self destructing bike

[gillettadam]

Been using the electric bike for some time, it's been brilliant. However I was going down a relatively steep hill and had a fair bit of speed on when all of a sudden the rear axle locked up and span which of course completely ******ed the motor cable. Does anyone know why it would jam like this, once I'd stopped it was completely free so it wasn't a mechanical fault. Also is it worth repairing and if so does anyone have any 8 core hall cable about?

 

[banbury frank]

Hi Where are you in the UK

Can you turn the shaft in the motor

can you post photos

Frank

 

[JuicyBike]

For some motors, designed for re-generation, or controllers with the same intention, a great deal of current can be created whilst free-wheeling down hill. This can cause the motor to get very hot and could be a possible cause...

 

[gillettadam]

The wheel turns fine, and it's all as it should be, or looks it anyway. I'm in Wootton near Oxford. There isn't anything to take pictures of, it all looks fine except for the mangled wire, but I will split the hub open and take a look and take some pictures of the internals

 

[flecc]

If it's an SB type internally geared motor, you might find the nylon gears partially chewed up. They can suddenly lock the wheel.

 

[gillettadam]

It's not a geared one, no gears in the motor or on the chain!

 

[flecc]

In that case I can only think of two possibilities with a direct drive motor. One, a bearing breaking up and momentarily locking (unlikely), the other Hall sensor cable lost connections turning the motor into an instant electric brake.

 

[PJM]

Was the shaft still tight in the drop outs or had it come loose and rather than the motor locking it had just spun loose with the wires causing the lock up?

 

[banbury frank]

Hi gillettadam
We can rewire the motor We are in Banbury Just down the road

But beware It may have damaged the Hall sensors in the motor and the controller



Frank

 

[gillettadam]

it was tight in the drop outs, after loosening the axle nuts I had to really heave with a 10 mm spanner to twist the axle back to where it should have been. How much would I be looking at for a re wire of the motor?

 

[banbury frank]

Hi If you can open the motor just pull the cable trough and cut off the damaged part and re solder using Color To Color Then sleeve with Heat shrink

The reason it spun in the rear drop outs is no drop out adapters



To open the motor and sort the cable £80

Frank

 

[gillettadam]

I think I'll do it myself then! There is a large amount of wire damaged so if anyone has any 8 core hall 7mm outer diameter about it would be very appreciated

 

[shemozzle999]

Still available in the classified section PM me if interested:

http://www.pedelecs.co.uk/forum/classifieds/10407-replacement-motor-cables.html

 

[gillettadam]

I've sent you a PM, thanks

 

[Scimitar]

In that case I can only think of two possibilities with a direct drive motor. One, a bearing breaking up and momentarily locking (unlikely), the other Hall sensor cable lost connections turning the motor into an instant electric brake.

Ah yes; that partially happened to me when I had mine out for a dry run - I'd installed the motor, but not the batteries and had cable-tied the wiring up on the rear rack. As I pedalled around a corner, there was an almighty racket from the back and it felt as if someone was holding me back - I think the output wires had touched (bullet connectors). I know it wasn't the Hall wiring, as they were in an encapsulated connector. It only lasted a second and then a bump in the road put paid to it.
I'd imagine if I'd been going faster downhill and the short of the output had happened over a longer timespan it might have been destructive.

 

[gillettadam]

well chaps I've got the motor out. There are 3 hall sensors, and one looks to have definately fried. the other 2 I'm not sure about. The numbers are from right to left s41 301 unreadable s41 303 the middle sensor being the unreadable one. Is it possible to just buy generic hall sensors from ebay to replace these, as these are quite cheap whereas I can't find ones with the same number

 

[banbury frank]

Hi gillettadam

we keep them in stock £3 each if you come to Banbury I will show you how to remove the old ones

Frank

 

[gillettadam]

I've read an instructable on replacing hall sensors and the chap used ss41s it is possible that the first s is covered in resinand I can't se it on mine, is it worth getting some ss41 sensors?

 

[flecc]

The ss41 series are Honeywell Hall sensors, here's a data sheet for them. I assume the middle one of the set is ss41 302, but the only reference to 302 I've found on these is the usage and storage upper temperature limit on this sheet:

Data sheet

And here's one for sale at Farnell:

Honeywell ss41 Hall effect sensor (1154 in UK at £1.16 each)
.

 

[gillettadam]

I put the new sensors in, and wired up a new cable, and went to try it out when there was an almighty fizzle and then everything died. I discovered that a fuse in the battery had blown. so I replaced the fuse and it happened again. I assume this means a blown controller? If much more like this happens I think I'll cry!