PRACTICAL TROUBLESHOOTING OF ELECTRICAL EQUIPMENT AND CONTROL CIRCUITS

By SUSAN TAYLOR

CONTENTS BASIC PRINCIPLES INTRODUCTION BASIC PRINCIPLES OF ELECTRICAL MACHINES AC POWER SYSTEMS METERS USED IN TROUBLESHOOTING DEVICES, SYMBOLS, AND CIRCUITS DEVICES AND SYMBOLS ELECTRICAL CIRCUITS READING AND UNDERSTANDING ELECTRICAL DRAWINGS READING AND UNDERSTANDING LADDER LOGIC WIRES AND TERMINAL NUMBERING BASIC TROUBLESHOOTING PRINCIPLES BASIC PRINCIPLES IN USING A DRAWING AND METER IN TROUBLESHOOTING CIRCUITS CHECKS FOR CIRCUIT CONTINUITY WITH DISCONNECTED SUPPLY CHECKS FOR CIRCUIT CONTINUITY WITH LIVE SUPPLY TESTS AND METHODS TESTING DEVICES CIRCUITS ACCURATE WIRING OF CIRCUITS AND CONNECTIONS TESTS FOR INSTALLATION AND TROUBLESHOOTING TROUBLESHOOTING AC MOTORS AND STARTERS FUNDAMENTALS OF THREE-PHASE AC MOTORS FUNDAMENTAL OF SINGLE-PHASE AC MOTORS DC MOTORS MOTOR ENCLOSURES MOTOR TERMINAL IDENTIFICATION AND CONNECTION DIAGRAM MOTOR RATING AND INSULATION TYPES OPERATING A MOTOR FOR FORWARD AND REVERSE OPERATION MOTOR BRAKING METHODS MOTOR TESTINGT MEASUREMENTS USED FOR A MOTOR MOTOR FAILURES AND METHODS TO EXTEND ITS LIFE MOTOR CONTROL TROUBLE–REMEDY TABLE MOTOR STARTER CHECK CHART SWITCHES, CIRCUIT BREAKERS AND SWITCHBOARDS SWITCHES AND CIRCUIT BREAKERS OVERLOADS AND FAULT PROTECTION SWITCHBOARDS MOTOR CONTROL CENTER TROUBLESHOOTING VARIABLE SPEED DRIVES THE NEED FOR VSDS BASIC VSD POWER ELECTRONIC COMPONENTS ELECTRICAL VSDS POWER ELECTRONIC RECTIFIERS (AC/DC CONVERTERS) GATE-COMMUTATED INVERTERS (DC/AC CONVERTERS) OVERALL PROTECTION AND DIAGNOSTICS INSTALLATIONS AND COMMISSIONING POWER SUPPLY CONNECTIONS AND EARTHING REQUIREMENTS PRECAUTIONS FOR START/STOP CONTROL OF AC DRIVES CONTROL WIRING FOR VSDS COMMISSIONING VSDS TROUBLESHOOTING CONTROL CIRCUITS BASIC CONTROL CIRCUITS LADDER LOGIC CIRCUITS TWO-WIRE CONTROL THREE-WIRE CONTROL – START/STOP JOG/INCH CIRCUITS SEQUENCE START AND STOP AUTOMATIC SEQUENCE STARTING REVERSING CIRCUIT PLUG STOP AND ANTI-PLUG CIRCUITS TWO-SPEED MOTOR CONTROL OVERLOAD PROTECTION TROUBLESHOOTING EXAMPLES TROUBLESHOOTING STRATEGIES LADDER LOGIC DESIGN EXERCISE BASIC ELECTRICAL CONCEPTS IN EACH PLANT, THE MECHANICAL MOVEMENT OF DIFFERENT EQUIPMENTS IS CAUSED BY AN ELECTRIC PRIME MOVER (MOTOR) ELECTRICAL POWER IS DERIVED FROM EITHER UTILITIES OR INTERNAL GENERATORS AND IS DISTRIBUTED THROUGH TRANSFORMERS TO DELIVER USABLE VOLTAGE LEVELS ELECTRICITY IS FOUND IN TWO COMMON FORMS: AC (ALTERNATING CURRENT) DC (DIRECT CURRENT) ELECTRICAL EQUIPMENTS CAN RUN ON EITHER OF THE AC/DC FORMS OF ELECTRICAL ENERGIES THE SELECTION OF ENERGY SOURCE FOR EQUIPMENT DEPENDS ON ITS APPLICATION REQUIREMENTS EACH ENERGY SOURCE HAS ITS OWN MERITS AND DEMERITS INDUSTRIAL AC VOLTAGE LEVELS ARE ROUGHLY DEFINED AS LV (LOW VOLTAGE) AND HV (HIGH VOLTAGE) WITH FREQUENCY OF 50–60 HZ AN ELECTRICAL CIRCUIT HAS THE FOLLOWING THREE BASIC COMPONENTS IRRESPECTIVE OF ITS ELECTRICAL ENERGY FORM: VOLTAGE (VOLTS) AMPERE (AMPS) RESISTANCE (OHMS)