Shimano DH-3D37QR failed after 370m

[fixedgeartony]

New Shimano DH-3D37QR 6v 3.0w Centre Lock Disc Dynamo hooked up to Lumotec IQ Cyo. Working flawlessly for the last 370 miles and commute to work this morning, now fails to give any more than a faint glimmer, tried two separate Lumotec IQ Cyo lights to rule out the light.

anyone else had similar issue..?

[Brucey]

that model generator has a true ground connection. So may the light.  If the wires are connected the wrong way round the light may work until the hub locknuts or the lamp bracket breaches the paint, and then faint glimmering may ensue.

You can test the generator by shorting out the connections and  seeing how that affects the rundown spin of the wheel. With the short in place, it should be as if the brakes are dragging, very different from there being no connection to the generator.

cheers

[fixedgeartony]

Brucey, thanks for the advice. Tried shorting, no discernible difference. Also reversed cable wiring. Finally removed wheel attached light and still nothing. Borrowing a multimeter tomorrow to test hub.

Cheers.

[Brucey]

sounds a bit worrying...

IIRC this model of hub generator has aluminium windings; so do many others mind (which are not known for being unreliable), but I have always thought that aluminium ones might more easily go open circuit.

I have a couple of these generators which are so far OK, and a friend of mind has had one for several years and it has been OK too.

cheers

[mzjo]

I have never liked the idea of aluminium windings in a situation where condensation could cause problems; I am sure copper would be much more robust and reliable. But, AIUI, Shimano use aluminium in pretty much all of their current production - cost and weight advantages against long term reliability, I suppose.