Static shunt motor crane hoist control system with anti-plugging control

Abstract

Abstract A STATIC CONTROL SYSTEM FOR THE SHUNT FIELD MOTOR OF A CRANE HOIST CONTROL HAVING A STATIC FIELD SUPPLY AND A SOLID STATE REVERSING CHOPPER SUPPLIED FROM A CONSTANT POTENTIAL BUS FOR ARMATURE CONTROL WITH A FIRST SCR CONTROLLED RESISTOR LOOP FOR 75 PERCENT SECOND QUADRANT RETARDING TORQUE AND A SECOND SCR CONTROLLED RESISTOR LOOP USABLE WITH THE FIRST ONE FOR 150 PERCENT FOURTH QUADRANT RETARDING TORQUE. BOOTSTRAP CIRCUITS MINIMIZE THE FIRING CIRCUIT POWER SUPPLY REQUIREMENTS FOR THE RESISTOR LOOPS. SOLID STATE ANTI-PLUGGING CONTROL IS INCORPORATED IN THE DIRECTION AND SPEED CONTROL CIRCUIT. LIMIT STOP BACKOUT AT REDUCED TORQUE AND SPEED IS PROVIDED FROM THE CONSTANT POTENTIAL BUS. A UNIDIRECTIONAL DIODE CIRCUIT AFFORDS AUTOMATIC FIELD ENERGIZATION FROM THE ARMATURE IN THE EVENT OF POWER FAILURE. COMMUTATING INDUCTOR ENERGY DECAYING RESISTORS ARE RELOCATED IN THE CHOPPER CIRCUIT TO PROTECT THE CHOPPER AND DIRECTIONAL SCR''S FROM INDUCED VOLTAGES DURING COMMUNICATION AND TO PROTECT THE BUS FROM A SHORT CIRCUIT IF BOTH SCR''S FAIL AS ADDED FUNCTIONS. FIELD WEAKENING AND FIELD STRENGTHENING CONTROLS ARE INCORPORATED IN THE DIRECTION AND SPEED CONTROL CIRCUIT.

Inventors

• 👤 Robert L Risberg

Bibliographic Details