DC Motors, Speed Controls, Servo Systems - 3rd Edition - ISBN: 9780080217147, 9781483148373

DC Motors, Speed Controls, Servo Systems

3rd Edition

An Engineering Handbook

Authors: Unknown Author
eBook ISBN: 9781483148373
Imprint: Pergamon
Published Date: 1st January 1972
Page Count: 510
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DC Motors - Speed Controls - Servo Systems: An Engineering Handbook is a seven-chapter text that covers the basic concept, principles, and applications of DC and speed motors and servo systems.

After providing the terminology, symbols, and systems of units, this book goes on dealing with the basic theory, motor comparison, and basic speed control methods of motors. The subsequent chapters describe the phase-locked servo systems and their optimization and applications. These topics are followed by a discussion of the developments made by Electro-Craft in the field of DC Brushless Motors. The final chapter provides revised data sheets on Electro-Craft products and describes the models in the motomatic range of speed controls, servomotor controls, and digital positioning systems.

This handbook is of great value to professional engineers and engineering students.

Table of Contents


Chapter 1. Terminology, Symbols, Systems of Units

1.1. Terminology

1.2. Symbols

1.3. Systems of Units

Chapter 2. DC Motors and Generators

2.1. Basic Theory

Historical Background

Concept of Torque and Power

Law of Electromagnetic Induction

Magnetic Circuit Principles

Magnetomotive Force

Magnetic Flux

Magnetic Flux Density


Magnetic Field Intensity

Working Equations for Voltage and Torque




2.2. Motor Comparison

General Description

Wound-Field Motors

Permanent Magnet Motors

2.3. Motor Equations and Transfer Function

2.3.1. Electrical Equations

2.3.2. Dynamic Equations

2.3.3. Motor Transfer Function

2.3.4. Torsional Resonance

2.3.5. Speed-Torque Curve

2.4. Power Dissipation in DC Motors

2.4.1. Origins of Power Dissipation

2.4.2. Power Dissipation

2.4.3. Dissipation at Constant Velocity

2.4.4. Dissipation During Incremental Motion

2.5. Thermal Characterisitcs of DC Motors

2.5.1. Continuous Operation

2.5.2. Intermittent Operation

2.5.3. Thermal Model

2.5.4. Thermal Equations

2.5.5. Thermal Analysis

2.6. Motor Characteristics and Temperature

Armature Resistance

Torque Constant and Voltage Constant

Derating Motor Torque

2.7. Other Characteristics



Noise and Dynamic Balancing

Noise Caused by Side Loading

Bearing Noise

Brush Noise

Environmental Considerations

Brush Wear

Motor Life

Demagnetization of PM Motors

2.8. Moving Coil Motors (MCM)

Moving Coil Motors

Moving Coil Motors and Motor Ratings

Thermal Properties

Resonant Phenomena in Moving Coil Motors

Demagnetizing Current

2.9. Specialty Motors - Permanent Magnet Motors with Variable KT

2.9.1. Introduction

2.9.2. The Wound-Field Motor

2.9.3. New Motor Types

2.10.Motor Testing

End Play

Radial Play

Shaft Runout

Moment of Inertia



Friction Torque and Starting Current

No-Load Current and Rotational Losses, No-Load Voltage, No-Load Speed

Demagnetization Current

Torque Constant

Voltage Constant

Electrical Time Constant

Mechanical Time Constant

Torque Ripple

Speed Regulation Constant


Frequency Response

Thermal Resistance

Thermal Time Constant

Air Flow Impedance

Incoming Inspection of Motors

Motor Troubleshooting Chart

2.11. DC Generators



Types of DC Generators

Mounting Features

Temperature Effects

Ultrastable Generators

Stable Generators

Compensated Generators

Uncompensated Generators

Linearity and Load Effects

2.12. Generator Testing

Output Impedance

Voltage Gradient

Voltage Polarity

Generator Ripple

Iron-Core Generator Ripple

Moving Coil Tachometer Ripple

Temperature Coefficient

Dielectric Test



Incoming Inspection

Generator Troubleshooting Chart

Chapter 3. Unidirectional Speed Controls

3.1. Basic Control Methods

Speed Controllers-An Introduction

Open Loop Controls-The Traditional Approach

Closed-Loop Controls

Speed Controls VS. Servo Systems

3.2. Velocity Control Single Quadrant Controller

Voltage and Current of A Single Quadrant Controller

System Operation

Dynamic Braking

3.3. Amplifiers

The Linear Amplifier

Torque Limiting

Dynamic Braking Devices

Reversible Speed Controls

Controlled Acceleration-Deceleration System

Switching Amplifiers

Pulse-Width Modulated Amplifiers

SCR Controls

Chapter 4. Speed Controls and Servo Systems

4.1. Servo Theory

Laplace Transformation

Inverse Laplace Transformation

Transfer Functions

Block Diagrams

Transfer Function of a DC Motor

Transfer Function of an Amplifier


Root Locus Method

4.2 Servo Components

4.2.1. DC Motor

4.2.2. Amplifier

4.2.3. Amplifier-Motor System

4.2.4. Tachometer

4.2.5. Potentiometer

4.2.6. Linear Variation Differential Transformer (LVDT)

4.2.7. Encoders

4.3. Servo Systems

4.3.1. Introduction

4.3.2. Velocity Control Systems

4.3.3. Position Control Systems

4.3.4. Torque Control Systems

4.3.5. Hybrid Control Systems

4.4. System Characteristics

4.4.1. Response of the System to a Step Command

4.4.2. System Bandwidth

4.4.3. Effect of Torsional Resonance

4.5. Servo Amplifiers

4.5.1. Linear Amplifiers

4.5.2. SCR Amplifiers

4.5.3. Switching Amplifiers

4.6. Phase-Locked Servo Systems

4.6.1. Introduction

4.6.2. System Components

4.6.3. System Design and Stability

4.6.4. Special Characteristics

4.7. How to Make Systems Work

4.8. Optimization

4.8.1. Introduction

4.8.2. Velocity Profile Optimization

4.8.3. Coupling Ratio Optimization

4.8.4. Capstan Optimization

4.8.5. Optimum Motor Selection for Incremental Application

4.9. Permanent Magnet Motors for Servo Applications

4.10. Systems and Controls Troubleshooting

Theoretical Failure-Symptom Chart

Chapter 5. Applications

5.1. Introduction

5.2. System Classification and Specification

5.2.1. Classification

5.2.2. Specification

5.3. Motor Selection Criteria

5.3.1. Introduction

5.3.2. When to Specify

5.3.3. What to Consider

5.3.4. Selection Analysis

5.4. Application of Motomatic Systems

5.4.1. Speed Range

5.4.2. Output Torque and Ambient Temperature

5.4.3. Speed Regulation and Stability

5.4.4. Motomatic Speed Control Features

5.4.5. Series E-550 Motomatic Controls

5.4.6. Series E-650 Motomatic Controls

5.5. Application Examples

Office Copying Machine

Hydraulic Motor Drives

Automatic Retrieval System

Speed-Torque Analyzer

Energy Chopper

Laboratory Stirrer

Filament Winding Machine

Rewinder Speed Control

Multi-Motor Control for Industrial Knitting Machines

Semiconductor Manufacturing Photoresist Spinner

Blood Oxygenator

Infusion Pump

Crystal Pulling Machine

Conveyor Feed Rate Control

Reflow Soldering

Drive for Disc Memory Testing

Variable Speed Tape Recorder

Motor Testing

Tachometer Ripple Voltage Testing

Torque Limiter

Paper Web Wind-Up Control

Welding Machines

Bidirectional Position Control

Muscle Exerciser - Medical Rehabilitation Device

Punch Press Feed Control

Connector Test Station

Blueprint Machine Drive

Film Scanning Device

Drive for Chart Recorder

Paper Cutting Control

Blood Cell Separator

Adjustable Lathe Feed Rate Control

Contour Lathe

Three-Axis Milling Machine Control

Linear Drive System

Phototypesetter Application

Diamond Sorting System

Printed Circuit Solder Fusing Machine

Component Marking System

5.6. Incremental Motion Applications

5.6.1. Introduction

5.6.2. Selecting the Proper Servomotor for an Incremental Motion System

5.6.3. Tag Printer Feed Drive

5.6.4. Conveyor Drive System

5.6.5. Computer Tape Transport Reel Motor

5.7. Application of P6000 Series Servo Motor Systems

5.7.1. General Description of the P6000 Range of Servo Motor Controls

5.7.2. Standard Options

5.7.3. Standard Drive Packages

5.7.4. Amplifier Installation

5.7.5. Control Adjustments

5.7.6. Customer Connections

5.7.7. Summing Amplifier Compensation

5.7.8. Ramp Generator Adjustment

5.7.9. In Case of Difficulty

5.7.10. Troubleshooting Guide

Chapter 6. Brushless DC Motors

6.1. Introduction

6.2. Definition of a Brushless DC Motor System

6.3. Practical Solutions to Brushless Commutation

6.4. Torque Generation by Various Controller Configurations

6.4.1. The Sinusoidal Control Scheme

6.4.2. Trapezoidal Torque Function

6.5. Commutation Sensor Systems

6.6. Power Control Methods

6.7. Motor Constants

6.8. Brushless DC Tachometers

6.9. Examples of Brushless Motors

6.10. Summary

6.11. Step Motors Versus Brushless DC Motors in Digital Position Systems

6.11.1. Introduction

6.11.2. Step Motor Performance Limitations

6.11.3. Brushless DC Motor Incremental Motion Control

6.11.4. Conclusion

Chapter 7. Electro-Craft Corporation Products

7.1. DC Servomotors






7.2. Servomotor Generators








7.3. Moving Coil Motors








7.4. Tachometers-Generators



7.5. Special Hybrid Motors

H-5200 Series

7.6. Servomotor Controls and Systems

7.6.1. Motor Speed Controls

7.6.2. P6000 Pulse Width Modulated DC Servomotor Controllers

7.6.3. SD6 Series Servo System Packages

7.6.4. L5000 Linear Servomotor Controls

7.6.5. Options for Use With P6000 and L5000 Controls

7.7. Brushless DC Motors

BLM 340

BLM 341

BLM 342

7.8. Servo Systems for Engineering Education

Motomatic Control System Laboratory (MCSL)

Motomatic Experimenter


A.1. SI System of Units Metric System

Definition of Basic SI Units




Electric Current

Temperature Difference

Review of Main SI Units and Secondary Units

Mechanical Units

Electrical and Magnetic Units

A.2. Units' Conversion Factors and Tables

Conversion Factors

Torque-Power-Speed Nomograph

Moment of Inertia Conversion Factors

Torque Conversion Factors


Relationship of the Speed, Torque and Output Power of a Motor

Inches to Millimeters Conversion

Celsius to Fahrenheit Degrees




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