Bacon & Thomas, PLLC
Speed regulating circuit for motor of power coping saw
 A speed regulating circuit for a motor of a power coping saw includes a DC voltage circuit, a manual speed regulating circuit, a feedback controlling circuit and a motor driving circuit. The DC voltage circuit includes a diode, a resistor, a capacitor, and a Zener diode. The manual controlling circuit includes a Zener diode and a resistance. The feedback controlling circuit includes an amplifier, a transistor, a pulse transformer. The motor driving circuit includes an SCR and a diode. The manual controlling circuit may first be set with a reference voltage signal corresponding to the intended rotational speed of the motor. The reference voltage signal is sent to the feedback controlling circuit to get a rotational speed controlling signal of a motor with respect to the variation of loads. A DC current is then supplied to the motor driving circuit for constantly rotating the DC motor despite the variation of the load. 
G Y H H
G05B Y10T H02P H02P
additional additional inventional inventional
Chin-Chin
Chang