Abstract: A variable speed AC motor control drive system for use in devices such as treadmills and including a module to sense the voltage of the line voltage provided to the system and adjusting the pulse width modulated signals provided to the AC motor in response thereto as well as providing a module for sensing the load placed on the AC motor by monitoring the bus voltage of the system and. providing a signal representative of the load such that the duty cycles of the pulse width modulated signals are varied in accordance with the line voltage of the system and the load on the AC motor to maintain the desired motor speed.

Abstract: A current sensing module for use with a variable speed AC motor control drive system for use with devices such as treadmills and including a module to sense the current of pulse width modulated signals provided to an AC motor wherein the current sensing module includes a fast sense circuit to sense excessive current conditions in the pulse width modulated signals and a slow sense circuit to sense average current values in excess of desired values over a predetermined period of time to protect the AC motor from damage caused by the increased frictional resistance to the rotation of the walk belt on the treadmill deck as the walk belt and treadmill deck wear out.

Abstract: A variable speed AC motor control drive system for use in devices such as treadmills and including a module to sense the voltage of the line voltage provided to the system and adjusting the pulse width modulated signals provided to the AC motor in response thereto as well as providing a module for sensing the load placed on the AC motor by monitoring the bus voltage of the system and providing a signal representative of the load such that the duty cycles of the pulse width modulated signals are varied in accordance with the line voltage of the system and the load on the AC motor to maintain the desired motor speed.

Abstract: A control system controls a D.C. speed-change motor to change the transmission configurations on a treadmill transmission powered by an A.C. drive motor. The control system may be either microprocessor based or a system of discrete logical pieces. The control system responds to both the current speed of the treadmill belt and the electrical current drawn by the speed-change motor. The control system uses this information to modulate the duty cycle of voltage pulses sent to the D.C. speed-change motor to power the speed-change motor in response to a determination by the control system that the speed-change motor needs to rotate faster or slower to produce a controlled rate of speed change for the treadmill belt. The control system also includes a rapid deceleration system. In response to the user's direction or in response to the condition of the treadmill, the control system sends a high voltage to the D.C.

Abstract: A high speed deceleration device and method is disclosed that operates on a D.C. speed-change motor used to change the transmission configurations on the transmission of a treadmill powered by a constant speed drive motor. In ordinary use, normal transmission acceleration and deceleration rates are used to speed up or slow down the treadmill belt. A deceleration control signal causes a high voltage to be provided to the D.C. speed-change motor. The high voltage causes the D.C. speed-change motor to rapidly change the transmission configurations on the treadmill which causes a rapid deceleration of the treadmill belt. The deceleration control signal is produced in response to a user direction or in response to the condition of the treadmill. Once the belt has been slowed below a threshold speed, the machine shuts itself off.

Abstract: A control system controls a D.C. speed-change motor to change the transmission configurations on a treadmill transmission powered by an A.C. drive motor. The control system may be either microprocessor based or a system of discrete logical pieces. The control system responds to both the current speed of the treadmill belt and the electrical current drawn by the speed-change motor. The control system uses this information to modulate the duty cycle of voltage pulses sent to the D.C. speed-change motor to power the speed-change motor in response to a determination by the control system that the speed-change motor needs to rotate faster or slower to produce a constant rate of speed change for the treadmill belt. The control system also includes a rapid deceleration system. In response to the user's direction or in response to the condition of the treadmill, the control system sends a high voltage to the D.C.

Abstract: A chart recorder (10) is disclosed having an automatic paper loading system, an automatic tensioning system and an "odometer" system for determining the amount of paper moved through the chart recorder. The chart recorder (10) includes a print roller (34) and a feed roller (22), both in frictional contact with the paper in the recorder and both connected to and rotated by a motor. The feed roller (22) is connected to the motor through a one way clutch that allows the feed roller (22) to "free wheel" when the feed roller (22) is rotated at a faster rate, due to frictional contact with the paper, than the roller would be rotated by the motor (56). Dissipative forces in the one way clutch (68) and bearings (24) of the feed roller (22) cause it to resist being rotated which imparts tension to the paper and draws it into contact with a paper guide (14).