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Armature Winding and Motor Repair in DC and AC Machines

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Armature Winding and Motor Repair in DC and AC Machines

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$7.95


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Originally published in 1920, this classic electrical engineering book contains practical information and data covering winding and reconnecting procedure for direct and alternating current machines, compiled for electrical men responsible for the operation and repair of motors and generators in industrial plants and for repairmen and armature winders in electrical repair shops.

"When called upon to locate troubles in motors and generators, electricians and repairmen whose experience in this kind of work has been limited often find themselves wondering just what to do first. It is from just this viewpoint that the information on winding procedure and the hunting and correcting of troubles has been presented. That is, instead of discussing the fundamentals involved in any method of working out a repair problem, the actual problem or job as the case may be is discussed from the "how-to-do-it" standpoint. Then for each individual operation or procedure the applications of fundamental laws and rules are worked out. Considerable repetition of some details of similar methods will therefore be discovered in connection with information covering such procedure as the rewinding of machines of the same class but of different types. This has been considered advisable since a repairman should not be required to study a complete volume when details and information are desired at anyone time on the procedure for a particular type of winding for a particular design of machine."

In this book, "readers will find answers to practically all armature winding questions and solutions of many of the repair problems that they will meet in practical work. The diagrams are clear and easily followed by the shop man and run in synchronism with the text. Theory with mathematical considerations have been resorted to only in a very few cases so that the reader of the book can make use of the information and understand the discussions of all phases of armature winding even though he may have only a limited knowledge of mathematics."

Contents Covered:

  • Preface
  • Introduction
  • Direct-Current Windings
    • Action of a Commutator
    • Types of DC Armature Windings
    • Winding Parts and Terms
    • Armature Conductor or Inductor
    • Winding Element or Section
    • Armature Coils
    • Winding Pitch or Coil Pitch
    • Front and Back Pitch
    • Full Pitch and Fractional Pitch Coils
    • Symbols Used in Winding Formulas
    • Numbering Coil Sides in Armature Slots
    • Lap -- Multiple or Parallel Windings
      • Formulas for Lap Windings
      • Multiplex, Single, Double and Triple Windings
      • Meaning of the Term Reentrant
      • Multiplex Lap Windings
    • Wave -- Series or Two-Circuit Windings
      • Formulas for Wave Windings
      • Multiplex Wave or Series-Parallel Windings
      • Formulas for Series-Parallel Windings
      • Symmetrical Windings
    • Possible Symmetrical Windings for DC Machines of Different Numbers of Poles
    • Equipotential Connectors
    • Best DC Windings for a Repair Shop to Use
    • Number of Armature Slots
    • Voltage between Commutator Segments
    • Number of Commutator Bars
    • Usual Speeds and Poles of Different Sizes of Generators
    • Safe Armature Speeds
  • Alternating-Current Windings
    • Types of AC Windings
    • Distributed Windings
    • Concentrated Windings
    • Spiral or Chain Windings
    • Lap and Wave Windings
    • Whole-Coiled and Half-Coiled Windings
    • Single-Phase and Polyphase Windings
    • Coil Pitch
    • Phase Spread of Winding
    • Two-Phase from Four-Phase Windings
    • Three-Phase from Six-Phase Windings
    • Wire, Strap and Bar Wound Coils
    • Methods of Laying out and Connecting AC Windings
      • Group Windings
      • Full and Fractional Pitch Windings
      • Simple Winding Diagram
      • Reconnecting a Winding
      • Simple Method for Indicating Polarity of Coil Groups
      • Changing Star to Delta Connection
      • AC Wave Windings
      • Progressive and Retrogressive AC Wave Windings
      • Connections for Coils of Polyphase Windings
      • Double-Layer Winding, Lap Connected
      • Connecting a Chain Winding
      • Other Common Windings
    • Easily Remembered Rules for Arrangement of Coils in an Induction Motor
    • Simple Rules for Checking Proper Phase Relationship in Two- or Three-Phase Windings
  • Repair Shop Methods for Rewinding DC Armatures
    • Dismantling a DC Armature
    • Winding Data Needed for a Dismantled Armature
    • Removing Old Coils
    • Winding DC Armatures Having Partially Closed Slots
      • Winding a Threaded-in Coil
      • Insulating Lining for Slots
      • Inserting Coils in the Slots
      • Insulating Overlapping End Connections of Coils
      • Connecting Finish Ends of Coils to Commutator
      • Loop Windings for Small Motors
    • Winding DC Armatures Having Open Slots
      • Winding and Insulating Coils
      • Insulating Open Slots
      • Inserting Coils in Open Slots
      • Shaping End Connections
      • Truing up the Heads of the Winding
      • Insulation between Commutator End Connections
    • Winding Large DC Armatures
      • Coils for Large DC Armatures
      • Lap and Wave Windings for Large Armatures
      • Insulating the Core
      • Inserting the Coils
      • Banding Wire
      • Balancing Large Armatures
      • Rotary Converters
      • Three-Wire Generators
    • Winding Railway, Mill and Crane Types of Armatures
      • Railway Type Armature Coils
      • Coil Insulation
      • Insulating the Core of Railway Armatures
      • Inserting the Coils
      • Connections with Dead Coils
      • Hooding and Banding
  • Making Connections to the Commutator
    • Locating First Connection to Commutator
    • Testing out Coil Terminals
    • Commutator Connections for a Lap Winding
    • Requirements of a Lap Winding
    • Commutator Connections for a Wave Winding
    • Locating First Connection to Commutator for a Wave Winding
    • Requirements for a Wave Winding
    • Progressive and Retrogressive Wave Windings
    • Wave Winding with Dead Coils
    • Cutting out Coils of a Retrogressive and Progressive Wave Winding
    • Tables for Placing Coils and Connecting Them in a DC Winding
    • Wave vs. Lap Windings
    • Lap Windings for DC Armatures
    • Lap Windings for AC Machines
    • Wave Windings for DC Armatures
    • Wave Windings for AC Machines
    • Single vs. a Number of Independent Windings
    • Lap Windings vs. Multiple Wave Windings
    • Use of Equalizer Rings
  • Testing Direct-Current Armature Windings
    • Causes of Short Circuits in an Armature
    • Test for Short Circuits in an Armature
    • Testing for Short Circuits and Open Circuits with a Small Transformer
    • Causes of Open Circuits in an Armature
    • Tests for an Open Circuit in an Armature
    • Cutting out Injured Coils
    • Causes of Grounds in an Armature
    • Tests for Grounds in an Armature
    • Use of a Bar Magnet and Millivoltmeter to Locate a Reversed Armature Coil
    • Use of a Compass to Locate a Reversed Armature Coil
    • Locating Low Resistance or Dead Grounds
    • Use of a Telephone Receiver in Testing for Short Circuits, Open Circuits and Grounds
    • Testing for Reversed and Dead Field Coils
    • The Commutator
    • Testing Equipment for a Repair Shop
  • Operations Before and After Winding DC Armatures
    • Stripping off an Old Winding
    • Cleaning and Filing Slots
    • Testing Commutator
    • Making New Coils
    • Forms for Winding Coils
    • Insulation of Core and Slots
    • Testing out the Winding
    • Soldering Coil Leads to the Commutator
    • Hoods for Armatures
    • Banding Armatures
    • Seasoning and Grinding a Commutator
    • Undercutting Mica of a Commutator
    • Balancing an Armature
    • Painting the Winding
    • Relining Split Bearings
  • Insulating Coils and Slots for DC and AC Windings
    • Insulation for Armature Coils and Slots
      • For Mechanical Protection and Electrical Insulation
      • For High Temperatures and Electrical Insulation
      • For Electrical Insulation Only
    • Descriptions and Uses of Insulating Materials
      • Treated Cloths
      • Pressboards, Fibres and Papers
      • Coil and Slot Insulation Used in One Large Repair Shop
      • Micartafolium
    • Thickness of Insulation Required in Slots
    • Insulation of Formed Coils
    • Insulation for Coils Used in 240-Volt and 500-Volt DC Machines
    • Coil Insulation for Induction Motor Windings
    • Coil and Slot Insulation Employed by a Large Manufacturer
    • Insulation of End Connections of Coils
    • Phase Insulation When Reconnecting from 2-Phase to 3-Phase
    • Mica Insulation for Armature Coils
    • Repairing Coils Damaged in Winding Process
    • Voltage to Use When Testing Coil and Commutator Insulation
    • Field Coil Insulation
    • Varnishes and Impregnating Compounds for Coils
    • Characteristics of Insulating Varnishes
    • Solvent Chart for Insulating Varnishes
    • Method for Making Tape from Cotton Cloth
    • Drying out Insulation of DC Generators
    • Drying out Insulation of Synchronous Motors
    • Drying out Induction Motors
    • Measuring Insulation Resistance
  • Repair Shop Methods for Rewinding AC Machines
    • Winding Small Single-Phase Motors
      • Insulating Lining for Slots
      • Winding the Skein Coil
      • Inserting Skein Coil in Slots
      • Winding for a Repulsion-Start Motor
      • Winding Small Motors by Hand
      • Windings for Odd Frequencies
      • Connections for Main and Starting Windings
      • Testing Small Induction Motor Windings
      • Windings for Small Polyphase Induction Motors
    • Winding Small Induction Motors with Formed Coils in Partially Closed Slots
      • Insulation for Slots
      • Basket Coils
      • Winding a 3-Phase Stator with Basket Coils
      • Threaded Diamond Coil
      • Winding a 3-Phase Stator with Diamond Coils
    • Winding Induction Motors Having Open Slots
      • Winding a 2-Phase Stator Having Open Slots
      • Testing the Windings
      • Inserting a New Coil in a Winding
      • Connecting the Coils
      • Points to Consider When Connecting Coils
      • Cleats and Terminals
      • Painting Winding
    • Induction Motor Secondaries
      • Squirrel-Cage Secondaries
      • Phase-Wound Secondaries
    • Winding Large Alternating Current Stators
      • Coils for Partially Closed Slots
      • Coils for Open Slots
      • Lap and Wave Connections
      • Insulation of Coils
      • Inserting Shoved Through Concentric Coils
      • Bar and Connector Winding
      • Diamond Coils
      • Double Windings
      • Testing Windings of Large Machines
      • Connecting the Coils
      • Bracing Needed for Heavy Windings
    • Winding the Stator of Alternating Current Turbo-Generators
      • Coils for AC Turbo-Generators
      • Forming the Coils
      • Insulation for Turbo-Generator Coils
      • Testing Turbo-Generator Windings
      • Inserting the Coils in a Turbo-Generator
      • Bracing for Windings
      • Connecting the Winding
      • Break-down Test
  • Testing Induction Motor Windings for Mistakes and Faults
    • Testing for Grounds and Short-Circuits
    • Reversal of One or More Coils or Groups
    • Open Circuits
    • Placing Wrong Number of Coils
    • Using an Improper Group Connection
    • Order in Which Tests Should be Made
    • Connecting for the Wrong Number of Poles
    • Applying Direct Current and Exploring with a Compass
  • Adapting Direct-Current Motors to Changed Operating Conditions
    • Changes in Speed
    • Changes in Operating Voltage
    • Operating a Motor on One-Half or Double Voltage
    • Size of Wire for DC Armature Coils
    • Operating a Generator as a Motor and Vice Versa
    • Motor Speed When Reconnecting a DC Motor Winding Wave to Lap
    • Adjusting the Air Gap on Direct-Current Machines
    • Change in Brushes When Reconnecting DC Motor from a Higher to a Lower Voltage
    • Rewinding and Reconnecting DC Armature Windings fur a Change in Voltage
      • Reconnecting a Lap Winding
      • Reconnecting a Wave Winding
      • Reconnecting Duplex Windings
  • Practical Ways for Reconnecting Induction Motors
    • Points to Consider before Making Reconnections
    • Diagrams for Different Changes of Connections
    • Diagrams for Three-Phase Motors
    • Use of Table of Connections
    • Two-Phase Diagrams
    • Meaning of the Term Chord Factor
    • Phase Insulation
    • Reconnecting Motors to Meet New Conditions
      • Procedure When Considering a Reconnection of Windings
      • Practical Example for Reconnection
      • Changes in Voltage only with all Other Conditions Remaining the Same
      • Changes of Phase Only
      • Changes in Frequency
      • Changes in Number of Poles
      • Testing a Reconnected Winding
    • Effects of High and Low Voltage on Motor Operation
    • Operating Standard AC Motors on Different Voltages and Frequencies
    • Factors which Limit a Change in Number of Poles of an Induction Motor
    • Single-Circuit Delta and Double-Circuit Star Connections
    • Cutting out Coils of an Induction Motor
    • Procedure When Connecting Coils of an Induction Motor Winding
      • Connecting Pole-Phase-Groups of a Winding
      • General Theory on Which Connection Diagrams are Constructed
      • Determining Number of Poles from Slot Throw of Coils
      • Typical Circle Diagrams for Connecting Induction Motors
  • Commutator Repairs
    • Causes of Commutator Troubles
    • Troubles Resulting from High Mica
    • Remedy for High and Low Bars
    • Burn-out between Bars
    • Plugging a Commutator
    • Removing Bars and Mica Segments for Repairs
    • Repairing a Burned Commutator Bar
    • Replacing a Repaired Commutator Bar
    • Tightening up a Repaired Commutator
    • Baking Commutator with Electric Heat
    • Removing and Repairing Grounds in a Commutator
    • Turning down a Commutator without Removing Armature
    • Temporary Cover for Use When Turning down a Commutator
    • Refilling a Commutator
    • Boring out the End of a Commutator
    • Mica Used in Commutators
    • Shaping Mica End Rings
    • Templet for Making Mica End Rings
    • Micanite as a Commutator Insulation
    • Precautions when Tightening a Commutator
    • Making Micanite End Rings
    • Causes of Excessive Commutator Wear
    • Copper Used for Making Commutator Bars
    • Test for Oil-Saturated Mica in a Commutator
    • Blackening of a Commutator at Equally Spaced Points
    • Undercutting Mica of Commutators
      • Tools for Undercutting Mica
      • Size of Circular Saw Required
      • Finishing Slots and Commutator Surface after Undercutting
      • Brushes for Use on Undercut Commutators
      • Hand Tools for Undercutting Mica of Commutators
  • Adjusting Brushes and Correcting Brush Troubles
    • Fitting or Grinding-in Brushes
    • Adjustment of Brush Holders
    • Causes of Rapid Brush Wear
    • Methods for Locating the Electrical Neutral in Setting Brushes
    • Angle at Which Brush is Set
    • Checking Brush Setting
    • Brush Pressure
    • Common Brush Terms
    • Procedure for Locating Causes of Brush Troubles
      • Too Low Brush Pressure
      • Incorrect Spacing of Brushes
      • Brushes Not Operating on Electrical Neutral
      • Incorrect Thickness of Brushes
      • Using Brushes of Wrong Characteristics
    • Causes and Remedies for Sparking at Brushes
    • Causes and Remedies for Flat Spots on Commutator
    • Causes and Remedies for Blackening of Commutator
    • Causes of Heating in a Motor or Generator
    • Causes and Remedies for Honey-Combing of Brush Faces
    • Causes and Remedies for Brushes Picking up Copper
    • Causes and Remedies for Brushes Chattering
    • Causes and Remedies for Loosening of Brush Shunts
  • Inspection and Repair of Motor Starters, Motors and Generators
    • Cost of Repairs for Polyphase Motors
    • Points to Consider When Estimating Cost of Motor Repairs
    • Inspection and Overhauling of
      • Direct-Current Motor Starters
      • Auto-Starters for AC Motors
      • Drum Type Controllers
      • Large Compound DC Motor
      • 50-Hp. Induction Motor
      • 25-Hp. Slip-ring Motor
      • Single-Phase Commutator Motor
      • Direct-Current Engine Type Generator
  • Diagnosis of Motor and Generator Troubles
    • Lack of Proper Cleaning
    • Operation in Damp Places
    • Exposure to Acid Fumes and Gases
    • Lack of Frequent Inspection and Replacement of Worn Parts
    • Operating Temperatures too High
    • Electrical Defects
    • Causes and Remedies for Troubles in AC Machines
      • Induction Motor Troubles
      • Locating Troubles in Windings of Induction Motors
      • Mechanical Adjustments
      • Troubles Due to Electrical Faults
      • Troubles with Synchronous Motors
      • Causes of AC Motor Fuses Blowing
      • Inspection of Motor Starting Devices
      • Testing Motor for Grounds
      • Hot Stator Coils
      • Tension of Belt
      • Troubles in Rotor Windings
      • Examination of Stator Winding
      • Sparking at Slip Rings
  • Methods Used by Electrical Repairmen to Solve Special Troubles
    • Sparking at Commutator Caused by Poor Belt Joints
    • Plugging a Commutator
    • Knock in an Armature Due to Band Wires Being too High
    • Heating of Armature Traced to Poor Soldering of Commutator Connections
    • How a Commutator Was Repaired under Difficulties
    • Holder for Sandpapering Commutator
    • Use of Portable Electric Drill to Undercut Mica
    • Jerky Operation of New Commutator Traced to Burred Commutator Bars
    • Why Brush Studs Heated on an 8-Pole Machine
    • An Accident Due to Incorrectly Set Brushes
    • Wrong Setting of Brushes for Direction of Rotation Caused Motor to Flash
    • Proper Adjustment of a Reaction-Type Brush Holder
    • Heating of Brush Holders Traced to Defective Contact Springs
    • Simple Scheme for Banding Armatures
    • Use of a Crane to Band an Armature
    • Method Used to Band a 2000-Hp. Rotor
    • Improvised Method Used to Turn a Commutator
    • Cause of a Motor Reversing its Direction of Rotation on High Speed
    • Checking Connections of an Interpole Motor
    • Heating of Field Coils Traced to Wrong Type of Starting Box
    • Safe Operating Temperature of Portable Desk Fans
    • An Adjustable Shunt for Series Fields of Exciters
    • A Peculiar High-Speed Motor Trouble
    • Ways that End Play Variations Show up
    • Connections for Two 220-Volt Motors When Operated on 440 Volts
    • Cleaning Motors with Compressed Air
    • Testing out Phase Rotation
    • An Induction Motor Trouble Due to Wrong Stator Connections
    • Stalling of Wound Rotor Induction Motor Explained
    • Loose Bearing Caused Induction Motor to Fail to Start
    • Three-Phase Motors Used on Single-Phase Lines
    • An Apparent Overload Trouble That Was Traced to a Defective Fuse Block
    • Cause of Noise in Three-Phase Motor Driving Exhaust Fan
    • Cause of Burned out Starting Winding in a Single-Phase Motor
    • Cause of One Motor Failing to Start While Another Was Running on Same Circuit
    • Cause of Synchronous Motor Failing to Start
    • Effect of Decreased Frequency on Induction Motor-Generator Set
    • Simple Rules for Reconnecting AC Motors
    • Changing 440-Volt Motor for Operation on 220 Volts
    • Multiple Connection Diagram for AC Motor Windings
    • Brush and Slip-Ring Sparking Traced to Absence of Rotor Balancing Weights
    • Overheating of an Induction Motor Traced to Variation in Frequency
    • Relief for a Hot Bearing
    • Static Sparks from Belts
    • Ratings of AC Generators
    • Alternating Current Motor Phase Rotation
    • End Bells or Heads
    • Brushes and Brush Holders
    • The Rotor
    • The Stator
    • Sizes of Fuses for AC Motors
  • Machine Equipment and Tools Needed in a Repair Shop
    • Armature Winder's Tools
    • Device for Shaping Insulating Cells of Armature Slots
    • Tool for Cutting Cell Lining at Top of Slot
    • Special Winding Tools
    • Repair Tools That Can Be Made from Old Hack-Saw Blades
    • Special Coil-Winding Device
    • Steadying Brace for Repairing Small Motors
    • Tension Block for Use When Banding Armatures
    • Armature Sling
    • Pinion Puller
    • Coil Winding Machines
    • Coil-Taping Machines
    • Commutator-Slotting and Grinding Machines
    • Armature Banding Machine
    • Combination Machines
  • Appendix -- Data and Reference Tables
    • How to Remember the Wire Table
    • Copper for Various Systems of Distribution
    • Classification of Wire Gauges
    • General Wiring Formulas for AC and DC Circuits
    • Data for Connecting Motors to Supply Circuits
    • Voltage, Horsepower and Speeds of Motors
    • Transformer Rating for AC Motors
    • Sizes of Fuses Switches and Lead Wires for Motors of Different Sizes on Different Voltages
    • Circuit Breakers for Overload Protection of Motors
    • Belting
    • Rules for Pulley Sizes
    • Speed of Pulleys
    • Chain Drives
    • Points to Consider When Calculating Size of Chain
    • Horsepower Transmitted by Steel Shafting
    • Horsepower Transmitted by Single Ropes
    • Gear Table
    • Some Handy Rules
  • Index
Format:PDF Digital Reprint, e-Facsimile
No. of Pages:531
Page Size:A4 (210mm × 297mm)
Download Size:169 MB
Product CodeARM3ST2A63
ConditionNew
DigitalDownload

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