That said, if you notice in the thread, moving the motor assembly in the two different directions results in "inconsistent" mvement.
Sometimes there "IS" significant drag, other times there is not.
Click to expand...
Right - 'consistent' may have been a poor word - there will be some cogging to the resistence, but that cogging should always be there. It sounds like yours is free sometimes and cogging sometimes. NG.

Phdintheory said:
However, I do not think your evaluation of a faulty clutch is too far off the mark.

...If the clutch were at fault, exactly how does a clutch like this fail? I see no visible breaks or even undue wear on that part, although it does seem as if it "wobbles" a little too much. (as if it were a "bearings" problem. But that may just be my inexperience).
Click to expand...
The clutch carrier actually doesn't turn in normal operation - it just sort of holds the gears in place relative to one another so it's not the precision spinning part you might think. Slop can be 'normal'.

I'm not familiar with your motor and clutch (good pictures BTW :) ) but in general you might expect to find rollers or metal sprags (weird shaped metal thingies) in the clutch. These sort of jam into place or slide freely depending on which way the two clutch sections rotate relative to each other. The clutch can fail by permanently, jamming so it never releases, or by failing to hold because the rollers/sprags can't get enough friction to grab and wedge into place. It sounds like you may have foreign material in the clutch that is preventing the sprags from properly contacting the face on which they normally slide (great picture above!). Just a guess. Again, I'm unfamiliar with your unit but I would be surprised if the clutch can even be opened for service.

I'm winging it here, but it looks to me like you have two options: replace the clutch or weld it up so it's permanently seized. The first requires that you identify the maker and locate a parts source, then remove the old clutch/gear cluster - the second (ideally) requires that you remove the clutch gear/cluster, possibly remove the gears, and get the two rotating sections of the clutch tacked together. I have ridden with seized MAC/BMC clutches for months at a time - it's just sort of a geared DD motor. It's literally a bit of a drag, but otherwise okay. In the big gear motors, the gears are pretty much unaffected (teeth wear on the normally unused face), but the torque arm and key that pins the clutch to the shaft take a bit more of a beating because of unexpected bi-directional torquing. So - your motor 'should' be fine with it - but that's supposition on my part.

So - two things: identify the motor to figure out about parts, and pull the clutch from the shaft - a common task for both approaches above.

  1. Get more help. Go back to you original post, press EDIT and go to the thread title. Change it to something like "HELP ME identify my motor and clutch!". With luck someone will look at your pictures and help out with real expertise and knowledge of this little guy...
  2. Wait a bit to see if you get a ping on the cry for help. If not, You can take a fairly safe path of removing the clutch with a 3-jaw puller. There does not appear to be a circlip holding things together, so mount up the puller and yank the gear cluster. Here's a post with some videos that you may find 'related' but not exactly for your particular motor.

A possible means to salvage the motor if no replacement clutch can be had...
  • At this point there are some things you can try but with a sealed clutch, my experience has been that they generate a lot of hope, some partial but ineffective success, and take a lot of time. My recommendation would be to remove the gears if possible. This frequently can't be done and since your motor was super rusty, I'm thinking you may have poor luck. The little bearing on the gears are important, so we don't want to abuse them with prying, etc. If the gears come off easily (circlip retainer, etc) then Good - otherwise leave them.

    Take the clutch to a TIG welder and have him put two or three tacks to hold the moving sections together on the non-gear side. You're only handling a few hundred Watts so the tacks don't need to be big (lower heat buildup from welding). A TIG guy can be more precise than MIG and get better penetration since you may have to grind the weld flush for clearance - but use whichever kind of welder you can find. I would try an auto machine shop first (yellow pages) and then look at other welding shops, body shops, etc. The machine shop guys will know to cool/protect the thing from heat and can grind the weld flush without contaminating the bearings with metal shards - the other guys not so much. Hard to say but the auto machine shop might hit you up for $30 - $40.
This is a sub-optimal repair, but if you can't locate a replacement clutch and want to salvage some use from the bike for low cost, this should work fine for quite awhile.
 
First of all, thank you for all of the replies, especially the last one. I haven't finished reading it yet, but from what I have so far it appears as if it is going to have some very relevant information.
Why am I posting before I read it then? lol... Because I recently performed another diagnostic test that I can't just let go to waste. So I'm going to post those results then get back to the reply. :)

Okay. So I took it all apart again. Put it all back together again, (This time it "seemed" as if it were catching more reliably)and tested it again. However! Remember I said why put it on the bike when I can test it in my hand? well, after I put it on the bike and tested it (lmao) and got the same results, (just a "spinning" coming from the hub) I decided to remove the wheel from the bike and see what happened with the wheel just sitting there.

When I applied power his time, the axle wanted to move. (Since my wires are part of the axle I couldn't let it though) But.... when I grabbed one end of the axle and hit the throttle, my grip (I was able to hold it) was enough to turn the movement into that spinning sound.

So I'm still at square one unless my answer is in this latest reply.

PS. To the response previous to the last:

The history of the bike is as follows.
I received the bike second hand.
It WAS NOT in working order at the time.
http://endless-sphere.com/forums/viewtopic.php?f=3&t=58473
As the electrical system was going to give me the most challenge, I attacked it first.
http://endless-sphere.com/forums/viewtopic.php?f=2&t=58754
The first thing I did was make a reliable power supply.
(I don't have a pic, but I assure you this is the most stable part of the system!) 24v@10Ah
Then I ran into other problems.
http://endless-sphere.com/forums/viewtopic.php?f=2&t=59990
But I worked all those out and finally started work on the motor.
I got it all apart and ran into the rust I spoke of.
Once I cleaned it well and put it together the first time, I got a motor that WAS trying to work correctly even if it wasn't quite right.
regardless, what it DID do was tell me the status of all the other systems. It told me that they were all in good working order.
(So I'm pretty sure that no other system is going to be responsible for the problems with the motor at this time)
So, that all said, once I have this problem with the motor figured out I should have a reliable well running electric bike.
I'm gonna go find out right now. :)

Thanks again.
 
WOW!
That was an awesome reply!

..." but that cogging should always be there. It sounds like yours is free sometimes and cogging sometimes. NG."
Exactly!

..."Slop can be 'normal."
Okay, good to know. So... there most likely isn't any way to visually detect the condition of one of these parts?
And the thinking is that the diagnostic history, the description of the symptoms, experience, and the lack of alternative causes denote a definitive diagnosis of "the clutch" as the failed part even without visual confirmation. That as such, replacement or creative repair of the mechanism is the suggested course of action regardless of any visual evidence of defect. ....... I can live with that.

..."Change it to something like "HELP ME identify my motor and clutch!".
Okay...... On it. I changed the name of my post and have waited a majority of the day for no reply. Although.....it IS Sunday and there probably aren't that many people out here interacting with these sites. I'll give it a good half the day tomorrow then if needed, put out a more specific thread. Until then, I'll do the research the old fashioned way.... I'll ask Siri! :)

Out of the two options, the first would depend on the ability to identify/locate/purchase the parts. If this is pretty straightforward, no problem. If not, well...... That means my neighbor gets a hold of it. With any luck, it'll end up being the strongest part on the bike! Haha

The 3-jaw puller we got. (Question: Are the gears going to move with the clutch as a single unit? Or do they separate as the clutch moves away?)

So, here we go again. :)
I'll see if I can find some parts, or take it to the neighbor in the morning.

Again,

Thank you! :)
 
UPDATE!!!

The 'spinning" sound has been identified!!!

I don't think the problem is with the clutch.

Apparently the external motor housing is turning inside the wheel housing causing the "spinning" sound and diverting the torque from the axle/wheel to this housing.

So I now need to find out if this housing is supposed to turn at all, and if not determine how and why it is.

Anyone know about this?

Thanks.
 
Another peanut from the peanut gallery but on some gear motors the sun gear can spin on the shaft or the ring gear can spin in the outer housing.
 
Hello,
I just checked the outer ring.....No dice. It's as firmly locked into place as a nerd waiting in the ticket line for next years Comicon convention.

As for the Sun gear, I assume it's the one in the middle that the others rotate around? (I'm sure I've written many papers about this phenomenon:) Anyway.... No dice there either. It's not moving!

Thank you for your suggestions though... Got any more? :)

(edited because I think I might have accidentally offended a previous poster. If so, I apologize.)
 
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