| 摘要 |
<p>1,060,215. Control of D.C. motors. WESTINGHOUSE BRAKE & SIGNAL CO. Ltd. Dec. 21, 1965 [Jan. 26, 1965], No. 3306/65. Addition to 1,025,871. Heading H2J. [Also in Divisions G3 and H3] A circuit of the type described in the parent Specification, wherein a motor 1 is controlled by a switch arrangement 3 in accordance with two levels, higher and lower, of motor current, is modified by the provision of additional circuitry which ensures that the switch arrangement is not turned " on ", when the lower level of current is attained, until a predetermined " off " period has elapsed. The additional circuitry achieves this effect by acting on the multivibrator 15-20 which produces the ON and OFF pulses for the switch arrangement 3, and includes a comparator transistor 5 responsive to a motor-current signal derived from a sensor 4 and to a reference signal derived from a potentiometer 7 which may be linked with the accelerator pedal of a battery vehicle, the transistor 5 being associated with a Schmitt trigger 11 connected to the multi-vibrator.</p> |
