3 to 9W VPG … variable power generator

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Greystoke
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Re: 3 to 9W VPG … variable power generator

Postby Greystoke » 19 Jun 2018, 5:19pm

I have a bottle dynamo running 2 3w halogen lamps switched in series depending on speed.....light output with both on is more than adequate. I fitted a capacitor in the second lamp to bring it in at a lower speed.
I use this all year round on my commuter bike and have a similar setup on my tourer.
Granted a hub dynamo would have less drag and would require a different capacitor (due to more poles). One day I may upgrade........

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ConRAD
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Re: 3 to 9W VPG … variable power generator

Postby ConRAD » 20 Jun 2018, 7:21am

Greystoke wrote:... granted a hub dynamo would have less drag and would require a different capacitor (due to more poles)...

1. A different capacitor ? ... a hub dynamo output is AC as far as i know, so what's the capacitor for?
2. A hub dynamo has less poles that's true (26 approx) but due to much lower spinning rate it results in a much lower output frequency so far ... isn't it?
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Brucey
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Re: 3 to 9W VPG … variable power generator

Postby Brucey » 20 Jun 2018, 8:02am

just guessing here but maybe Greystoke is using a 'boost capacitor' as per circuits 5,6 here

http://pilom.com/BicycleElectronics/DynamoCircuits.htm

in which case the ideal capacitor rating varies with generator type.

cheers
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ConRAD
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Re: 3 to 9W VPG … variable power generator

Postby ConRAD » 20 Jun 2018, 8:12am

...but he says to be using halogen lamps!
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Greystoke
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Location: Lincolnshire

Re: 3 to 9W VPG … variable power generator

Postby Greystoke » 20 Jun 2018, 7:02pm

Hello
yes halogen lamps.
1st lamp works as normal.....the faster you go the brighter it gets until they eventually burn out due to excessive voltage. I switch in a second lamp in series with the first as I go quicker. The capacitor is in series with the second lamp, it's a bi-polar capacitor as it's working on AC.
All you need is a dynamo without a zener diode in it (a zener limits the voltage to prevent over-volting the lamps). The capacitor alters the phase angle to enable the higher voltage to come in at a lower speed than without.
I've ran bikes like this for years (nearly 30 :shock: ).....the audax people used to do this all the time, schmidt E6 primary and E6z secondary. They use a different capacitor as the schmidt hub has more poles than the bottle dynamo.

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ConRAD
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Re: 3 to 9W VPG … variable power generator

Postby ConRAD » 20 Jun 2018, 8:58pm

Greystoke wrote:... I switch in a second lamp in series with the first as I go quicker. The capacitor is in series with the second lamp ...

... so everything is in series !!! ...can't really understand how the capacitor can help !!

Greystoke wrote:... the schmidt hub has more poles than the bottle dynamo ...

...true, but its output frequency is much less !
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andrew_s
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Location: Gloucestershire

Re: 3 to 9W VPG … variable power generator

Postby andrew_s » 21 Jun 2018, 12:55am

Greystoke wrote:I've ran bikes like this for years (nearly 30 :shock: ).....the audax people used to do this all the time, schmidt E6 primary and E6z secondary.

I used to be one of them.
What's the cost of halogen bulbs these days? I used to find they needed replacing after about a year, even if they didn"t blow, having gone noticably dimmer than when new.
LEDs don't have the same running costs, as well as being brighter.

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NATURAL ANKLING
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Re: 3 to 9W VPG … variable power generator

Postby NATURAL ANKLING » 30 Jun 2018, 11:34pm

Hi,
I suppose that a dynamo, generator whatever could be used as backup to fall back on when your batteries go flat.
Leds have come on in leaps and bounds.
Bought a rear led the other day, uses two AAA.
On box it says 30hrs on one led continuous.
I had 26 hrs on rechargeables.
Defaults to flash when you connect batts.
Defaults to flash when batts get low.
£2

Moving between bikes is the biggest drawback for generators.
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Greystoke
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Re: 3 to 9W VPG … variable power generator

Postby Greystoke » 1 Jul 2018, 10:10am

I bought a load of 3w halogen bulbs cheap. I've got a pair of mr11 2w led lamps running off a dynamo, they're bright but the beam is compromised, it's symmetrical (like a car main beam) and wastes light. The best bike lights have an asymmetrical beam (like dipped on a car).

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ConRAD
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Re: 3 to 9W VPG … variable power generator

Postby ConRAD » 3 Jan 2019, 11:17am

… actually, I was just jocking … but it appears that somebody in the meantime took it seriously and, simply, “did” it!!

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SA_SA_SA
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Re: 3 to 9W VPG … variable power generator

Postby SA_SA_SA » 7 Jan 2019, 12:37pm

ConRAD wrote:… actually, I was just joking … but it appears that somebody in the meantime took it seriously and, simply, “did” it!! img...

What is that and is it for sale?
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ConRAD
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Re: 3 to 9W VPG … variable power generator

Postby ConRAD » 7 Jan 2019, 1:14pm

SA_SA_SA wrote:... what is that ...?

Well, perhaps the post above isn't clear enough !!
1. the 1st picture shows my own prototype that I did a few years ago.
2. the 2nd picture shows what a guy somewhere in the United States is trying to put into production through a crowdfunding scheme financing SPINETICSINC

In my case the system is definitely working, the rotor is fitted with permanent magnets, the stator with coils wired in series to increase voltage. One of the possible advantages compared to hub dynamo is that you do not have to disassemble and build again a complete wheel.

However, as far as I can see:

- mechanical friction is indeed exactly the same one valid for a standard hub dynamo, both so far use bearings. Friction is of course much better whether compared with other dynamos such as bottle type or spoke dynamos

- another advantage is that you can install one of them either on front or rear wheel, or on both wheels just in case you need more power

- it might come available with different output rated powers just playing on number and strength of magnets and coils arrangement

Conversely among possible critical points and disadvantages I can see
- overall design that doesn’t allow for pole-claw configuration typical of hub dynamos
- total exposure to atmosphere
- requires accurate installation to reduce to a minimum the airgap in the between rotor and stator
- possible strong axial vibrations
- weight

In my prototype:
- the output power was pretty low, yet enough to light-on at very low speed some RGB leds
- rotor-stator airgap was very big
- magnetic circuit was extremely poor (I used a steel disk brake!!)
- coils were just recycled junked relay coils

Ps: personally, my experiments are concluded, now I’m just curious to see what that guy will be able to do !!
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SA_SA_SA
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Re: 3 to 9W VPG … variable power generator

Postby SA_SA_SA » 7 Jan 2019, 2:43pm

Ah, thanks, I came across the Spinetics site a while ago but it seemed stuck, no updates, ie not yet available...
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ConRAD
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Re: 3 to 9W VPG … variable power generator

Postby ConRAD » 4 Feb 2019, 9:58pm

I’ve just put the same question on the German Forum: why to possibly conceive a new type generator we are necessarily supposed to adhere to StVZO standards?
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