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#31
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Is there an updated Dynotest somewhere?
On 9/14/2017 4:43 PM, Radey Shouman wrote:
Frank Krygowski writes: On 9/14/2017 10:26 AM, Ralph Barone wrote: bob prohaska wrote: Sepp Ruf wrote: For Rob who might experience mental drag uphill from just having to see a big, heavy, non-laminated hub slowly revolving in the front wheel, the smallish Shimano DH-T780-1N, 1.5W 250mA class, might suffice[1] once he grows sick of the Soubitez. Best price I see is 96 euros a pair from CNC Hamburg on ebay, no overseas shipping available, though. http://www.ebay.com/itm/253093811841 [1] DRL does not require more than 100 lumens if you get the optics right. It's a bit puzzling how folks seem to excuse poor design in dynamo hubs when they're considerably more fanatic about optimizing every other part of a bicycle. In particular, the 3 watt standard is utterly archaic. Folks now are starting to use dynamos to power electronics, and I suspect most would opt for more than 3 watt lights if useful designs were available. I still don't understand why high-end builders like Schmidt don't use salient-pole armatures, which could be constructed from standard motor laminations (instead of the custom clawpole monolith used now). That would shorten the iron path dramatically, reducing reluctance, reduce the length of copper, reducing resistance. The performance gains can be traded for lighter weight, higher efficiency or higher power. Every motor builder in the world does it that way, why not dyamo hub builders? Maybe there _is_ a technical reason, but it certainly isn't apparent to me. The use of incandescent bulbs may have set the tradition, but it's certainly no reason to continue. At this rate I won't "get sick" of the Soubitez, I'll wear it out. bob prohaska Machine theory is a bit of a black art for me, but I suspect that the "less optimized" magnetics in hub dynamos provides the extra leakage inductance required to make it self regulate into a 12 ohm load. I fully agree that a less well regulated output plus a switching regulator could work very well with modern electronics. Is it feasible to use a switching regulator when you've got as much inductance as a typical hub dynamo? I'd have thought that causes problems. Happens all the time. Google "h-bridge", and notice all those diodes in parallel with the switching components, allowing current always to continue to circulate through some path. Typically the diodes are in the same package as the switching component, eg MOSFET. So spikes, etc. from switching inductors get to sort of bleed off through diodes? Is that the idea? Again, electronics isn't my thing. -- - Frank Krygowski |
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#32
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Is there an updated Dynotest somewhere?
On Thursday, September 14, 2017 at 2:32:12 PM UTC-7, Frank Krygowski wrote:
On 9/14/2017 4:02 PM, jbeattie wrote: As for dynos, I have to re-wire my mood light and get it up and running, maybe buy a bar mount since I no longer have a through-hole in my fork crown (such are modern CF forks on a disc bike -- and I'm not going to drill CF). That sounds to me like a big disadvantage of a CF fork: the lack of a mounting hole for a light, a front rack, or anything else. It is, but hole-less-ness is not universal. There are CF forks with through-holes -- just not on my warranty replacement CAADX. Warranty beggars cannot be choosers. At least it has fender mounts, unlike many other CX bikes.. Also, even if the clashing colors weren't a problem, I couldn't swap in the aluminum pepperoni forks from the replaced frame. Those have a 1 1/8" diameter steerer as opposed to the 1 1/4 - 1 1/8" tapered steerer and matching headtube on the new CAADX. That, BTW, is an odd taper and requires a spendy headset -- unless your wife just smashed your SuperSix on a roof rack and you can use the headset off that bike (which I did). I have no problem with bar mounted lights and always used them until I got the mood light. I haven't used a front basket since I gave up my job as Wicked Witch of the West. My go-to light at this point is a bar-mounted all-in-one L&M Urban 800 which is plenty bright notwithstanding its meager 800 lumen output and obvious inadequacy for transportational cyclist navigating MUPs. -- Jay Beattie. |
#33
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Is there an updated Dynotest somewhere?
On 9/14/2017 4:57 PM, jbeattie wrote:
On Thursday, September 14, 2017 at 2:32:12 PM UTC-7, Frank Krygowski wrote: On 9/14/2017 4:02 PM, jbeattie wrote: As for dynos, I have to re-wire my mood light and get it up and running, maybe buy a bar mount since I no longer have a through-hole in my fork crown (such are modern CF forks on a disc bike -- and I'm not going to drill CF). That sounds to me like a big disadvantage of a CF fork: the lack of a mounting hole for a light, a front rack, or anything else. It is, but hole-less-ness is not universal. There are CF forks with through-holes -- just not on my warranty replacement CAADX. Warranty beggars cannot be choosers. At least it has fender mounts, unlike many other CX bikes. Just grab a drill and put in a hole. People do it for mounting water bottle cages so no reason not to do it for lights. |
#34
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Is there an updated Dynotest somewhere?
On 9/14/2017 7:26 AM, Ralph Barone wrote:
bob prohaska wrote: Sepp Ruf wrote: For Rob who might experience mental drag uphill from just having to see a big, heavy, non-laminated hub slowly revolving in the front wheel, the smallish Shimano DH-T780-1N, 1.5W 250mA class, might suffice[1] once he grows sick of the Soubitez. Best price I see is 96 euros a pair from CNC Hamburg on ebay, no overseas shipping available, though. http://www.ebay.com/itm/253093811841 [1] DRL does not require more than 100 lumens if you get the optics right. It's a bit puzzling how folks seem to excuse poor design in dynamo hubs when they're considerably more fanatic about optimizing every other part of a bicycle. In particular, the 3 watt standard is utterly archaic. Folks now are starting to use dynamos to power electronics, and I suspect most would opt for more than 3 watt lights if useful designs were available. I still don't understand why high-end builders like Schmidt don't use salient-pole armatures, which could be constructed from standard motor laminations (instead of the custom clawpole monolith used now). That would shorten the iron path dramatically, reducing reluctance, reduce the length of copper, reducing resistance. The performance gains can be traded for lighter weight, higher efficiency or higher power. Every motor builder in the world does it that way, why not dyamo hub builders? Maybe there _is_ a technical reason, but it certainly isn't apparent to me. The use of incandescent bulbs may have set the tradition, but it's certainly no reason to continue. At this rate I won't "get sick" of the Soubitez, I'll wear it out. bob prohaska Machine theory is a bit of a black art for me, but I suspect that the "less optimized" magnetics in hub dynamos provides the extra leakage inductance required to make it self regulate into a 12 ohm load. I fully agree that a less well regulated output plus a switching regulator could work very well with modern electronics. True, but the dynamos are a holdover from the days of incandescent bulbs. There's not much incentive to change now. |
#35
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Is there an updated Dynotest somewhere?
On 9/13/2017 10:46 PM, bob prohaska wrote:
Sepp Ruf wrote: For Rob who might experience mental drag uphill from just having to see a big, heavy, non-laminated hub slowly revolving in the front wheel, the smallish Shimano DH-T780-1N, 1.5W 250mA class, might suffice[1] once he grows sick of the Soubitez. Best price I see is 96 euros a pair from CNC Hamburg on ebay, no overseas shipping available, though. http://www.ebay.com/itm/253093811841 [1] DRL does not require more than 100 lumens if you get the optics right. It's a bit puzzling how folks seem to excuse poor design in dynamo hubs when they're considerably more fanatic about optimizing every other part of a bicycle. There's little competition in dynamo hubs and an extremely limited market for higher efficiency hubs that would require different lights. If someone could build a 6W hub that could be rectified and power and charge a decent commute light then it'd be great, but most riders that need that much light for commuting have already moved on. |
#36
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Is there an updated Dynotest somewhere?
On 9/13/2017 12:19 PM, Tosspot wrote:
On 12/09/17 12:50, sms wrote: On 9/11/2017 11:59 PM, Sepp Ruf wrote: snip For Rob who might experience mental drag uphill from just having to see a big, heavy, non-laminated hub slowly revolving in the front wheel, the smallish Shimano DH-T780-1N, 1.5W 250mA class, might suffice[1] once he grows sick of the Soubitez.* Best price I see is 96 euros a pair from CNC Hamburg on ebay, no overseas shipping available, though. http://www.ebay.com/itm/253093811841 [1] DRL does not require more than 100 lumens if you get the optics right. True, but if you want a dynamo light for more than just a DRL then that won't do. I have an SP dynamo (relabeled as "Joule") on a 20" wheel on a Dahon. It's coupled to a European dynamo light with about the best optics available, but at a claimed 200 lumens it's still really only useful as a DRL, plus it does not have a flash function. What light is that? http://www.herrmans.eu/start-english/products?familyId=2209 I've had one person (hard to find many people with dynamo lights at all in the U.S.) with the super-expensive Supernova light wonder ask me about it since they wonder why their lights aren't illuminating as well despite the higher lumen rating. It's all in the optics. The Herrman's optics are especially well designed. Even at $100 it's not a cheap light though. And there's no flash function. And you have to order it from Europe of course. |
#37
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Is there an updated Dynotest somewhere?
On 11/09/17 19:40, Sepp Ruf wrote:
James wrote: On 09/09/17 18:24, Sepp Ruf wrote: bob prohaska wrote: Many years ago a fairly quantitative report on the performance of bicycle lighting dynamos was published on the Web. The link is http://www.myra-simon.com/bike/dynotest.html Most of the brands named are long gone. Is there a more modern report of similar quality to be found? I've looked and found nothing remotely quantitative, just a lot of exuberant descriptions. There seem to be a considerable number of new (mostly hub) dynamos, hopefully somebody has measured what they can do. As the more recent tests were mostly conducted "by SON's Andreas Oehler or one of his buddies," they have not met r.b.t's stringent anti-corruption criteria: https://www.cyclingabout.com/dynamo-hub-drag-lab-testing/ My SP PV8 hub dynamo has been in service for a few years now. I guess that means it's done near 30,000km already, with no issues to report. Good to hear, good for you! How many indoor/outdoor temperature cycles at 100% humidity, I don't store my bicycle indoors. how much frost, Never had icicles forming on it. road salt, I don't think we get salted roads in Australia. At least none that I am aware of. Joerg-ific Wisconsin winters has it been exposed to? None. I don't live there. We get some 100% humidity and some mornings where the temperature drops to just below zero. Does that help? Characteristics very similar to a SON, but without the price tag, ... and without the virtue-signaling at taxpayer's (and their daughters') expense, I shall add. 5 year warranty, too? Admittedly, this has lost much appeal since SON updated the construction and the entire hub needs to be sent for service. -- JS |
#38
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Is there an updated Dynotest somewhere?
On 9/14/2017 9:48 PM, sms wrote:
If someone could build a 6W hub that could be rectified and power and charge a decent commute light then it'd be great, but most riders that Think they need that much light for commuting have already moved on. IFTFY. -- - Frank Krygowski |
#39
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Is there an updated Dynotest somewhere?
On 9/14/2017 9:41 PM, sms wrote:
On 9/14/2017 7:26 AM, Ralph Barone wrote: bob prohaska wrote: Sepp Ruf wrote: For Rob who might experience mental drag uphill from just having to see a big, heavy, non-laminated hub slowly revolving in the front wheel, the smallish Shimano DH-T780-1N, 1.5W 250mA class, might suffice[1] once he grows sick of the Soubitez.Â* Best price I see is 96 euros a pair from CNC Hamburg on ebay, no overseas shipping available, though. http://www.ebay.com/itm/253093811841 [1] DRL does not require more than 100 lumens if you get the optics right. It's a bit puzzling how folks seem to excuse poor design in dynamo hubs when they're considerably more fanatic about optimizing every other part of a bicycle. In particular, the 3 watt standard is utterly archaic. Folks now are starting to use dynamos to power electronics, and I suspect most would opt for more than 3 watt lights if useful designs were available. I still don't understand why high-end builders like Schmidt don't use salient-pole armatures, which could be constructed from standard motor laminations (instead of the custom clawpole monolith used now). That would shorten the iron path dramatically, reducing reluctance, reduce the length of copper, reducing resistance. The performance gains can be traded for lighter weight, higher efficiency or higher power. Every motor builder in the world does it that way, why not dyamo hub builders? Maybe there _is_ a technical reason, but it certainly isn't apparent to me. The use of incandescent bulbs may have set the tradition, but it's certainly no reason to continue. At this rate I won't "get sick" of the Soubitez, I'll wear it out. bob prohaska Machine theory is a bit of a black art for me, but I suspect that the "less optimized" magnetics in hub dynamos provides the extra leakage inductance required to make it self regulate into a 12 ohm load. I fully agree that a less well regulated output plus a switching regulator could work very well with modern electronics. True, but the dynamos are a holdover from the days of incandescent bulbs. So is electricity in general. ;-) -- - Frank Krygowski |
#40
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Is there an updated Dynotest somewhere?
John B. wrote:
Not to argue but why is the "clawpole armature" used in automotive "alternators". -- The power output of any given electrical machine is proportional to operating frequency (within some rather broad limits). If you want high power, the easiest way to get it is using high(er) frequency. Clawpole designs are mechanically strong and relatively cheap to manufacture. http://www.rle.mit.edu/per/wp-conten...pologies-I.pdf states in part: The salient pole synchronous generator has the highest electrical output per pound per rpm among all generators according to a NASA study published in 1965 [9]. It also has the lowest reactances and therefore its regulation and transient performance are the best. bob prohaska |
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