METHOD OF AND DEVICE TO CONTROL BRAKE ELECTRIC MOTOR OF ELECTRIC DRIVE OF TRAVELING-GRATE SINTERING MACHINE Russian patent published in 2004 - IPC

FIELD: metallurgy; sintering plants.

SUBSTANCE: according to proposed invention armature current control system is adjusted to maintain constant current of motor at changes of load and speed of traveling-grate sintering machine corresponding to maximum torque from weight of sintering cars. To decrease additional load on bead motor caused by excessive brake torque and to stabilize operating conditions of electric drive of traveling-grate sintering machine. Armature circuit of brake electric motor is powered from separate nonreversible thyristor converter operating as inverter. Minimum value of emf of thyristor converter is limited at level corresponding to difference in emf of brake electric motor at preset speed of traveling-grate sintering machine and voltage drop relative to preset value of current in armature circuit. Field currents of head and brake electric motors are maintained constant regardless of changes of temperature of their windings and supply voltage. Device for implementing the method contains control system with rigid negative armature current feedback of electric motor which consists of stabilized current supply source of electric field winding and separate nonreversible thyristor converter assembled into single-phase bridge rectifying circuit. Said thyristor converter contains single-phase saturable magnetic amplifier and pulse shaper using single channel relaxation oscillator circuit on unijunction transistor with RC-circuit and two pulse transformers operating in antiphase. Primary windings of impulse transformer are connected trough thyristor switch to output if relaxation oscillator. Two secondary windings of each impulse transformer are connected to control junctions of pair of simultaneously operating thyristors of thyristor converter. Supply of control circuits is provided with rectified voltage of trapezoidal waveform with amplitude limited by resistor and stabilized by voltage stabilizing diode connected through rectifier bridge and synchronized with supply circuit of thyristor converter. Emitter-collector of emitter repeater connected in series with capacitor of RC-circuit and voltage divider are connected to output of magnetic amplifier through isolation diode. One of resistors of voltage divider is connected to input of emitter repeater, and speed setting voltage of traveling-grate sintering machine is applied to other part of other resistor.

EFFECT: reduced additional load on head electric motor caused by excessive brake torque and stabilization of operating conditions of electric drive of traveling-grate sintering machine.

3 cl, 2 dwg