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03/13/12 10:24
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#186644 - Competitive bicycling
Responding to: Per Westermark's previous message
What is discussed as being measured here is the power that is transmitted. Whenever power transmission is involved, a case that is familiar to all EEs is that of power transmission lines. For example, shunting a battery will just heat the battery because of its internal resistance. We also know that if the load is matched to battery and transmission line that maximum power is transmitted to the load. The bicycle is no different.

When measuring the power transmitted, we do not have any idea of how much power can be generated without knowing the power that is reflected because a human body might be able to dynamically change themselves so that the generator is more matched to the load. The gear train gets a person close to matched. For example, when at a dead stop a low gear will allow forward movement easily and a high gear is just very hard to get moving.

That being said, gearing alone is one way to improve power transmission by matching the generator, line, and load. This is not the end yet because proper seat adjustment is also necessary so that the human body can properly transmit power to the pedals, otherwise there could also be a mismatch. On top of this, if you use the ball of your foot on the pedals, one can learn how to distribute the forces so that they are more matched to the line and load.

Given this information, a person capable of creating 1KW of power may only be able to transmit 200W if they are unfamiliar with the use of the bicycle, but a person capable of 750W may be able to transmit more than 200W because they are familiar with mechanics of how their body interacts with the machine.

So, in reality the bicycle is not as efficient as it may sound because the generator is not always matched to the line and load. Coming up with a machine that is capable of delivering most of the power the load would be very dramatic in the form of human powered vehicles and may make transportation based on petroleum a thing of the past.

List of 61 messages in thread
TopicAuthorDate
bikey design challenge      Jez Smith      03/09/12 12:14      
   Only 400W?      Per Westermark      03/09/12 12:23      
      Its a bit different on the road      Jez Smith      03/09/12 12:34      
         Brilliant idea in the bath      Jez Smith      03/09/12 13:35      
            Might work      Per Westermark      03/09/12 13:51      
               well...      Jez Smith      03/09/12 14:33      
                  So you are yourself saying 400W is a bit low max scale      Per Westermark      03/09/12 14:43      
                     O.K then 500 watts      Jez Smith      03/10/12 00:56      
                        Battery      Per Westermark      03/10/12 05:11      
            Fun with strain gauges      Oliver Sedlacek      03/12/12 05:57      
         You sure?      Per Westermark      03/09/12 13:48      
   nice ride      Andy Peters      03/09/12 14:31      
      fanks      Jez Smith      03/10/12 00:54      
   Sigma Rox 9.1...      Kai Klaas      03/10/12 09:59      
      Sigma fake      Per Westermark      03/10/12 11:07      
         What do you expect for that price?      Kai Klaas      03/10/12 12:09      
            Head or tail wind? Or riding in a group or alone?      Per Westermark      03/10/12 12:38      
               Way overcomplicating this      Joseph Hebert      03/10/12 14:02      
                  Sensors      Steve M. Taylor      03/10/12 14:22      
                     how indeed      Andy Peters      03/11/12 12:37      
                  Wrong - you are totally missing the drag factor      Per Westermark      03/10/12 14:22      
                     Not at all.      Joseph Hebert      03/10/12 16:03      
                        Real manufacturers haven't found your idea simple...      Per Westermark      03/10/12 17:09      
                           Point made      Joseph Hebert      03/10/12 18:46      
                           Some of your points are just wrong      Justin Fontes      03/10/12 19:04      
                              Sounds like you expect an infinite acceleration      Per Westermark      03/11/12 06:49      
                                 Repeat post Ignore      Justin Fontes      03/11/12 11:39      
                                 I try for a constant power      Justin Fontes      03/11/12 11:52      
                                    Crank rpm - not back wheel rpm      Per Westermark      03/12/12 00:31      
                                       I got the two confused      Justin Fontes      03/12/12 10:37      
                                          Bandwidth + return channel      Per Westermark      03/12/12 12:07      
                        Oh dear, so many variable constants      Oliver Sedlacek      03/12/12 06:48      
                  rocket science      Maarten Brock      03/11/12 03:58      
                     So don't ignore them      Joseph Hebert      03/11/12 07:39      
                        Of course, it is...      Kai Klaas      03/11/12 08:18      
                           wireless      Joseph Hebert      03/11/12 08:36      
                              Costs...      Kai Klaas      03/11/12 12:59      
                                 cost      Joseph Hebert      03/11/12 13:39      
                                    Another problem      Joseph Hebert      03/12/12 21:14      
                                       This was addressed earlier      Justin Fontes      03/12/12 22:02      
                                       Multiple strain gauges      Per Westermark      03/13/12 00:53      
                                          Competitive bicycling      Justin Fontes      03/13/12 10:24      
                                             Pulse      Per Westermark      03/13/12 10:55      
                                                If I had the power meter      Justin Fontes      03/13/12 11:14      
                                                   Normalizing with heart beats cancels some errors      Per Westermark      03/13/12 12:39      
                                                      Just to get some data to look at      Jez Smith      03/15/12 03:37      
                                                         Jez ?      Steve M. Taylor      04/14/12 04:35      
                                                            Oh Noes!!!!!!      Jez Smith      04/14/12 10:58      
                                                            The plan is      Jez Smith      04/15/12 01:55      
                                                               Brum doesn't HAVE mountains      Steve M. Taylor      04/15/12 14:51      
                                                                  Ah yes but no but      Jez Smith      04/15/12 23:23      
                                                                  Actualy...      Jez Smith      04/15/12 23:35      
                                                   If I had a power meter...      Oliver Sedlacek      04/16/12 04:20      
                                                      Ive been testing things      Jez Smith      04/16/12 04:41      
                                                         Well, no      Steve M. Taylor      04/16/12 07:41      
                                                            all very well thank you Steve      Jez Smith      04/16/12 08:45      
                                                               Getting nasty      Steve M. Taylor      04/17/12 10:54      
                                                                  nasty ?      Jez Smith      04/20/12 12:09      
                                 More time than money if access to machinery      Per Westermark      03/12/12 00:57      
                                 Strain gauge elastic fixtures      Oliver Sedlacek      03/12/12 06:55      
                           Sure      Per Westermark      03/11/12 09:42      

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