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ASD – Adjustable Speed Drives, Motors, and Motor Protection


Course Description

This course will cover the various types of adjustable speed drive and the application of the drives.  The basic concept of how a drive works and the components that make the drive function.  We will review the advantages and disadvantages of different drives in the market. Drive application concerns and issues with drives that can occur.  Power Quality concerns with drives in a facility and impact on drives with voltage events.  We will review motors run by drives and motor protection as it relates to Article 430 in the NEC.  Over current protection devices and applications will be discussed. Single phasing of three phase motors and of the issues that occur from this occurrence.


Course Material on CD 

Presentation in Power
Point Spreadsheet for calculating voltage unbalance in three phase systems


Course Outline

  • Types of Adjustable Speed Drive (General)
  • Applications
    • Pumps Fans Blowers
    • Conveyors
    • Process Flow
      • Extrusion
      • Spinning
      • Stock Feed
  • DC vs AC Drives
  • Types of AC Speed Drive Systems (Specific)
    • Current Source
    • Variable Voltage
    • Constant Voltage
    • PWM (Pulse Width Modulation)
  • Advantages and Disadvantages
  • Power Quality and Application Concerns
    • Switching Transients
    • Voltage Sags
    • Harmonics
  • Motor Characteristics
    • Type
    • Insulation Class
    • Torque
  • Protection from Overcurrents
    • Service Factor
    • Temperature
  • Motor Circuit Requirements
  • Sizing OCPD’s (Over Current Protection Device)
    • Fuses
    • Heaters
    • Breakers
    • Solid State
  • Single Phasing Protection
    • Voltage Balance
    • Current Unbalance


Course Objectives

This course should help qualified individual understand operation of ASD and the application.  Understanding the function of drives and concepts of operation of ASD.  Qualified individual will understand drive issues in the field with different voltage events and mitigation for these events.  Drive application issues and operation will help to insure proper installation of drives.  Qualified individual should have an understanding of motor types, Article 430 for motor protection, and applications consideration for motors on drives.