NEMA-MG-1-2004_-_Motors_and_Generators.pdf

List of Changes for MG 1-2003, Revision 1-2004

The following have been revised:

Contents, pages vii, viii, xii, xv, xxvii Section I, Part 5, pages 1, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16 Section II, Part 12, pages 18, 26, 35, 37, 39, 41, 43 Section II, Part 14, pages 2, 15, 16, 17 Section III, Part 20, page 10 Section III, Part 21, page 27 Section IV, Part 30, pages 1, 5, 7, 8, 9 Index, pages 3, 4, 5

The revisions are indicated with ▲.

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Copyright National Electrical Manufacturers Association Provided by IHS under license with NEMA Licensee=USCG/9961383100

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ANSI Approval Date September 3, 2004

NEMA Standards Publication ANSI/NEMA MG 1-2003, Revision 1-2004

Motors and Generators

Revisions are indicated with ▲.

Published by:

National Electrical Manufacturers Association 1300 North 17th Street, Suite 1847 Rosslyn, VA 22209 www.nema.org

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NOTICE AND DISCLAIMER

The information in this publication was considered technically sound by the consensus of persons engaged in the development and approval of the document at the time it was developed.

Consensus does not necessarily mean that there is unanimous agreement among every person participating in the development of this document.

The National Electrical Manufacturers Association (NEMA) standards and guideline publications, of which the document contained herein is one, are developed through a voluntary consensus standards development process. This process brings together volunteers and/or seeks out the views of persons who have an interest in the topic covered by this publication. While NEMA administers the process and establishes rules to promote fairness in the development of consensus, it does not write the document and it does not independently test, evaluate, or verify the accuracy or completeness of any information or the soundness of any judgments contained in its standards and guideline publications.

NEMA disclaims liability for any personal injury, property, or other damages of any nature whatsoever, whether special, indirect, consequential, or compensatory, directly or indirectly resulting from the publication, use of, application, or reliance on this document. NEMA disclaims and makes no guaranty or warranty, expressed or implied, as to the accuracy or completeness of any information published herein, and disclaims and makes no warranty that the information in this document will fulfill any of your particular purposes or needs. NEMA does not undertake to guarantee the performance of any individual manufacturer or seller’s products or services by virtue of this standard or guide.

In publishing and making this document available, NEMA is not undertaking to render professional or other services for or on behalf of any person or entity, nor is NEMA undertaking to perform any duty owed by any person or entity to someone else. Anyone using this document should rely on his or her own independent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances. Information and other standards on the topic covered by this publication may be available from other sources, which the user may wish to consult for additional views or information not covered by this publication.

NEMA has no power, nor does it undertake to police or enforce compliance with the contents of this document. NEMA does not certify, test, or inspect products, designs, or installations for safety or health purposes. Any certification or other statement of compliance with any health or safety–related information in this document shall not be attributable to NEMA and is solely the responsibility of the certifier or maker of the statement.

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MG 1-2003

Page i

© Copyright by the National Electrical Manufacturers Association.

CONTENTS

Page No.

Foreword..........................................................................................................................................xxxv

Section I GENERAL STANDARDS APPLYING TO ALL MACHINES Part 1—REFERENCED STANDARDS AND DEFINITIONS ............................................................1-1 REFERENCED STANDARDS ..........................................................................................................1-1 DEFINITIONS ....................................................................................................................................1-4 CLASSIFICATION ACCORDING TO SIZE ......................................................................................1-4

1.2 MACHINE .............................................................................................................................1-4

1.3 SMALL (FRACTIONAL) MACHINE ......................................................................................1-4

1.4 MEDIUM (INTEGRAL) MACHINE ........................................................................................1-4

1.4.1 Alternating-Current Medium Machine.........................................................................1-4

1.4.2 Direct-Current Medium Machine.................................................................................1-4

1.5 LARGE MACHINE ................................................................................................................1-4

1.5.1 Alternating-Current Large Machine.............................................................................1-4

1.5.2 Direct-Current Large Machine ....................................................................................1-5 CLASSIFICATION ACCORDING TO APPLICATION ......................................................................1-5

1.6 GENERAL PURPOSE MOTOR............................................................................................1-5

1.6.1 General-Purpose Alternating-Current Motor...............................................................1-5

1.6.2 General-Purpose Direct-Current Small Motor ............................................................1-5

1.7 GENERAL-PURPOSE GENERATOR..................................................................................1-5

1.8 INDUSTRIAL SMALL MOTOR .............................................................................................1-5

1.9 INDUSTRIAL DIRECT-CURRENT MEDIUM MOTOR.........................................................1-5

1.10 INDUSTRIAL DIRECT-CURRENT GENERATOR ...............................................................1-5

1.11 DEFINITE-PURPOSE MOTOR ............................................................................................1-6

1.12 GENERAL INDUSTRIAL MOTOR........................................................................................1-6

1.13 METAL ROLLING MILL MOTORS .......................................................................................1-6

1.14 REVERSING HOT MILL MOTORS ......................................................................................1-6

1.15 SPECIAL-PURPOSE MOTOR .............................................................................................1-6

1.16 NEMA PREMIUM™ EFFICIENCY MOTOR.........................................................................1-6 CLASSIFICATION ACCORDING TO ELECTRICAL TYPE .............................................................1-6

1.17 GENERAL.............................................................................................................................1-6

1.17.1 Electric Motor .............................................................................................................1-6

1.17.2 Electric Generator......................................................................................................1-6

1.17.3 Electric Machines.......................................................................................................1-6

1.18 ALTERNATING-CURRENT MOTORS.................................................................................1-7

1.18.1 Induction Motor ..........................................................................................................1-7

1.18.2 Synchronous Motor....................................................................................................1-7

1.18.3 Series-Wound Motor.................................................................................................1-7

1.19 POLYPHASE MOTORS .......................................................................................................1-8

1.19.1 Design Letters of Polyphase Squirrel-Cage Medium Motors ....................................1-8

1.20 SINGLE-PHASE MOTORS ..................................................................................................1-8

1.20.1 Design Letters of Single-Phase Small Motors ...........................................................1-8

1.20.2 Design Letters of Single-Phase Medium Motors .......................................................1-9

1.20.3 Single-Phase Squirrel-cage Motors...........................................................................1-9

1.20.4 Single-Phase Wound-Rotor Motors.........................................................................1-10

1.21 UNIVERSAL MOTORS.......................................................................................................1-10

1.21.1 Series-Wound Motor................................................................................................1-10

1.21.2 Compensated Series-Wound Motor ........................................................................1-10

1.22 ALTERNATING-CURRENT GENERATORS......................................................................1-10

1.22.1 Induction Generator .................................................................................................1-10

1.22.2 Synchronous Generator...........................................................................................1-10

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Page ii

1.23 DIRECT-CURRENT MOTORS...........................................................................................1-10

1.23.1 Shunt-Wound Motor.................................................................................................1-11

1.23.2 Series-Wound Motor................................................................................................1-11

1.23.3 Compound-Wound Motor ........................................................................................1-11

1.23.4 Permanent Magnet Motor ........................................................................................1-11

1.24 DIRECT-CURRENT GENERATORS .................................................................................1-11

1.24.1 Shunt-Wound Generator..........................................................................................1-11

1.24.2 Compound-Wound Generator .................................................................................1-11

CLASSIFICATION ACCORDING TO ENVIRONMENTAL PROTECTION AND METHODS

OF COOLING ..................................................................................................................................1-11

1.25 OPEN MACHINE (IP00, IP01)............................................................................................1-11

1.25.1 Dripproof Machine (IP12, IP01) ...............................................................................1-12

1.25.2 Splash-Proof Machine (IP13, IP01) .........................................................................1-12

1.25.3 Semi-Guarded Machine (IC01)................................................................................1-12

1.25.4 Guarded Machine (IC01) .........................................................................................1-12

1.25.5 Dripproof Guarded Machine (IC01) .........................................................................1-15

1.25.6 Open Independently Ventilated Machine (IC06)......................................................1-15

1.25.7 Open Pipe-Ventilated Machine................................................................................1-15

1.25.8 Weather-Protected Machine ....................................................................................1-15

1.26 TOTALLY ENCLOSED MACHINE .....................................................................................1-15

1.26.1 Totally Enclosed Nonventilated Machine (IC410)....................................................1-15

1.26.2 Totally Enclosed Fan-Cooled Machine....................................................................1-15

1.26.3 Totally Enclosed Fan-Cooled Guarded Machine (IP54, IC411) ..............................1-16

1.26.4 Totally Enclosed Pipe-Ventilated Machine (IP44) ...................................................1-16

1.26.5 Totally Enclosed-Water-Cooled Machine (IP54) .....................................................1-16

1.26.6 Water-Proof Machine (IP55) ....................................................................................1-16

1.26.7 Totally Enclosed Air-to-Water-Cooled Machine (IP54)............................................1-16

1.26.8 Totally Enclosed Air-to-Air Cooled Machine (IP54) .................................................1-16

1.26.9 Totally Enclosed Air-Over Machine (IP54, IC417)...................................................1-16

1.26.10 Explosion-Proof Machine.......................................................................................1-17

1.26.11 Dust-Ignition-Proof Machine ..................................................................................1-17

1.27 MACHINE WITH ENCAPSULATED OR SEALED WINDINGS..........................................1-17

1.27.1 Machine with Moisture Resistant Windings .............................................................1-17

1.27.2 Machine with Sealed Windings................................................................................1-17 CLASSIFICATION ACCORDING TO VARIABILITY OF SPEED ..................................................1-17

1.30 CONSTANT-SPEED MOTOR ............................................................................................1-17

1.31 VARYING-SPEED MOTOR................................................................................................1-17

1.32 ADJUSTABLE-SPEED MOTOR.........................................................................................1-18

1.33 BASE SPEED OF AN ADJUSTABLE-SPEED MOTOR.....................................................1-18

1.34 ADJUSTABLE VARYING-SPEED MOTOR........................................................................1-18

1.35 MULTISPEED MOTOR.......................................................................................................1-18 RATING, PERFORMANCE, AND TEST.........................................................................................1-18

1.40 RATING OF A MACHINE ...................................................................................................1-18

1.40.1 Continuous Rating ...................................................................................................1-18

1.40.2 Short-Time Rating....................................................................................................1-18

1.41 EFFICIENCY.......................................................................................................................1-18

1.41.1 General ....................................................................................................................1-18

1.41.2 Energy Efficient Polyphase Squirrel-Cage Induction Motor ....................................1-18

1.42 SERVICE FACTOR—AC MOTORS...................................................................................1-19

1.43 SPEED REGULATION OF DC MOTORS ..........................................................................1-19

1.43.1 Percent Compounding of Direct-Current Machines.................................................1-19

1.44 VOLTAGE REGULATION OF DIRECT-CURRENT GENERATORS.................................1-19

1.45 SECONDARY VOLTAGE OF WOUND-MOTOR ROTORS...............................................1-19

1.46 FULL-LOAD TORQUE........................................................................................................1-19

1.47 LOCKED-ROTOR TORQUE (STATIC TORQUE)..............................................................1-19

1.48 PULL-UP TORQUE ............................................................................................................1-19

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Page iii

1.49 PUSHOVER TORQUE .......................................................................................................1-19

1.50 BREAKDOWN TORQUE....................................................................................................1-19

1.51 PULL-OUT TORQUE..........................................................................................................1-20

1.52 PULL-IN TORQUE..............................................................................................................1-20

1.53 LOCKED-ROTOR CURRENT ............................................................................................1-20

1.54 NO-LOAD CURRENT ........................................................................................................1-20

1.55 TEMPERATURE TESTS ....................................................................................................1-20

1.56 AMBIENT TEMPERATURE................................................................................................1-20

1.57 HIGH-POTENTIAL TESTS .................................................................................................1-20

1.58 STARTING CAPACITANCE FOR A CAPACITOR MOTOR ..............................................1-20

1.59 RADIAL MAGNETIC PULL AND AXIAL CENTERING FORCE.........................................1-20

1.59.1 Radial Magnetic Pull ................................................................................................1-20

1.59.2 Axial Centering Force ..............................................................................................1-20

1.60 INDUCTION MOTOR TIME CONSTANTS.........................................................................1-21

1.60.1 General ....................................................................................................................1-21

1.60.2 Open-Circuit AC Time Constant ..............................................................................1-21

1.60.3 Short-Circuit AC Time Constant ..............................................................................1-21

1.60.4 Short-Circuit DC Time Constant ..............................................................................1-21

1.60.5 X/R Ratio..................................................................................................................1-21

1.60.6 Definitions (See Figure 1-4).....................................................................................1-21 COMPLETE MACHINES AND PARTS...........................................................................................1-22

1.61 SYNCHRONOUS GENERATOR—COMPLETE ................................................................1-22

1.61.1 Belted Type..............................................................................................................1-22

1.61.2 Engine Type.............................................................................................................1-22

1.61.3 Coupled Type...........................................................................................................1-22

1.62 DIRECT-CURRENT GENERATOR—COMPLETE ............................................................1-22

1.62.1 Belted Type..............................................................................................................1-22

1.62.2 Engine Type.............................................................................................................1-22

1.62.3 Coupled Type...........................................................................................................1-22

1.63 FACE AND FLANGE MOUNTING......................................................................................1-22

1.63.1 Type C Face ............................................................................................................1-22

1.63.2 Type D Flange .........................................................................................................1-23

1.63.3 Type P Flange..........................................................................................................1-23 CLASSIFICATION OF INSULATION SYSTEMS ...........................................................................1-23

1.65 INSULATION SYSTEM DEFINED......................................................................................1-23

1.65.1 Coil Insulation with its Accessories..........................................................................1-23

1.65.2 Connection and Winding Support Insulation ...........................................................1-23

1.65.3 Associated Structural Parts .....................................................................................1-23

1.66 CLASSIFICATION OF INSULATION SYSTEMS ...............................................................1-23 MISCELLANEOUS..........................................................................................................................1-24

1.70 NAMEPLATE MARKING ....................................................................................................1-24

1.71 CODE LETTER...................................................................................................................1-24

1.72 THERMAL PROTECTOR ...................................................................................................1-24

1.73 THERMALLY PROTECTED ...............................................................................................1-24

1.74 OVER TEMPERATURE PROTECTION.............................................................................1-25

1.75 PART-WINDING START MOTOR......................................................................................1-25

1.76 STAR (WYE) START, DELTA RUN MOTOR.....................................................................1-25

1.77 CONSTANT FLUX..............................................................................................................1-25

1.78 MARKING ABBREVIATIONS FOR MACHINES ................................................................1-25

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Page iv

Section I GENERAL STANDARDS APPLYING TO ALL MACHINES Part 2—TERMINAL MARKINGS GENERAL .........................................................................................................................................2-1

2.1 LOCATION OF TERMINAL MARKINGS..............................................................................2-1

2.2 TERMINAL MARKINGS........................................................................................................2-1

2.3 DIRECTION OF ROTATION ................................................................................................2-2

2.3.1 Alternating-Current Machines .....................................................................................2-2

2.3.2 Direct-Current Machines.............................................................................................2-2

2.3.3 Motor-Generator Sets .................................................................................................2-2 DC MOTORS AND GENERATORS..................................................................................................2-2

2.10 TERMINAL MARKINGS........................................................................................................2-2

2.10.1 General ......................................................................................................................2-2

2.10.2 Armature Leads .........................................................................................................2-2

2.10.3 Armature Leads—Direction of Rotation.....................................................................2-2

2.11 TERMINAL MARKINGS FOR DUAL VOLTAGE SHUNT FIELDS.......................................2-2

2.12 DIRECTION OF ROTATION ................................................................................................2-3

2.12.1 Direct-Current Motors ................................................................................................2-3

2.12.2 Direct-Current Generators .........................................................................................2-3

2.12.3 Reverse Function.......................................................................................................2-3

2.13 CONNECTION DIAGRAMS WITH TERMINAL MARKINGS FOR

DIRECT-CURRENT MOTORS.............................................................................................2-3

2.14 CONNECTION DIAGRAMS WITH TERMINAL MARKINGS FOR

DIRECT-CURRENT GENERATORS ...................................................................................2-7 AC MOTORS AND GENERATORS..................................................................................................2-9

2.20 NUMERALS ON TERMINALS OF ALTERNATING-CURRENT

POLYPHASE MACHINES ....................................................................................................2-9

2.20.1 Synchronous Machines .............................................................................................2-9

2.20.2 Induction Machines....................................................................................................2-9

2.21 DEFINITION OF PHASE SEQUENCE.................................................................................2-9

2.22 PHASE SEQUENCE.............................................................................................................2-9

2.23 DIRECTION OF ROTATION OF PHASORS........................................................................2-9

2.24 DIRECTION OF ROTATION ..............................................................................................2-10 AC GENERATORS AND SYNCHRONOUS MOTORS ..................................................................2-10

2.25 REVERSAL OF ROTATION, POLARITY AND PHASE SEQUENCE................................2-10

2.30 CONNECTION AND TERMINAL MARKINGS—ALTERNATING-

CURRENT GENERATORS AND SYNCHRONOUS MOTORS—

THREE-PHASE AND SINGLE-PHASE..............................................................................2-10 SINGLE PHASE MOTORS .............................................................................................................2-11

2.40 GENERAL...........................................................................................................................2-11

2.40.1 Dual Voltage ............................................................................................................2-11

2.40.2 Single Voltage..........................................................................................................2-11

2.41 TERMINAL MARKINGS IDENTIFIED BY COLOR.............................................................2-12

2.42 AUXILIARY DEVICES WITHIN MOTOR............................................................................2-12

2.43 AUXILIARY DEVICES EXTERNAL TO MOTOR................................................................2-12

2.44 MARKING OF RIGIDLY MOUNTED TERMINALS.............................................................2-12

2.45 INTERNAL AUXILIARY DEVICES PERMANENTLY CONNECTED

TO RIGIDLY MOUNTED TERMINALS...............................................................................2-13

2.46 GENERAL PRINCIPLES FOR TERMINAL MARKINGS FOR

SINGLE-PHASE MOTORS ................................................................................................2-13

2.46.1 First Principle ...........................................................................................................2-13

2.46.2 Second Principle......................................................................................................2-13

2.46.3 Third Principle..........................................................................................................2-13

2.47 SCHEMATIC DIAGRAMS FOR SPLIT-PHASE MOTORS—

SINGLE VOLTAGE—REVERSIBLE ..................................................................................2-14

2.47.1 Without Thermal Protector.......................................................................................2-14

2.47.2 With Thermal Protector............................................................................................2-14

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Page v

2.48 SCHEMATIC DIAGRAMS FOR CAPACITOR-START MOTORS—

REVERSIBLE .....................................................................................................................2-15

2.48.1 Single-Voltage Capacitor-start Motors—Reversible ................................................2-15

2.48.2 Dual-Voltage Capacitor-start Motors—Reversible...................................................2-16

2.49 SCHEMATIC DIAGRAMS FOR TWO-VALUE CAPACITOR

MOTORS—SINGLE VOLTAGE—REVERSIBLE...............................................................2-20

2.49.1 Without Thermal Protector.......................................................................................2-20

2.49.2 With Thermal Protector............................................................................................2-21

2.50 SCHEMATIC DIAGRAMS FOR PERMANENT-SPLIT CAPACITOR

MOTORS—SINGLE VOLTAGE—REVERSIBLE...............................................................2-22

2.51 SCHEMATIC DIAGRAMS FOR UNIVERSAL MOTORS—

SINGLE VOLTAGE.............................................................................................................2-23

2.52 SCHEMATIC DIAGRAMS FOR REPULSION, REPULSION-START

INDUCTION, AND REPULSION-INDUCTION MOTORS ..................................................2-24

2.53 SHADED-POLE MOTORS—TWO SPEED........................................................................2-25

2.60 GENERAL PRINCIPLES FOR TERMINAL MARKINGS FOR

POLYPHASE INDUCTION MOTORS ................................................................................2-25

2.60.1 General ....................................................................................................................2-25

2.60.2 Three-Phase, Two Speed Motors............................................................................2-26

2.60.3 Two-Phase Motors...................................................................................................2-26

2.61 TERMINAL MARKINGS FOR THREE-PHASE SINGLE-SPEED

INDUCTION MOTORS .......................................................................................................2-26

2.61.1 First ..........................................................................................................................2-26

2.61.2 Second.....................................................................................................................2-26

2.61.3 Third.........................................................................................................................2-26

2.61.4 Fourth.......................................................................................................................2-26

2.61.5 Fifth ..........................................................................................................................2-26

2.61.6 Sixth .........................................................................................................................2-26

2.62 TERMINAL MARKINGS FOR Y- AND DELTA-CONNECTED

DUAL VOLTAGE MOTORS ...............................................................................................2-27

2.63 TERMINAL MARKINGS FOR THREE-PHASE TWO-SPEED

SINGLE-WINDING INDUCTION MOTORS........................................................................2-27

2.64 TERMINAL MARKINGS FOR Y- AND DELTA-CONNECTED

THREE-PHASE TWO-SPEED SINGLE-WINDING MOTORS...........................................2-27

2.65 TERMINAL MARKINGS FOR THREE-PHASE INDUCTION

MOTORS HAVING TWO OR MORE SYNCHRONOUS SPEEDS

OBTAINED FROM TWO OR MORE INDEPENDENT WINDINGS....................................2-33

2.65.1 Each Independent Winding Giving One Speed .......................................................2-33

2.65.2 Each Independent Winding Reconnectible to Give Two

Synchronous Speeds...............................................................................................2-33

2.65.3 Two or More Independent Windings at Least One of Which Gives One Synchronous Speed and the Other Winding Gives Two Synchronous Speeds.............................................................................2-34

2.66 TERMINAL MARKINGS OF THE ROTORS OF WOUND-ROTOR

INDUCTION MOTORS .......................................................................................................2-35

Section I GENERAL STANDARDS APPLYING TO ALL MACHINES Part 3—HIGH-POTENTIAL TESTS

3.1 HIGH-POTENTIAL TESTS ...................................................................................................3-1

3.1.1 Safety..........................................................................................................................3-1

3.1.2 Definition .....................................................................................................................3-1

3.1.3 Procedure ...................................................................................................................3-1

3.1.4 Test Voltage................................................................................................................3-1

3.1.5 Condition of Machine to be Tested.............................................................................3-1

3.1.6 Duration of Application of Test Voltage ......................................................................3-1

3.1.7 Points of Application of Test Voltage..........................................................................3-2

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Page vi

3.1.8 Accessories and Components ....................................................................................3-2

3.1.9 Evaluation of Dielectric Failure ...................................................................................3-2

3.1.10 Initial Test at Destination ...........................................................................................3-2

3.1.11 Tests of an Assembled Group of Machines and Apparatus ......................................3-2

3.1.12 Additional Tests Made After Installation ....................................................................3-3

Section I GENERAL STANDARDS APPLYING TO ALL MACHINES Part 4—DIMENSIONS, TOLERANCES, AND MOUNTING

4.1 LETTERING OF DIMENSION SHEETS...............................................................................4-1

4.2 SYSTEM FOR DESIGNATING FRAMES...........................................................................4-10

4.2.1 Frame Numbers........................................................................................................4-10

4.2.2 Frame Letters............................................................................................................4-11

4.3 MOTOR MOUNTING AND TERMINAL HOUSING LOCATION.........................................4-12 Figure 4-6............................................................................................................................4-13

4.4 DIMENSIONS—AC MACHINES ........................................................................................4-14

4.4.1 Dimensions for Alternating-Current Foot-Mounted

Machines with Single Straight-Shaft Extension ........................................................4-14

4.4.2 Shaft Extensions and Key Dimensions for Alternating-

Current Foot-Mounted Machines with Single Tapered or Double Straight/Tapered Shaft Extension ................................................................4-16

4.4.3 Shaft Extension Diameters and Key Dimensions for

Alternating-Current Motors Built in Frames Larger than the 449T Frames ..............4-17

4.4.4 Dimensions for Type C Face-Mounting Foot or Footless

Alternating-Current Motors........................................................................................4-17

4.4.5 Dimensions for Type FC Face Mounting for Accessories

on End of Alternating-Current Motors .......................................................................4-18

4.4.6 Dimensions for Type D Flange-Mounting Foot or Footless

Alternating-Current Motors........................................................................................4-19

4.5 DIMENSIONS—DC MACHINES ........................................................................................4-20

4.5.1 Dimensions for Direct-Current Small Motors with

Single Straight Shaft Extension ................................................................................4-20

4.5.2 Dimensions for Foot-Mounted Industrial Direct-Current Machines ..........................4-21

4.5.3 Dimensions for Foot-Mounted Industrial Direct-Current Motors...............................4-25

4.5.4 Dimensions for Type C Face-Mounting Direct-Current

Small Motors .............................................................................................................4-26

4.5.5 Dimensions for Type C Face-Mounting Industrial Direct-Current Motors................4-26

4.5.6 Dimensions for Type C Face-Mounting Industrial Direct-Current Motors.................4-27

4.5.7 Dimensions for Type D Flange-Mounting Industrial Direct-Current Motors .............4-27

4.5.8 Base Dimensions for Type P and PH Vertical Solid-Shaft

Industrial Direct-Current Motors................................................................................4-28

4.5.9 Dimensions for Type FC Face Mounting for Accessories

on End Opposite Drive End of Industrial Direct-Current Motors...............................4-28

4.6 SHAFT EXTENSION DIAMETERS FOR UNIVERSAL MOTORS .....................................4-28

4.7 TOLERANCE LIMITS IN DIMENSIONS.............................................................................4-29

4.8 KNOCKOUT AND CLEARANCE HOLE DIAMETER FOR MACHINE

TERMINAL BOXES ............................................................................................................4-29

4.9 TOLERANCES ON SHAFT EXTENSION DIAMETERS AND

KEYSEATS .........................................................................................................................4-29

4.9.1 Shaft Extension Diameter .........................................................................................4-29

4.9.2 Keyseat Width...........................................................................................................4-29

4.9.3 Bottom of Keyseat to Shaft Surface..........................................................................4-29

4.9.4 Parallelism ................................................................................................................4-30

4.9.5 Lateral Displacement ................................................................................................4-30

4.9.6 Diameters and Keyseat Dimensions ........................................................................4-30

4.9.7 Shaft Runout .............................................................................................................4-30

4.10 RING GROOVE SHAFT KEYSEATS FOR VERTICAL SHAFT MOTORS........................4-32

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MG 1-2003, Rev 1-2004 Page vii

4.11 METHOD OF MEASUREMENT OF SHAFT RUNOUT AND OF

ELECTRICITY AND FACE RUNOUT OF MOUNTING SURFACES .................................4-32

4.11.1 Shaft Runout ............................................................................................................4-32

4.11.2 Eccentricity and Face Runout of Mounting Surfaces...............................................4-32

4.12 TOLERANCES FOR TYPE C FACE MOUNTING AND TYPE D

FLANGE MOUNTING MOTORS........................................................................................4-32

4.13 TOLERANCES FOR TYPE P FLANGE-MOUNTING MOTORS........................................4-33

4.14 MOUNTING BOLTS OR STUDS........................................................................................4-33

4.15 METHOD TO CHECK COPLANARITY OF FEET OF FULLY

ASSEMBLED MOTORS .....................................................................................................4-34

4.16 METHOD OF MEASUREMENT OF SHAFT EXTENSION

PARALLELISM TO FOOT PLANE .....................................................................................4-34

4.17 MEASUREMENT OF BEARING TEMPERATURE ............................................................4-34

4.18 TERMINAL CONNECTIONS FOR SMALL MOTORS........................................................4-35

4.18.1 Terminal Leads ........................................................................................................4-35

4.18.2 Blade Terminals.......................................................................................................4-35

4.19 MOTOR TERMINAL HOUSINGS.......................................................................................4-35

4.19.1 Small and Medium Motors .......................................................................................4-35

4.19.2 Dimensions ..............................................................................................................4-35

4.19.2.1 Terminal Housings for Wire-to-wire Connections—

Small and Medium Machines...................................................................4-35

4.20 GROUNDING MEANS FOR FIELD WIRING .....................................................................4-41

Section I GENERAL STANDARDS APPLYING TO ALL MACHINES Part 5—ROTATING ELECTRICAL MACHINES—CLASSIFICATION OF

DEGREES OF PROTECTION PROVIDED BY ENCLOSURES FOR

ROTATING MACHINES ▲

5.1 SCOPE .................................................................................................................................5-1

5.2 DESIGNATION ▲................................................................................................................5-1

5.2.1 Single Characteristic Numeral ....................................................................................5-1

5.2.2 Supplementary Letters................................................................................................5-1

5.2.3 Example of Designation..............................................................................................5-2

5.2.4 Most Frequently Used.................................................................................................5-2

5.3 DEGREES OF PROTECTION—FIRST CHARACTERISTIC NUMERAL ............................5-2

5.3.1 Indication of Degree of Protection ..............................................................................5-2

5.3.2 Compliance to Indicated Degree of Protection ...........................................................5-2

5.3.3 External Fans..............................................................................................................5-2

5.3.4 Drain Holes .................................................................................................................5-3 Table 5-1 ▲ .........................................................................................................................5-3

5.4 DEGREES OF PROTECTION—SECOND CHARACTERISTIC NUMERAL.......................5-4

5.4.1 Indication of Degree of Protection ▲.........................................................................5-4

5.4.2 Compliance to Indicated Degree of Protection ...........................................................5-4 Table 5-2 ▲ .........................................................................................................................5-4

5.5 MARKING .............................................................................................................................5-5

5.6 GENERAL REQUIREMENTS FOR TESTS ▲....................................................................5-5

5.6.1 Adequate Clearance ...................................................................................................5-5

5.7 TESTS FOR FIRST CHARACTERISTIC NUMERAL ▲ .....................................................5-5 Table 5-3 ▲ .........................................................................................................................5-6

5.8 TESTS FOR SECOND CHARACTERISTIC NUMERAL......................................................5-7

5.8.1 Test Conditions ▲ .....................................................................................................5-7 Table 5-4...............................................................................................................................5-8

5.8.2 Acceptance Conditions ▲ .......................................................................................5-10

5.8.3 Allowable Water Leakage .........................................................................................5-10

5.9 REQUIREMENTS AND TESTS FOR OPEN WEATHER-PROTECTED MACHINES.......5-10

Figure 5-1 ▲ ......................................................................................................................5-11

Copyright National Electrical Manufacturers Association Provided by IHS under license with NEMA Licensee=USCG/9961383100

Not for Resale, 01/18/2006 06:28:59 MSTNo reproduction or networking permitted without license from IHS

Page viii

Figure 5-2 ▲ ......................................................................................................................5-12 Figure 5-3 ▲ ......................................................................................................................5-13 Figure 5-4 ▲ ......................................................................................................................5-14 Figure 5-5 ▲ ......................................................................................................................5-15 Figure 5-6 ▲ ......................................................................................................................5-16

Section I GENERAL STANDARDS APPLICABLE TO ALL MACHINES Part 6—ROTATING ELECTRICAL MOTORS—METHODS OF COOLING (IC CODE)

6.1 SCOPE .................................................................................................................................6-1

6.2 DEFINITIONS .......................................................................................................................6-1

6.2.1 Cooling........................................................................................................................6-1

6.2.2 Coolant........................................................................................................................6-1

6.2.3 Primary Coolant ..........................................................................................................6-1

6.2.4 Secondary Coolant .....................................................................................................6-1

6.2.5 Final Coolant...............................................................................................................6-1

6.2.6 Surrounding Medium ..................................................................................................6-1

6.2.7 Remote Medium..........................................................................................................6-2

6.2.8 Direct Cooled Winding (Inner cooled Winding)...........................................................6-2

6.2.9 Indirect Cooled Winding..............................................................................................6-2

6.2.10 Heat Exchange ..........................................................................................................6-2

6.2.11 Pipe, Duct .............................................................