Crystalyte trouble shooting help requested

[docnjoj]

I dont get it? How could the axle strip without ripping out the wires??? Duh! The hub separated from the axle! Wow!
otherDoc

 

[mi7d1]

The threads on the axle were ripped off. The axle has two flat on it to allow it to slot into the dropout. This weakens the threads. Also they are cut and not rolled again weaker. Add me and my ham fisted installation and you see the results. The axle never spun and the other side is holding like it should. That's why no wires were harmed.

I dont get it? How could the axle strip without ripping out the wires??? Duh! The hub separated from the axle! Wow!
otherDoc

 

[mi7d1]

I think it was mostly me that was the cause. I sort of recall a gap being there and I didn't put any washers on. It's like trying to recall a dream. When I put the motor back on it was a day before the race. I probably wasn't pay attention. The wheel was difficult to install due to the axle diameter and the dropout issues most of us face. I had to work the wheel to get it to seat in the dropouts. Knowing me if there was a small gap I would have thought that the dropouts would squeeze together. On the other hand if I'd have seen that large gap I would have realized that my short 4-5" dropouts wouldn't squeeze together that much, the back end is heavily bonded with Carbon Fiber. There would be no flex. I have a feeling that I over torqued the nut to the threshold and perhaps some bumps and or side loading popped the threads. Well, live and learn. I'm off to see if the other motor with the custom shaft will fit. Then I'm going to swap side plates to get the freewheel on. Will see if the gods are smiling on me or not. Thanks all for you help.

 

[fechter]

Bummer

Can you use a longer nut so it grabs on the remaining good part of the threads? A longer nut would be less prone to stripping also. I've heard a lug nut from a Porsche will fit.

Another repair techinique is to weld or braze over the stripped part, then cut new threads with a die.

 

[mi7d1]

Oh No, Mr. Bill is out of the frying pan and into the fire. I was attempting a stator swap. I've removed the stators twice now in the past with no problem. As before I was turning the nut on the gear puller by hand. The stator was coming out, but I couldn't pull it free. Flipped the wheel over to get a better grab and what did I see

Large photo here: http://flickr.com/photos/wmbates/2605502708/sizes/l/

Now what do I do? Are the magnet suppose to be bonded to the hub or held only by their magnetic personalities? The motor is sitting as shown. I might slide the stator back in while I await further directions from the group. HELP!

Could this have been the "growling" I was hearing? The magnets vibrating under a stall condition?

 

[fechter]

That would explain the noise for sure.

Sand, clean with solvent, epoxy. Keep track of north and south magnet pieces. Make sure they go back in the same orientation. They will repel and try to flip over if you get it wrong.

 

[docnjoj]

Prolly better use a hi temp epoxy! Thats incredible! Did the motor overheat?
otherDoc

 

[mi7d1]

I guess this is good news then since the source of the noise has been found. As I understand now since the magnets were vibrating at stall speed this would prohibit the overload from kicking in and shutting down the power to the phase wires.

I'm on vacation again in a week and a half. This will give me time to do some forum searching on loose magnets. If you know of any direct links to the subject I would appreciate it.

That would explain the noise for sure.

Sand, clean with solvent, epoxy. Keep track of north and south magnet pieces. Make sure they go back in the same orientation. They will repel and try to flip over if you get it wrong.

 

[mi7d1]

I'll have to look into and research about the different types of epoxy. I have no doubt the motor has gotten hot. A few days prior to this problem my on/off switch broke while away from home. I took off the tail fairing and the motor was very warm to hot to the touch. I ask a lot from my velomobile that other bikes don't have to endure. Such as running a 20a controller pushing a bike that weighs around 350lbs including the rider/driver. The motor running inside of a tail fairing that has limited air circulation but is a fairly dry environment. Might look into forced air cooling with a muffin fan and some ducting to direct outside air on the motor. I'll also be looking into a higher amp rated controller I hope by next month depending on the stock Justin has. Not sure if I should go with the 35A or 50A. I might even get brave and solder my shunts inside the controller if I have to wait too long. First I'm getting in on the LifeBatt group purchase. I don't want to miss that opportunity. Looking to purchase enough batteries to make two 36v packs more if I can afford it.

Prolly better use a hi temp epoxy! Thats incredible! Did the motor overheat?
otherDoc

 

[knoxie]

Hi

Hmm suspected you may have left a little gap, the arms would have been trying to pull the motor apart, its very important to not do this, for most of us its the other way round and these hubs are a tight squeeze for us mainly, I run washers on the BMX for the same reason and its never a good idea to over torque these motors, the quality of the nuts that they supply should tell you that, deff pop some washers over on the next one.

Looks like the magnets have moved, I have seen a whole rotor full do this!! I have cracked magnets as well, liquid metal will stick them, any high temp industrial epoxy will do the job, you need to get the surface really clean and key one the rotor (hub body) if you can rough it up with some coarse paper, this will help.

I suspect the damage came from the rotor and the stator hitting each other and not the heat, I think it all stems from your installation sadly.

Hope you get it fixed up though.

Knoxie

 

[mi7d1]

Here's a good one for you, I was running a search for +epoxy +magnets and I came across your post. Looked at it for a moment and said to myself that was my thread. I hadn't received notice yet about a thread update.

Hi

<snip>
Looks like the magnets have moved, I have seen a whole rotor full do this!! I have cracked magnets as well, liquid metal will stick them, any high temp industrial epoxy will do the job, you need to get the surface really clean and key one the rotor (hub body) if you can rough it up with some coarse paper, this will help.

What do you mean by "and key one" Are you referring to aligning one up in it's proper position? or do you mean to remove one magnet (keystone) clean and reinstall it then followed up by the other magnets.

I suspect the damage came from the rotor and the stator hitting each other and not the heat, I think it all stems from your installation sadly.

Well I consider myself fortunate that I was able to ride it like that without further damage to the motor or bike. I might have a 100 or so post but I am still very much a newbie :lol: Things were rushed in preparation for the race that shouldn't have been. I had almost backed out a few time due to errors on my part. I payed the piper and now it's time to dance

 

[mi7d1]

Hi

Looks like the magnets have moved, I have seen a whole rotor full do this!!

The whole ring of magnet are loose are not bonded. None are broken. I'm able to slide them up the rotor easily to remove them. I've purchased some epoxy that has a temp rating of -60°F-300°F After removing the stator, I've found small bits of varnish inside of the rotor.

**EDITED** I don't think it's varnish from the windings. There appears to be some dried glue or something in between the magnet edges. Looks like when the magnet ring spun this came loose.

I suspect the damage came from the rotor and the stator hitting each other and not the heat, I think it all stems from your installation sadly.

Hope you get it fixed up though.

Knoxie

Looks like you're correct. One of the magnets has a green paint scuff. There is also a light area of green paint on the stator. I'm getting ready to bond the magnets back in.

 

[mi7d1]

How screwed am I now? There were no broken magnets... till I was picking up a pair to clean and they got away from me, hit each other and now I have two that are broken. Can these just be bonded in their respective place since the magnetic field poles are on the inside and outside radius and not the edge so much. Worse comes to pass and my idea is a no go I do have another hub that I can use. I'd just have to relace it on a 26" rim. It now on a 24" On my way to search for cracked magnets on the forums and see if I can find some answers.

 

[dirty_d]

go for it you don't have much else to lose :lol: what else could possibly go wrong? maybe there are magnets available that are the same size.

 

[mi7d1]

go for it you don't have much else to lose :lol: what else could possibly go wrong? maybe there are magnets available that are the same size.

That's one idea and I had thought of it also. What stopped and cause me to ask first is that as it is now I still have a good hub that could be used if I were to break one on another motor. If I bond the magnets back in with epoxy, it would be very difficult to remove them it it didn't work. Tomorrow I can get another set of spokes and relace the other hub into my 26" wheel. I think that Scoot on This still has some more spoke sets. According to some RC sites a cracked magnet can cause motor power losses.

 

[The7]

Large photo here: http://flickr.com/photos/wmbates/2605502708/sizes/l/

Could this have been the "growling" I was hearing? The magnets vibrating under a stall condition?

[
The whole ring of magnet are loose are not bonded.

At last the cause of "growling" is found. It is caused by the rotation of the whole ring of magnet between the stator and the rotor when the rotor was held by hand. The Hall sensors detected the change of magnet poles. So the STALL PROTECTION was not activated.

It is very similar to my speculation for an PUMA motor when the nylon geares are shed and/or when the outer ring of the planetary gear is loosen and not bonded to the hub. The rotor rotates but not the hub.

 

[mi7d1]

I never put two and two together. Makes sense now about the ring of magnets spinning. Here I was thinking that they were just vibrating and causing the growling. Well I'm dead in the water till I can either work with the two cracked magnets or relace the wheel to the other hub. Thanks for pointing this out bringing it to my attention. Who knows if I ever would have seen the relation between the loose magnet ring and the growling. My minds been so busy lately. I'm 3 miles short of my goal of 500 miles on my bikes in the month of June.

At last the cause of "growling" is found. It is caused by the rotation of the whole ring of magnet between the stator and the rotor when the rotor was held by hand. The Hall sensors detected the change of magnet poles. So the STALL PROTECTION was not activated.

It is very similar to my speculation for an PUMA motor when the nylon geares are shed and/or when the outer ring of the planetary gear is loosen and not bonded to the hub. The rotor rotates but not the hub.

 

[knoxie]

Hi

Hope you can get them glued back in and the other poster is right!! I had a Puma motor that I had assumed had worn gears, it was making the exact same noise as your motor however once up to speed it would work, it just would rumble and go nowhere from a dead start, I tried changing the gears for new nylon gears and I checked the rotor gear wasnt slipping inside the rotor body and everything, the one thing I never thought would be an issue was the magnets!

I have put the motor away for a few months now and fitted an X5, however I am still intrigued to know if this was the problem after all!! if it is then its no fun job stripping down the motor to glue them back in, it is do able though, it would be easier to press the stator out than remove the rotor.

I will do a test and see if I am right, I really wondered why the gears looked ok, never thought it would be the magnets, I have seen this on the Kollmorgen motors though so I should have considered it. Some super strength epoxy and really roughing up the inside of the puma rotor should be enough to keep them in place.

I will report back if it is the case, I suspect that all of the magnets are turning within the rotor body! I can easily check this by popping the wheel apart and marking 1 magnet edge against the motor body, power up the motor and then check for alignment, in the meantime hope you get your ride sorted.

Knoxie

 

[The7]

Wonder if there are any better ways to fix the magnet poles on the rotor other than using glue!?

 

[Jozzer]

We have had some 10 motors with this problem here this month. They all came from a rickshaw taxi company, that use the motors at full bore (4 people on a 70KG rickshaw and a 4011!).
We've epoxied the magnets back, and they seem to be holding up fine now..

Steve

 

[fechter]

Wonder if there are any better ways to fix the magnet poles on the rotor other than using glue!?

Glue is great as long as you use the right glue and the surfaces are clean. The tinyest bit of oil residue will prevent most glues from sticking. Polyurethane glue is more tolerant of oil residue than epoxy.