Electric Motor Testing, Operation, Maintenance, Protection and Troubleshooting

Introduction

It is estimated that electrical drives and other rotating equipment consume about 50% of the total electrical energy consumed in the world today (and this figure increases to 70% if you only consider industry.) The cost of maintaining electrical motors can be a significant amount in the budget item of the manufacturing and mining industries. This course gives you a thorough understanding of electrical motor’s protection, control, and maintenance and gives you the tools to maintain and troubleshoot electrical motors. You will gain a fundamental understanding of the protection, control, and maintenance of electric motors and drives. Typical applications of electric motors in manufacturing, materials handling, process control are covered in detail. The concluding section of the course gives you the fundamental tools in troubleshooting motors confidently and effectively.

Objectives

Upon successful completion of this course, the delegates will be able to:

• Apply and gain an in-depth knowledge on electric motor maintenance and troubleshooting ·
• Specify protection requirements for motors and maintain electrical motors ·
• Identify the speed control requirements for motors and discuss the essentials of motors and drives
• Enumerate the main issues with testing of motors to prevent motor bearing failure
•  Troubleshoot and fix faults on motors and drives
• Discuss interface control circuits of motors with PLC’s/DCS’s
• Reduce downtime on electrical motors and improve plant safety · Develop plant throughput and reduce spares usage and requirements

Training Methodology

This is an interactive course. There will be open question and answer sessions, regular group exercises and activities, videos, case studies, and presentations on best practice. Participants will have the opportunity to share with the facilitator and other participants on what works well and not swell for them, as well as work on issues from their own organizations. The online course is conducted online using MS-Teams/ClickMeeting.

Who Should Attend?

This course is valuable for those associated with the use of electrical motors in the industrial or automation environment. This course will also benefit those working in system design as well as site commissioning, maintenance and troubleshooting.

Course Outline

Day 1: Introduction, Overview & Discussion of Objectives Fundamentals of Motor Technology and Construction

Basic Principles of Rotating Electric Machines

• Fundamental Principles of Speed Control
• Efficiency, Torque, Inertia, Horsepower/Power Factor
• Torque-Speed Curves
• Induction/Synchronous/Wound Rotor Types
• Basic Construction and Physical Configuration, Windings
• Principles of Operation and Performance

Three Phase Ac Induction Motors

• Components
• Theory of Operation
•  Induction Motor Design
• Duty Cycles
• Insulation and Cooling Requirements
• Starting Methods Selecting motors T
• Types of Faults, Fault Finding and Testing of AC Machines
• Testing Instrumentation

Day 2: Energy Losses and Efficiency of Three Phase AC Induction Motors

• Standards
• Types of Losses Tests for Measurement and Computation of Losses and Efficiency
• Dynamometers
• Principles of Load Application By Braking
• Torque Measurement Basics
• Types of Practical Dynamometers

Motor Failure Analysis

• Frequent Starts
•  High Inertia
• Inadequate Cooling
•  Congestion on Fan Cover
• Improper Spacing at End of Motor
• Incorrect Belt Alignment
• Solid Belt Guards
• Excessive Loading Causing Bearing Clearance Problems
• Insulation Failures
• Bearing Current Problems

Day 3:

• Testing
• Insulation Life and Resistance
• Polarization Index
• DC Hipot
• DC Ramp Test
• AC Hipot
• Capacitance Test
• Dissipation Factor
• Partial Discharge
• Surge Test
• Mechanical Testing
• Online Testing

 Bearing Failure Analysis

• Bearing Failures
• Grease and Greasing
• Belt Drive Aspects
• Balance
• Storage Issues
• Service Factor Loading
• Thermal Overload
• Time Constraints
• Early Relays and New Digital Relays
• Starting and Stalling Conditions
• Over Current / Overload
• Under-Voltage / Over-Voltage
• Protection of Motors

Day 4: Protection of Motors (Cont’d)

• Under Frequency
• Pole Slip / Out of Step
• Loss of Excitation
• Inadvertent Energization
• Over Fluxing
• Stall Protection / Acceleration Time / Start-Up Supervision /Time Between Starts
• Unbalanced Supply Voltages
• Negative Sequence Currents
• De-Rating Factors
• Earth Faults – Core Balance, Residual Stabilizing Resistors
• Calculation of Protective Relay Settings
• Motor Control
• Power Circuit
• Control Circuit
• Full Online Voltage Starting
• Reduced Voltage Starting: Delta-Star, Resistance, Reactor, Autotransformer, Soft Start
• Braking
• Speed Control
• Reversing

Day 5: Control System for AC Variable Speed Drives