Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations MintJulep on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  1. BruceDiesel

    Power calculation from torque

    Tom, For your background, the trainers we are using have two types of speed vs. resistance curves - trainers based on magnetic braking have a linear curve i.e. resistance is proportional to speed, and fluid trainer which have an exponential resistance vs. speed curve. We are measuring power...
  2. BruceDiesel

    Power calculation from torque

    This ties in well with anecdotal evidence that riders report - trainers with bigger flywheels present a more "road-like" feel. These speed pulses could well be fatiguing the muscles more, the question is, how do we measure this? Given the limitations of the equipment that we are using. In my...
  3. BruceDiesel

    Power calculation from torque

    For a lot of indoor trainers, the resistance increases linearly with speed (the resistance is based on magnetic/motor principle). There are new trainers that try to mimic the outdoor situation by using a turbine immersed in fluid - to create an exponential spead vs. resistance curve. The...
  4. BruceDiesel

    Power calculation from torque

    Curt, Unfortunately I don't have access to the data samples. The sampling is performed using electronics embedded in the device and the results are transmitted. I agree, the sampling rate is more than adequate, even with the harmonics that would be present, the torque wave fundamental...
  5. BruceDiesel

    Power calculation from torque

    But surely the gearing would not impact the damping effect - since it is not introducing any form of energy storage.
  6. BruceDiesel

    Power calculation from torque

    Thinking about this further, one of the ways we could adjust the system to suit the rider is to put weights on the bicycle's wheel when it is mounted on the trainer. Changing the flywheel would not be very practical.
  7. BruceDiesel

    Power calculation from torque

    So in other words, we need to figure out a way to test the impulse-response of the system in both environments, and get them to match.
  8. BruceDiesel

    Power calculation from torque

    waross: There are five types of power meatures currently available: 1. Powertap - uses strain gauges and is effectively a hub fitted to the rear wheel of the bicycle. Torque is sampled at a rate of 70Hz, and velocity once per revolution. 2. SRM - also uses strain gauges, and replaces the front...
  9. BruceDiesel

    Power calculation from torque

    skogsgurra, to try to anser your question: Essentially we are measuring the training effect that riding at a certain power level has on the athletes body (i.e. fitness). The Funtional Threshold Power (FTP) - or power that is sustainable for 60 minutes is the baseline that is used to calculate...
  10. BruceDiesel

    Power calculation from torque

    Hi waross The discrepency is happening at what we call the Functional Threshold Power - which is the power that is sustainable for 60 minutes. Which is porbably about 20% - 30% of peak power - i.e. power produced in a sprint. At this power, the upper body is very still, and the arms are...
  11. BruceDiesel

    Power calculation from torque

    The torque curve is quite close to sinusoidal, with the dead spots happening at 12 o'clock and 6 o'clock - naturally where the rider has the least leverage. At this stage, the common theory to explain this phenomenon is rider motivation is not as good riding indoors as outdoors. However, our...
  12. BruceDiesel

    Power calculation from torque

    Okay, so I am actually wrong in saying that rms should be used to calculate average torque, then multiply Trms by speed to get average power. I don't know currently if the power meter is averaging torque first then multiplying by speed, or whether it is multiplying each torque sample by speed...
  13. BruceDiesel

    Power calculation from torque

    Hi All, I hope this is the best forum for this question - because it is not directly related to electrical motors, but I believe this would be the best place to find the answer. The problem I have actually relates to the calculation of power based on varying torque and angular velocity (on a...

Part and Inventory Search

Back
Top