ELECTRICAL MOTOR CONTROL TROUBLE SHOOTING TECHNIQUES

OVERVIEW

Description

Maximum efficiency, reliability, and longevity of electrical motor such as the various types of motors, variable-speed drives, rewinding of most types of motors. These objectives can only be achieved by understanding the characteristics, selection criteria, common problems and repair techniques, preventive and predictive maintenance. This course is a MUST for anyone who is involved in the selection, applications, or maintenance of electrical motors. It provides the latest in technology. The course covers how these motors operate and provide guidelines and rules that must be followed for a successful operation. Their basic design, operating characteristics, rewinding, specification, selection criteria, critical components as well as all maintenance issues are covered in detail.

Objective

  • To provide a comprehensive understanding of the various types of motors, variable-speed drives. Participants will be able to select, commission and maintain these motors for their applications.
  • To achieve reduced capital, operating and maintenance costs along with increase in efficiency.

Who should Attend

Engineers of any discipline, managers, technician, technologists, and other technical personnel.

COURSE OUTLINE

Day – One

Fundamentals of Electric Systems

  • Capacitors
  • Current and Resistance
  • The Magnetic Field
  • Faraday’s Law of Induction
  • Lenz’s Law
  • Inductance
  • Alternating Currents
  • Three-Phase System

Introduction to Machinery Principles

  • Electric Machines and Transformers
  • Common Terms and Principles
  • The Magnetic Field
    • Production of a Magnetic Field
  • Magnetic Behavior of Ferromagnetic Materials
    • Energy Losses in a Ferromagnetic Core
  • Faraday’s Law – Induced Voltage From a Magnetic Field Changing with Time
  • Core Loss Values
  • Permanent Magnets
  • Production of Induced Force on a Wire
  • Induced Voltage on a Conductor Moving in a Magnetic Field
Day – Four

Synchronous Machines

  • Physical Description
  • Pole Pitch: Electrical Degrees
  • Airgap and Magnetic Circuit of a Synchronous Machine
  • Synchronous Machine Windings
  • Field Excitation
    • Rotating Rectifier Excitation
    • Series Excitation
  • No-Load and Short-Circuit Values
  • Torque Tests
    • Speed-Torque Characteristic
    • Pull-In Torque
    • Pull-Out Torque
  • Excitation of a Synchronous Machine
  • Machine Losses
    • Windage and Friction Loss
    • Core Losses
    • Stray-Load Loss
    • Armature Conductor Loss
    • Excitation Loss
Day – Two

AC Machine Fundamentals

  • The Rotating Magnetic Field
    • Proof of The Rotating Magnetic Field Flux Concept
    • The Relationship between Electrical Frequency and The Speed of Magnetic Field Rotation
    • Reversing The Direction of the Magnetic Field Rotation
  • The Induced Voltage in AC Machines
    • The Induced Voltage in a Coil on a Two-Pole Stator
    • The Induced Voltage in a Three-Phase Set of Coils
    • The RMS Voltage in a Three-Phase Stator
  • The Induced Torque in a Three-Phase Machine
  • Winding Insulation in AC Machines
  • AC Machine Power Flow and Losses

Induction Motors

  • Induction Motor Construction
  • Basic Induction Motor Concepts
    • The Concept of Rotor Slip
    • The Electrical Frequency of the Rotor
  • The Equivalent Circuit of an Induction Motor
    • The Rotor Circuit Model
  • Losses and The Power-Flow Diagram
  • Induction Motor Torque-Speed Characteristics
    • Comments on The Induction Motor Torque-Speed Curve
    • Variation of The Torque-Speed Characteristics
  • Control of Motor Characteristics By Squirrel-Cage Rotor Design
    • Deep Bar and Double-Cage Rotor Designs
  • Starting Induction Motors
    • Induction Motor Starting Circuits
Day – Five

Speed Control of Induction Motors

  • Speed Control by Changing the Line Frequency
    • 2.0 Speed Control by Changing the Line Voltage
    • 3.0 Speed Control by Changing the Rotor Resistance
    • 4.0 Solid-State Induction Motor Drives
    • 5.0 Motor Protection
    • 6.0 The Induction Generator
  • Induction Generator Operating Alone
    • 7.0 Induction Motor Ratings

Vibration Analysis

  • The Application of Sine Waves to Vibration
  • Multimass Systems
  • Resonance
  • Logarithms and Decibels (db)
  • The Use of Filtering
  • Vibration Instrumentation
  • Displacement Transducer (proximity probe)
  • Velocity Transducer
  • Acceleration Transducer
  • Transducer Selection
  • Time Domain
  • Frequency Domain
  • Machinery Example
  • Vibration Analysis
  • Vibration Causes
  • Forcing Frequency Causes
  • Unbalance
  • Misalignment
  • Mechanical Looseness
  • Bearing Defects
  • Gear Defects
  • Oil Whirl
  • Blade or Vane Problems
  • Electric Motor Defects
  • Uneven Loading
  • Drive-Shaft Torsion
  • Resonant Frequency
  • Vibration Severity
Day – Three

Maintenance of Motors

  • Characteristics of Motors
  • Enclosures and Cooling Methods
  • Application Data
  • Design Characteristics
  • Insulation of AC Motors
  • Failures in Three-Phase Stator Windings
  • Predictive Maintenance
  • Motor Troubleshooting
  • Diagnostic Testing for Motors
    • Stator Insulation Tests
    • DC Tests For Stator and Rotor Windings
    • Insulation and Polarization Index
    • Test Setup and Performance
    • Interpretation
    • DC High-Potential (Hipot) Testing
    • Surge Testing
    • Terminal-to-Terminal Resistances (winding resistances)
    • Tests for the Detection of Open Circuits in Induction Motor Cage Windings
    • Stator Current Fluctuation Test
    • Manual Rotation Test
  • Repair and Refurbishment of AC Induction Motors
    • Stator Work
    • Rotor Work
    • Bearings
    • Oil and Water Heat Exchangers
    • Temperature Detectors
    • Motor Repair
    • Motor Rewind
  • Failures in Three-Phase Stator Windings
  • Case Study 1: Rewinding of Motors; to show the participants how the motors been rewind. Also to let the participants to do by them selves the rewinding of most types of motors.