Cytronex motor...resistance when turned backwards ..there is none

[NeilP]

I have just been asked to have a look at a Cytronex kit fitted to a Canondale.

Basics...it is dead..does not provide assist.

Not seen one of these before

I am assuming a geared motor ? so if i were to spin it backwards i was expecting it to provide resistance, turn the motor backwards, and get pulses from the motor plug. with an 'e-bike tester' connected to it.

But nothing ..no resistance, no voltage output from the motor.

Two handle bar switches..lights and assist on/off. Lights work and assistance light on the handle bar switch both activate

Do not have a sensor-less controller to test the motor with, and since this bike has no throttle, can't really figure a way to activate the controller to test its output.

Should this geared type motor provide resistance and spin the motor when wheel is spun backwards? I know other geared types do this, but this motor I have not seen before.

Wondering about stripped gears in the motor?

But not going to strip the motor or remove and open up the controller yet till you guys can hopefully give me some more info

Thanks

 

[jerrysimon]

I use Tongxin motors (used on the Cytronex conversions/kits) and no restistance as it uses smooth roller bearings not nylon gears. Usually a little bit of resistance when you turn them backwards though.

The system is complicated (I just use a bog standard controller and thumb throttle) though I think its changed over the years. I had one of the early ones with a button at each end of the handle bar.

The roller gears are retained inside a steel ring. As such its very hard to strip them down. If you seach the forum I have posted detailed pics in a post or see below.


https://www.flickr.com/photos/45051578@N05/albums/72157623881672012

 

[NeilP]

OK, thanks jerry

I I have stripped Tarn motors that also use a smooth roller system. But they do give full resistance when turned backwards..you can feel the motor itself being rotated when the wheel is rotated backwards.

I have just put the wheel back on the bike and with the bike in the stand, but motor not connected I can measure voltage at the controller output pins when spinning the front wheel whilst also turning the pedals.

i am going to try rigging the controller to a bog standard hub motor and see if it spins that

Since the Cyronex motor is of the type you picture it sort of kills my theory of stripped gears..so we are back to an electrical problem.. damn#

 

[flecc]

Since the Cyronex motor is of the type you picture it sort of kills my theory of stripped gears..so we are back to an electrical problem.. damn#

Unless it has a cracked ring around the rollers, something they can suffer and that could mean no drive either way. I've no personal knowledge of these, but I know Jerry is aware of the various mechanical failures possible in its drive system.
.

 

[NeilP]

 

[Deleted member 4366]

The motor should generate A/C between any pair of phase wires when you spin it backwards. If it doesn't, then you need to look inside it for the cause of the problem.

 

[NeilP]

Yes, that was what I was expecting too, but it turns just as easily backwards as forwards..as I said in the first post, there is no resistance to turning it backwards..the motor is not being turned when the wheel turns backwards.


Judging by the sound it makes..the motor is knackered..so stripping it tomorrow

 

[jerrysimon]

Sounds like the ring is cracked to me and the rollers are just spinning without any traction on the ring. That would explain why it is so easy to spin either way and if the motor is not turning why their is no voltage generated. You could open it up (you will need to make a tool to get the side plate off) to confirm.

Quite frankly if that is the case its not really worth fixing as its difficult and by the time you get parts shipped it would be cheaper to get a replacement motor and rebuild the wheel. Easy enough to order now from China.

 

[NeilP]

OK, so what motor do I order. ?
I can order a ready built wheel from the supplier

at £250

But ordering a motor alone? what do I order..is it going to end up any cheaper?

Think it is probably easier and quicker just to order just the complete wheel.

 

[Deleted member 4366]

If it's the narrow motor, the Q85 from BMSBattery is pretty good. If the forks are the standard 100mm, then the 260 rpm Q100H.

 

[jerrysimon]

If you want the same motor they will cost between £100-£130 direct from China, dependant on postage and duty tax.

The exisiting motor should have markings on it but my guess would be 36v, 175RPM or maybe190RPM if you want a faster wheel. Again not sure if you need a 36 or 32 hole motor dependant on the existing rim.

Send an email to sales@h9.com.cn telling them what you want. This is probably the motor

http://www.h9.com.cn/product/?id=336

Thats the V brake one, they also do one with a disc brake fitting. Here is the link for all the motors in that range

http://www.h9.com.cn/category/186/

Or as you say the easier route would be to buy a replacement wheel from Cyctronex but of course nearly twice the price.

http://no-hills.com/electric_bike_shop/product.asp?strParents=0&CAT_ID=24&P_ID=159

 

[NeilP]

Thanks for the links

useful for later if not now

Yes the 175RPM motor.

I am just going to get the owner to order direct from Cytronex. Less work and hassle for me..and it is totally his fault it has failed...I found the issue on stripping the motor.

It is his fault because he did not listen to me last year. I saw the bike outside the local farm shop, and put a note on it telling him it needed some work doing to it.
He never got back to me..but a few months later, while talking to a friend of my father, it turned out to be his bike.

I asked him if had done the work I suggested..he said 'No, it will be OK'

The work was a very simple job...turn the front wheel the other around so the wiring had a drip loop and the wire entered from the bottom.

Yep, it had filled up with water over the last year or so and the grease and rust has turned in to a lovely grinding paste. Also the little springs that push the balls out for the clutch had rusted away to nothing.

So ..new wheel and motor from the UK and we can have it back and running in a few days as opposed to weeks to wait from China, then re-lacing the wheel

 

[Deleted member 4366]

I know it's not your bike, but those motors are troublesome. The alternatives are much more reliable.

 

[NeilP]

I think for his use the original will be just fine, totally standard usage, up and down a hill a few times a week.

For me the alternatives will be more troublesome, as they will give me more work. Original will just be a matter of swapping wheel and plugging it in..

 

[jerrysimon]

I have found the Tongxin motors ok providing you treat them with some care i.e. no powering up before starting to pedal or expecting it to pull you up hills with no effort on your part.

I would admit they they seem to me more reliable in small wheels, at least that has been my experience.

In terms of the exisiting electrics you are probably right, a like for like replacement as a simple swap out is probably the easiest route to get him back on the road.

 

[NeilP]

I have 'fixed' the old motor for now...replaced the springs on the clutch mech with springs from ball point pens.

Still sounds bloody awful , and it is knackered..but it does now work.

He is hopefully going to order a new one !

 

[Nealh]

I have 'fixed' the old motor for now...replaced the springs on the clutch mech with springs from ball point pens.

Still sounds bloody awful , and it is knackered..but it does now work.

He is hopefully going to order a new one !

Imaginative, good temporary job for now then.

 

[NeilP]

The pen springs were a tad too big in diameter,
Cut them down to half length and they did the job.

Getting the 3 rollers and the ring back over the drive pin was a major fiddle though.


Sent from my iPhone using Tapatalk