GEAR FOR CONTROL OVER REVERSIBLE ASYNCHRONOUS ELECTRIC MOTOR Russian patent published in 1994 - IPC

FIELD: electrical engineering. SUBSTANCE: with short-time pressing on button with contacts 7 and 9 contact 9 makes and contact 7 breaks, for instance. With making of contact 9 of button there is formed circuit: first phase, diode 13, resistor 14, light emitter of optron 12, contact 9, second bus of power supply source for passing of current of positive half-wave of supply voltage which leads to charging of capacitor 15 and excitation of light emitter of optron 12. Phototriac of optron 12 is held open independent of condition of contacts of limit switches 5 and 6 and of coils 1 and 2 of contactors. Power contacts of coil 2 switch on electric motor drive in forward direction of rotation. As contacts 3 of contactor with coil 2 are open contactor with coil 1 is deenergized. With pressing on button with contacts 10 and 8 power supply circuit of contactor with coil 2 is deenergized and its auxiliary contacts 3 close. Contactor with coil 1 is energized and electric motor drive rotates in reverse direction. Switching off of any of contactors is accomplished by short-time pressure of control button 11. Time constant of discharge circuit of capacitor 15 should lie within the limits of one-two periods of supply voltage. Gear provides for control over electric motor drive not only with the aid of control buttons but with the use of limit switches 5 and 6 which accomplish automatic reversal of electric motor drive with action on any of them with driving mechanism. EFFECT: improved reliability of control over technological processes. 1 dwg