Abstract: An efficient off-line rectified, high-power, AC-to-DC power supply is provided. High-power factor and minimal circuit size, cost, and complexity are achieved by combining switchmode power converter operation as well as conduction-mode operation. The switchmode power converter is controlled such that only a fraction of the output power is converted by the switchmode power converter. Peak power is efficiently conducted directly from an AC line to a DC output without requiring the operation of the switchmode power converter. Such control method results in high efficiency, yet also maintains a high-power factor with optimally sized, cost-effective switchmode power converter electronics. A complete, self-contained system is provided including a soft-start, full-wave bridge.

Abstract: Apparatus and method for electrically generating mechanical braking torque employs direct field drive incorporating an AC alternator plus a current regulator. The stator windings of the alternator are directly coupled to the field winding via a full wave rectifier and the current regulator. The invention simplifies electrical circuitry for generating braking torque, provides wide dynamic range of torque generation, limits voltages and currents to easily manageable levels, and reduces mechanical drive train requirements. The invention produces a constant power mechanical load from essentially 0 to over 1,000 watts from an alternator of the size typically used for automotive applications.

Abstract: A computer controlled exercise machine in which the user selects an exercise mode and its profile by programming the computer. Signals are produced by the program to control a resistive force producing device. Sensors produce data signals corresponding to the force applied to the actuating member of the system, velocity of movement and angular position which are continuously sampled at a high rate by a microprocessor operating under control of the program. The sampled data values are used to update and display performance results for the exercise and to compute the values of other parameters and, in some exercise modes, to control the amount of the resistive force.

Abstract: An arrangement for sensing rotational torque in an exercise machine utilizes a torque measuring collar, which is generally tubular with a flange at each end. One flange is mounted to a stationary member, such as the frame of a machine. A shaft which is to rotate when the force is applied extends through the tubular collar to a gear box which itself is mounted only to the other flange of the torque collar and is therefore freely rotatable. The flange of the collar which is mounted to the gear box attempts to rotate in response to the torque (force) applied to the machine shaft by the user. This causes the collar to rotationally deform, i.e. twist, in the area between its two flanges. This torque proportional deformation effect occurs independent of the rotation position of the shaft as it rotates either direction through continuous circular motion.