| 摘要 |
<p>Circuit providing protection against mechanical overloads for dc motors. The circuit is especially for motors operating vehicle windows and provides a reversal of the motor operation if the glass movement is interrupted. The circuit is relay based and driven from a transistor and resistor bridge arrangement. Mechanical obstruction is detected by the voltage level across a resistor in series with the motor supply, the resistor preferably being a printed circuit positive temperature coefficient type. Sensitivity can be adjusted by a potentiometer across the first of four transistors a zener diode stabilising the bias circuit. A CR loop prevents motor reversal in the course of momentary obstruction of window movement.</p> |
