Author Topic: Dyno light problems  (Read 4915 times)

Dyno light problems
« on: 27 June, 2018, 08:53:20 pm »
I have a luxos IQ2 purchased from Phil OTP. I've also got a Shimano Dyno hub from Karla temporary not much OTP. Problem is I can't get them to work.

Got the little Shimano connector thing tonight and put the wires into that and pushed on. Now my first question, is there a positive and negative coming off the hub or is it ac? This then goes through to the light which has +in -in and the same out but believe that's for the rear light to run off.

Any suggestions or how to test. I don't have another lamp or hub to try on. I did have to open the lamp as the out terminal had got flattened in transit

If I had connected wires wrong way round would it have blown anything?

Thanks

Kim

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Re: Dyno light problems
« Reply #1 on: 27 June, 2018, 09:21:17 pm »
It's AC, but with some devices optionally earthing one terminal to the frame (a hang-over from the days when wire was expensive enough to make it worth only running a single core cable).

A potential gotcha is when the dynamo connects one terminal to the frame (as most Shimano ones do), and a light connects the other, so current flows through that path and shorts out the dynamo (which won't cause damage, but will prevent the system from working).  Convention is that anything with an electrical earth symbol, and (on B&M lights) minus symbols and black wires with white stripes should be connected together.

But I don't think that's your problem, since there's no rear light - I'd expect the Luxos's mounting bracket to be electrically isolated, so the polarity wouldn't matter.

Have you actually ridden the bike, or just spun the wheel?  The light may need to charge its battery/supercapacitor (not clear if this is a Luxos U or B) for some tens of seconds before it starts to work.  Spinning the wheel by hand is surprisingly feeble in comparison to riding at even modest speed.


FWIW, the Luxos manual is here:  http://en.bumm.de/fileadmin/user_upload/179/179_LUXOS_B_U_Anleitung.pdf


And in case you've cocked it up, wiring a Shimano lego brick connector works like this:



Separate the two parts of the connector, insert the stripped and twisted wires into the grey part, and fold back into the groove, then click the grey part into the black part to secure the wires.  It then push fits onto the hub terminals.


If you have a multi-meter, the dynamo should measure a couple of ohms on the resistance range when not turning, and you should be able to measure some tens of volts on the AC voltage range when you spin it.

Re: Dyno light problems
« Reply #2 on: 27 June, 2018, 09:27:37 pm »
There is a rear light but it's not connected. I need to fix the terminals for this. I've only spun the wheel so may connect it and go for a ride and see what happens.

Kim

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Re: Dyno light problems
« Reply #3 on: 27 June, 2018, 09:28:49 pm »
Right.  Get the front light working first, before connecting the rear.  Much easier to troubleshoot that way.

Phil W

Re: Dyno light problems
« Reply #4 on: 27 June, 2018, 11:30:25 pm »
It is the right hand set of Luxos connectors you need the wires connected to.  Which way round did not matter on the SON it was running off. Make sure it is not shorting out the way you have it wired up.

Re: Dyno light problems
« Reply #5 on: 28 June, 2018, 10:17:16 am »
Thanks Phil it is that side I've connected to. I'll have more of a play over weekend.

Re: Dyno light problems
« Reply #6 on: 28 June, 2018, 06:33:58 pm »
So found a battery and got the multimeter working. It appears there is no voltage coming out. I'm trying to take the reading off the two kinda terminals on the hub.

Any suggestions? Does the hub a draw to trigger it?

Thanks all.

Re: Dyno light problems
« Reply #7 on: 28 June, 2018, 06:40:51 pm »
the hub is as simple as can be; there is just a length of wire inside wrapped to make the stator winding. It should read a few ohms resistance when measured with a multimeter, and if you simply short circuit the generator connections the hub will become noticeably more difficult to turn.


If there is no output there has to be either

a) a break in the circuit or
b) a dead short on the output

cheers

Kim

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Re: Dyno light problems
« Reply #8 on: 28 June, 2018, 06:46:26 pm »
Double check that you've got the meter on the AC volts range.  You won't measure much of anything on DC volts.

Re: Dyno light problems
« Reply #9 on: 28 June, 2018, 07:09:07 pm »
Def on AC. Tried wire across and couldn't feel more resistance.

Re: Dyno light problems
« Reply #10 on: 28 June, 2018, 10:51:32 pm »
Quote
and if you simply short circuit the generator connections the hub will become noticeably more difficult to turn.
In principle and this may appear counter intuitive, but shorting does not load the generator. It's current limited, so no volts and 0.5 Amps equals no Watts. Lights actually have thyristors built in to short part of the AC cycle and pre regulate the high voltage you get from these generators. It  is reported there actually is less drag under these conditions. Will test this tommorow and report back.


Re: Dyno light problems
« Reply #11 on: 28 June, 2018, 10:57:41 pm »
Quote
and if you simply short circuit the generator connections the hub will become noticeably more difficult to turn.
Sorry, counter intuitive, but shorting does not load the generator. It's current limited, so no volts and 0.5 Amps equals no Watts. Lights actually have thyristors built in to short part of the AC cycle and pre regulate the high voltage you get from these generators. There is actually less drag under these conditions.

nope. 

The current drives against both reactive and resistive loads, and there is mucho drag esp at low speeds.

If you had tried it you would know this; turning the axle in a loose wheel is rather difficult and if you spin the wheel in stand it is like an electronic brake.

The effect of brief bursts of thyristor activity whilst the bike is at speed is very different to this.

cheers


Re: Dyno light problems
« Reply #12 on: 28 June, 2018, 11:02:23 pm »
I stand corrected, and just  had second thoughts. I should have experimented  before posting.

Re: Dyno light problems
« Reply #13 on: 02 July, 2018, 07:09:10 pm »
Tis the hub. OD lent me a wheel. Fitted, connected and the lights lit. Gonna take the wheel apart and have a go at seeing if anything can be done as kinda at the nothing to lose stage

Phil W

Re: Dyno light problems
« Reply #14 on: 02 July, 2018, 07:44:09 pm »
Good to hear the lights I sold you have not broken in transit.

Re: Dyno light problems
« Reply #15 on: 02 July, 2018, 08:29:01 pm »
Thanks Phil. Karla said the hub was fine last time he tested it so looks like I've just got unlucky. Hopefully I can fix it....just need to find my headset spanner I've not used in about 20 years to undo the hub

Re: Dyno light problems
« Reply #16 on: 02 July, 2018, 10:03:53 pm »
before you take the hub apart, have you tested the windings for continuity?


Re the headset spanner; if the hub innards are less than averagely tight then you might get them out with a headset spanner. If the innards are averagely tight or worse, all you will do is wreck the octagon on the hub. The correct tool for the job is a full octagon spanner. Shimano sell one. 

IME hub inners vary from needing about 30ftlbs up to well over 150ftlbs to come free.

cheers

Re: Dyno light problems
« Reply #17 on: 03 July, 2018, 07:10:27 pm »
I've tested resistance which is zero. Thanks for the advice about the tightness I can probably borrow a socket to fit

Re: Dyno light problems
« Reply #18 on: 03 July, 2018, 08:25:53 pm »
zero?  It ought to be

a) infinite - if there is a break in the circuit or
b)  a few ohms (not many, could measure 'zero' on some multimeter settings) if the windings are good or
c) genuine zero (if there is a dead short)

be very sure that you know which it is before you start taking things apart. I would counsel getting a second opinion (from someone who is skilled in these things) if you have any doubts whatsoever.

  BTW removing the internal isn't difficult to with the right tools but it does not give you good access to the wiring unless you also dismantle the RH bearing etc.

cheers


Oscar's dad

  • aka Septimus Fitzwilliam Beauregard Partridge
Re: Dyno light problems
« Reply #19 on: 04 July, 2018, 12:38:00 am »
Tis the hub. OD lent me a wheel. Fitted, connected and the lights lit. Gonna take the wheel apart and have a go at seeing if anything can be done as kinda at the nothing to lose stage

 :thumbsup:

Re: Dyno light problems
« Reply #20 on: 04 July, 2018, 12:21:33 pm »
Engineer at work confirmed it's showing infinite resistance. He also cracked the hub open which thankfully was light pressure on a spanner. Will see what we can see. Have spoken to a company that repair electric motors etc to see if they will have a look

Re: Dyno light problems
« Reply #21 on: 04 July, 2018, 12:55:24 pm »
time take the RHS of the hub internal apart then. Chances are that the break in the wire (s) is in the exposed section of wiring at the RHS.

Note that there are two or three distinct arrangements depending on how the hub is built, specifically

a) if the winding is copper or aluminium and
b) if the hub has a ground return connection or not.

If the hub has a ground return connection you will find that the stainless steel connection plate is in contact with the axle, comes away after you have undone the RH locknut and of course there will be no sign of a wire connected to it. 

I don't know how the winding is physically configured if it is aluminium; I assume that there must be mechanical connections somewhere since soldering aluminium wires is not at all easy, and these might be vulnerable to failure.

In copper winding hubs with a ground return connection the ground connection is made beneath the winding somewhere and there is a single wire running out along the axle groove.

In hubs that do not have an earth return there are two wires in the axle groove. In any case the wires are set in the groove with some soft mastic; the insulation isn't particularly impressive here and you only get so many goes at flexing the wire(s) at this point before they are liable to fail or generate a ground short e.g. because the cone threads chafe through the insulation as the cone is removed.

In most hubs if the winding is basically intact the wiring can be extended by joining lengths of copper wire (that then sit in the axle groove) and the joints can be kept well enough out of the way of the hub shell; typically there is 2-3mm clearance from the RHS of the hub (the part that unscrews) to the stator.

If the whole winding is to be replaced this ought to be possible (there is just one coil with a claw-pole configuration) but the difficulty is likely to be separating the laminations to allow a new coil to be installed. Any deformation of the laminations will cause the magnetic properties to deteriorate, and it usually appears to be semi-potted with some varnish. There is usually a nut that mounts the coil assy to the axle; I'd assume this needs to come off as a starting point. A competent rewinders may have a good repair scheme. You can of course simply replace the centre part of the hub, but it usually costs almost as much as a whole new hub. Then again a repair/rewind won't necessarily be cheap either.

Please post photos if you can, I'm sure they will be of interest to others.

cheers

Dave_C

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Re: Dyno light problems
« Reply #22 on: 04 July, 2018, 01:51:07 pm »
@DaveCrampton < wot a twit.
http://veloviewer.com/athlete/421683/

rogerzilla

  • When n+1 gets out of hand
Re: Dyno light problems
« Reply #23 on: 04 July, 2018, 03:02:15 pm »
My B&M Avy light was labelled the wrong way round compared to the Shimano hub.  Only works with + to - and - to +.
Hard work sometimes pays off in the end, but laziness ALWAYS pays off NOW.

Re: Dyno light problems
« Reply #24 on: 04 July, 2018, 06:48:09 pm »
Got it out of the hub body tonight. It's twin wire. Nothing obviously broken and no resistance picked up on most of it. The wires go into the centre and are then covered by kinda tape so can't see much. The outer part. Not the magnet as this is attached to inside of hub body but the bits that look like bars going from alternating sides are interesting in that one gives a reading of resistance across it. I may go for broke and try and split it. Have spoken to one rewinds company but they're unsure if can help due to size and guy I normally deal with is on holiday.

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