| 摘要 |
<p>An improved control is provided for the tape transport motor of a battery-powered, slow-speed tape recorder typically used for producing magnetic recordings of an ambulatory patient. The recorder's tape transport means is driven by a synchronous AC motor powered from a DC (battery) supply. That DC supply, during normal operation, is voltage regulated to provide desired speed stability. That DC supply is inverted into a square wave DC current in a manner effectively providing a regulated square wave AC at twice the regulated DC voltage. Phase-shifting means connected to the inverter provide a phase-shifted square wave source necessary for the two-phase AC synchronous motor. In an improved mode of control, means are additionally provided for selectively supplying current at full battery voltage, square wave inverted and phase-shifted to the AC synchronous motor in lieu of the regulated supply voltage to provide high torque operation for selected periods of time as during "start-up" or "warm-up".</p> |
