A Bicycle Ergometer with an Electric Brake

By Francis G. Benedict and Walter G. Cady18963 chapters17 images

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Contents

• Part I. Introduction (opens in a new tab)

  Benedict and Cady review earlier attempts to measure the mechanical efficiency of the human body, then describe the second Nutrition Laboratory bicycle ergometer built by W. E. Collins in 1911, its electro-magnet and 40.5 cm copper brake disk, and the calorimetric method used to calibrate it.
• Part II. Calibration Tests (opens in a new tab)

  Reports calorimetric calibration of Ergometers I and II in the Wesleyan respiration calorimeter and the Nutrition Laboratory chair calorimeter, tabulating heat produced per pedal revolution at magnetizing currents from 0.70 to 1.50 amperes, plus friction tests made with the magnet unexcited.
• Part III. The Magnetic Reactions Produced by a Copper Disk Rotating Between the Poles of a Magnet (opens in a new tab)

  Cady measures the eddy-current field across the air-gap with a bismuth spiral, compares the observed "counter flux" with theory, and draws from it practical principles for designing efficient electric brakes.