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NEMA MG 1-2011 Information Manual

General purpose industrial ac small and medium squirrel-cage induction motor standards
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NEMA Condensed MG 1-2011
Information Guide for General Purpose Industrial AC Small
and
Medium Squirrel-Cage Induction Motor Standards
Published by
National Electrical Manufacturers Association
1300 North 17th Street, Suite 900
Rosslyn, Virginia 22209
www.nema.org
© 2014 National Electrical Manufacturers Association. All rights, including translation into other languages,
reserved under the Universal Copyright Convention, the Berne Convention for the Protection of Literary
and Artistic Works, and the International and Pan American copyright conventions.

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Summary of Contents for NEMA MG 1-2011

  • Page 1 NEMA Condensed MG 1-2011 Information Guide for General Purpose Industrial AC Small Medium Squirrel-Cage Induction Motor Standards Published by National Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209 www.nema.org © 2014 National Electrical Manufacturers Association. All rights, including translation into other languages, reserved under the Universal Copyright Convention, the Berne Convention for the Protection of Literary and Artistic Works, and the International and Pan American copyright conventions.
  • Page 2 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 circumstance.

  • Page 3: Table Of Contents

    Condensed MG 1-2011 Page i CONTENTS Page Foreword..............................iv PURPOSE ............................2 SCOPE ............................. 2 DEFINITIONS ........................... 2 CLASSIFICATION OF DEGREES OF PROTECTION PROVIDED FOR ENCLOSURES FOR ROTATING MOTORS ........................4 Single Characteristic Numeral ..................... 4 Supplementary Letters ......................4 Letters Following Numerals ....................
  • Page 4 Condensed MG 1-2011 Page ii Grounding Means for Field Wiring ..................10 TESTS AND PERFORMANCE—AC SMALL AND MEDIUM MOTORS ........10 Routine Tests for Polyphase Medium Induction Motors ............ 10 High-Potential Test Voltages for Induction Motors [MG 1-12.3] ........10 Test Methods ........................
  • Page 5 Condensed MG 1-2011 Page iii 9.18 Number of Starts ....................... 15 9.19 Thermal Protection of Medium Motors ................16 9.19.1 Winding Temperature ................... 16 Overtemperature Protection of Medium Motors Not Meeting the Definition of “Thermally 9.20 Protected” .......................... 16 9.20.1 Type 1—Winding Running and Locked Rotor Overtemperature Protection ..16 9.20.2 Type 2—Winding Running Overtemperature Protection ........

  • Page 7: Foreword

    In the preparation of this publication, input of users and other interested parties has been sought and evaluated. Inquiries, comments, and proposed or recommended revisions should be submitted to the concerned NEMA product Subdivision by contacting the: Senior Technical Director, Operations...

  • Page 8: Purpose

    Page 2 PURPOSE This is a condensation of the standards on motors included in NEMA Motors and Generators, MG 1-2011. Some standards are reprinted in their entirety while others have been combined or abbreviated. The numbers placed at the end of many of the paragraphs in this condensation (e.g. MG 1 Part 6) refer to the complete standard in MG 1.
  • Page 9 Condensed MG 1-2011 Page 3 (2) a probe such as that illustrated in Figure 1, when inserted through the openings, will not touch film coated wire. [MG 1-1.25.4] high-potential tests: High-potential tests are tests which consist of the application of a voltage higher than the rated voltage for a specified time for the purpose of determining the adequacy against breakdown of insulating materials and spacings under normal conditions.

  • Page 10: Classification Of Degrees Of Protection Provided For Enclosures For Rotating Motors

    Condensed MG 1-2011 Page 4 voltage unbalance: The voltage unbalance in percent may be defined as follows: percent voltage unbalance = 100 x maximum voltage deviation from average voltage  average voltage Example—With voltages of 460, 467, and 450, the average is 459, the maximum deviation from average is 9, and the percent unbalance = 100 x 9/459 = 1.96 percent.

  • Page 11: Degrees Of Protection-Second Characteristic Numeral

    Condensed MG 1-2011 Page 5 Degrees of Protection—Second Characteristic Numeral The second characteristic numeral indicates the degree of protection provided by the enclosure with respect to harmful effect due to ingress of water. Table 3 gives brief details of the type of protection provided by the enclosure for each of the degrees of protection represented by the second characteristic numeral.

  • Page 12: Frequencies

    Condensed MG 1-2011 Page 6 Frequencies The frequency shall be 50 and 60 hertz. [MG 1-10.31] Horsepower and Speed Ratings 7.3.1 Small Induction Motors The horsepower and speed ratings for small induction motors are shown in Table 6. [MG 1-10.32.1] 7.3.2...

  • Page 13: Code Letters (For Locked-Rotor Kva)-Nameplate Marking

    Condensed MG 1-2011 Page 7 Code Letters (for Locked-Rotor kVA)—Nameplate Marking The nameplate of an alternating-current motor rated 1/2 horsepower and larger may be marked with the caption “Code” followed by a letter selected from the table below to show the locked-rotor kVA per horsepower.

  • Page 14: Nameplate Marking For Medium Single-Phase And Polyphase Induction Motors

    Voltage Code letter for locked-rotor kVA or locked-rotor amperes for motors 1/2 horsepower or larger Design letter for medium motors m) NEMA nominal efficiency, when required Service factor, if other than 1.0 Service factor amps when service factor exceeds 1.15 For motors equipped with thermal protectors, the words “thermally protected”...

  • Page 15: Dimensions-Ac Small (Fractional) And Medium (Integral) Motors

    Condensed MG 1-2011 Page 9 DIMENSIONS—AC SMALL (FRACTIONAL) AND MEDIUM (INTEGRAL) MOTORS System for Designating Frames The system for designating frames of motors consist of a series of numbers in combination with letters, defined as follows: [MG 1-4.2] 8.1.1 Small Motors The frame number for small motors is the D dimension in inches multiplied by 16.

  • Page 16: Frame Assignments

    Condensed MG 1-2011 Page 10 Frame Assignments Frame assignments for alternating current single-phase, Design L, horizontal and vertical, open type motors are given in Table 14. Frame assignments for alternating current, polyphase, squirrel-cage, Designs A, B, and C, horizontal and vertical motors, open type and totally enclosed fan-cooled type are given in Table 15, Table 16, Table 17, and Table 18.

  • Page 17: Test Methods

    Condensed MG 1-2011 Page 11 Test Methods Tests to determine performance characteristics shall be made in accordance with the following: [MG 1-12.30] For single-phase motors—IEEE Std 114 For polyphase induction motors—IEEE Std 112 Performance Characteristics When performance characteristics are provided, they should be expressed as follows: [MG 1-12.31] Current in amperes or percent of rated current.

  • Page 18: Locked-Rotor Current Of 3-Phase 60-Hertz Small And Medium Squirrel-Cage Induction Motors Rated At 230 Volts

    Condensed MG 1-2011 Page 12 9.6.3 Locked-Rotor Current of 3-Phase 60-Hertz Small and Medium Squirrel-Cage Induction Motors Rated at 230 Volts The locked-rotor current of single-speed, 3-phase, constant-speed induction motors rated 230 volts, when measured with rated voltage and frequency impressed and with rotor locked, shall not exceed the values listed in Table 31.

  • Page 19: Variations From Rated Voltage And Rated Frequency

    Condensed MG 1-2011 Page 13 Variations from Rated Voltage and Rated Frequency 9.9.1 Running Alternating-current motors shall operate successfully under running conditions at rated load with a variation in the voltage or the frequency up to the following: Plus or minus 10 percent of rated voltage, with rated frequency for induction motors.

  • Page 20: Stall Time

    Condensed MG 1-2011 Page 14 Repeated overloads resulting in prolonged operation at winding temperatures above the maximum values given in 9.8 will result in reduced insulation life. [MG 1-12.48] 9.14 Stall Time Polyphase motors having outputs not exceeding 500 horsepower and rated voltage not exceeding 1kV shall be capable of withstanding locked-rotor current for not less than 12 seconds when the motor is initially at normal operating temperatures.

  • Page 21: Machine Sound (Medium Induction Motors)

    The standard load condition shall be no-load. [MG 1-9.5.2] It should be recognized that decibel readings are not exact and are subject to many external influences. For further information see NEMA MG 3-1974 (R1995, R2000, R2006, R2012) Sound Level Prediction for Installed Rotating Electrical Machines.

  • Page 22: Thermal Protection Of Medium Motors

    Condensed MG 1-2011 Page 16 heating. It should be recognized that the number of starts should be kept to a minimum since the life of the motor is affected by the number of starts. [MG 1-12.54] 9.19 Thermal Protection of Medium Motors The protector in a thermally-protected motor shall limit the winding temperature and the ultimate trip current as follows: [MG 1-12.56]...

  • Page 23: Type 2-Winding Running Overtemperature Protection

    Condensed MG 1-2011 Page 17 The temperature of the windings shall be measured by the resistance method except that, for motors rated 15 horsepower and smaller, the temperature shall be permitted to be measured by the thermocouple method. [MG 1-12.57.1.1] 9.20.1.2 Winding Locked-Rotor Temperature...

  • Page 24: Efficiency Of Polyphase Squirrel-Cage Medium Motors With Continuous Ratings

    Nominal Efficiency column in Table 50 which shall be not greater than the average efficiency of a large population of motors of the same design. The efficiency shall be identified on the nameplate by the caption “NEMA Nominal Efficiency” or “NEMA Nom. Eff.”...

  • Page 25: Application Data-Ac Small And Medium Motors

    Condensed MG 1-2011 Page 19 APPLICATION DATA—AC SMALL AND MEDIUM MOTORS 10.1 Service Conditions The following service conditions are defined as “usual”: An ambient temperature in the range of -15°C to 40°C or, when water cooling is used, 5°C to 40°C.

  • Page 26: Power Factor Correction

    90 hertz is established based on the approximate peak torque capability of greater than 175 percent for NEMA Design A and B motors assuming operation at a constant level of voltage equal to rated voltage from 60 to 90 hertz. For the capability of motors for which the minimum breakdown torque is less than 175 percent, consult the motor manufacturer.

  • Page 27: Current

    Condensed MG 1-2011 Page 21 12.2 Current 12.2.1 Running Current Controls are generally rated in terms of a continuous output current capability, a short term output current, and a peak output current. To properly choose the size of control required in an application, consideration should be given to the peak and transient values in addition to the rms value of motor current, and the manner in which the system is to be operated.

  • Page 28: Resonances, Sound, Vibration

    Condensed MG 1-2011 Page 22 rated frequency in the case when motors are used with pulse-width-modulated PWM controls. For other frequencies the noise levels may be higher. [MG 1-30.2.2.6] 12.6 Resonances, Sound, Vibration When an induction motor is operated from a control, torque ripple at various frequencies may exist over the operating speed range.
  • Page 29 Tables MOTORS COVERED BY THIS GUIDE ..................24 ALTERNATING CURRENT MEDIUM MOTOR ................24 DEGREES PROTECTION INDICATED FIRST SECOND CHARACTERISTIC NUMERALS ....................25 TYPICAL METHODS OF COOLING (IC CODE) ................26 UNFILTERED VIBRATION LIMITS ....................26 HORSEPOWER AND SPEED RATINGS, SMALL INDUCTION MOTORS ........26 HORSEPOWER AND SPEED RATINGS, SINGLE-PHASE MEDIUM MOTORS ......
  • Page 30 50 EFFICIENCY LEVELS ........................56 51 FULL-LOAD EFFICIENCIES OF ENERGY EFFICIENT MOTORS ..........57 52 FULL-LOAD EFFICIENCIES FOR 60 Hz NEMA PREMIUM® EFFICIENCY ELECTRIC MOTORS RATED 600 VOLTS OR LESS (RANDOM WOUND) ........... 58 53 FULL-LOAD EFFICIENCIES FOR 60HZ NEMA PREMIUM® EFFICIENCY ELECTRIC MOTORS RATED 5000 VOLTS OR LESS (FORM WOUND ............
  • Page 31 Figures [MG 1 Figure 1-1] PROBE......................63 [MG 1 Figure 1-2] PROBE......................63 [MG 1 Figure 4-2] LETTER SYMBOLS FOR FOOT-MOUNTED MACHINES—DRIVE END VIEW ............................ 64 [MG 1 Figure 4-1] LETTERING OF DIMENSION SHEETS FOR FOOT-MOUNTED MACHINES, SIDE VIEW ........................ 65 [MG 1 Figure 4-3] LETTERING OF DIMENSION SHEETS FOR TYPE C FACE- MOUNTING FOOT OR FOOTLESS MACHINES ................
  • Page 33 Condensed MG 1-2011 Page 23 © 2014 National Electrical Manufacturers Association...

  • Page 34: Motors Covered By This Guide

    Condensed MG 1-2011 Page 24 Table 1 MOTORS COVERED BY THIS GUIDE [MG 1-12.0] Synchronous Speed Motors, Squirrel-cage, HP 3600 1800 1200 Table 2 ALTERNATING CURRENT MEDIUM MOTOR [MG 1 Table 1–1] Synchronous Speed, RPM Motors HP 1201-3600 901-1200 721-900...

  • Page 35: Degrees Of Protection Indicated By The First And Second Characteristic Numerals

    Condensed MG 1-2011 Page 25 Table 3 DEGREES OF PROTECTION INDICATED BY THE FIRST AND SECOND CHARACTERISTIC NUMERALS [MG 1 Table 5-1 & 5-2] First Second Characteristic Characteristic Numeral Brief Description Brief Definition Numeral Brief Description Brief Definition Non-protected motor No special protection.

  • Page 36: Typical Methods Of Cooling (Ic Code)

    Condensed MG 1-2011 Page 26 Table 4 TYPICAL METHODS OF COOLING (IC CODE) Circuit Primary Method of Secondary Method of NEMA Arrangement Coolant Movement Coolant Movement WP-I WP-II TEFC (guarded) TEBC TENV TEAO Complete designation — full description (3 or 5 numerals or letters {numeral letter numeral [letter numeral]} Simplified designation —...

  • Page 37: Horsepower And Speed Ratings, Single-Phase Medium Motors

    Condensed MG 1-2011 Page 27 Table 7 HORSEPOWER AND SPEED RATINGS, SINGLE-PHASE MEDIUM MOTORS [MG 1 Table 10-3] 60-Hertz 50-Hertz Synchronous Speed Synchronous Speed — — — — — 1000 — — — 1200 1500 1000 — 1800 1200 3000...

  • Page 38: Horsepower And Speed Ratings, Polyphase Medium Induction Motors

    Condensed MG 1-2011 Page 28 Table 8 HORSEPOWER AND SPEED RATINGS, POLYPHASE MEDIUM INDUCTION MOTORS [MG 1 Table 10-4] 60-Hertz 50-Hertz Synchronous Rpm Synchronous Rpm — — — — — — — — — — 1200 1000 — — 1800...

  • Page 39: Breakdown Torque For Induction Motors

    Condensed MG 1-2011 Page 29 Table 9 BREAKDOWN TORQUE FOR INDUCTION MOTORS, EXCEPT PERMANENT-SPLIT CAPACITOR MOTORS*† [MG 1 T 10-5] ABLE Frequencies, Hertz 3600 3000 1800 1500 1200 1000 Synchronous Speeds, Rpm Small Motors, Nominal Speeds, 3450** 2850** 1725** 1425**...

  • Page 40: Breakdown Torque For Permanent-Split Capacitor Motors

    Condensed MG 1-2011 Page 30 Table 10 BREAKDOWN TORQUE FOR PERMANENT-SPLIT CAPACITOR MOTORS FOR FAN AND PUMP APPLICATIONS*† [MG 1 T 10-6] ABLE Frequencies, Hertz Synchronous Speeds, 1800 1500 1200 1000 Small Motors, Approximate Full-Load Speeds, Rpm * See 10.32.1 and 10.32.2.

  • Page 41: Typical Characteristics And Applications Of Fixed Frequency Small And Medium Ac Squirrel-Cage Induction Motors

    Condensed MG 1-2011 Page 31 Table 11 TYPICAL CHARACTERISTICS AND APPLICATIONS OF FIXED FREQUENCY SMALL AND MEDIUM AC SQUIRREL-CAGE INDUCTION MOTORS Locked Locked Rotor Pull-Up Breakdown Rotor Torque Torque Torque Current (Percent (Percent (Percent (Percent Polyphase Rated Load Rated Load...

  • Page 42: Code Letters (For Locked-Rotor Kva)-Nameplate Marking

    Condensed MG 1-2011 Page 32 Table 12 CODE LETTERS (FOR LOCKED-ROTOR KVA)—NAMEPLATE MARKING [MG 1-10.37.2] Letter Designation kVA per Horsepower* Letter Designation kVA per Horsepower* 0-3.15 8.0-9.0 3.15-3.55 9.0-10.0 3.55-4.0 10.0-11.2 4.0-4.5 11.2-12.5 4.5-5.0 12.5-14.0 5.0-5.6 14.0-16.0 5.6-6.3 16.0-18.0 6.3-7.1 18.0-20.0...

  • Page 43: Frame Designations For Single-Phase, Design L, Horizontal And Vertical Motors, 60 Hertz, Class B Insulation System, Open Type, 1.15 Service Factor, 230 Volts And Less

    Condensed MG 1-2011 Page 33 Table 14 FRAME DESIGNATIONS FOR SINGLE-PHASE, DESIGN L, HORIZONTAL AND VERTICAL MOTORS, 60 HERTZ, CLASS B INSULATION SYSTEM, OPEN TYPE, 1.15 SERVICE FACTOR, 230 VOLTS AND LESS [MG 1-13.1] Speed, Rpm 3600 1800 1200 —...

  • Page 44: Frame Designations For Polyphase, Squirrel-Cage, Design C

    Condensed MG 1-2011 Page 34 Table 16 FRAME DESIGNATIONS FOR POLYPHASE, SQUIRREL-CAGE, DESIGNS A AND B HORIZONTAL AND VERTICAL MOTORS, 60 HERTZ, CLASS B INSULATION SYSTEM, TOTALLY-ENCLOSED FAN-COOLED TYPE, 1.00 SERVICE FACTOR, 575 VOLTS AND LESS* [MG 1-13.3] Speed, Rpm...

  • Page 45: Frame Designations For Polyphase, Squirrel-Cage, Design C, Horizontal And Vertical Motors, 60 Hertz, Class B Insulation System, Totally Enclosed Fan-Cooled Type, 1.0 Service Factor, 575 Volts And Less

    Condensed MG 1-2011 Page 35 Table 18 FRAME DESIGNATIONS FOR POLYPHASE, SQUIRREL-CAGE, DESIGN C, HORIZONTAL AND VERTICAL MOTORS, 60 HERTZ, CLASS B INSULATION SYSTEM, TOTALLY ENCLOSED FAN- COOLED TYPE, 1.0 SERVICE FACTOR, 575 VOLTS AND LESS* [MG 1-13.5] Speed, Rpm...

  • Page 46: Lettering Of Dimension Sheets

    Condensed MG 1-2011 Page 36 Table 19 LETTERING OF DIMENSION SHEETS [MG1-4.1] NEMA Letter Letter Dimension Indicated Overall dimension across feet of horizontal machine (end view) Overall dimension across feet of horizontal machine (side view) Overall length of single shaft extension machine (For overall length of double shaft extension machine, see letter dimension FC.)

  • Page 47: Dimensions For Alternating-Current Foot-Mounted Motors With Single Straight-Shaft Extension

    Condensed MG 1-2011 Page 37 Table 20 1, 2, DIMENSIONS FOR ALTERNATING-CURRENT FOOT-MOUNTED MOTORS WITH SINGLE STRAIGHT-SHAFT EXTENSION [MG 1-4.4.1] Keyseat Frame E† 2F† H† AA Min†† Designation A Max BA*** V Min ES Min — 2.62 1.75 1.69 2.06 0.28 slot...
  • Page 48 Condensed MG 1-2011 Page 38 (Table 20 Continued.) All dimensions in inches. *The tolerances on the D dimension for rigid base motors shall be +0.00 inch, -0.06 inch. No tolerance has been established for the D dimension of resilient mounted motors.

  • Page 49: Shaft Extensions And Key Dimensions For Alternating-Current Foot

    Condensed MG 1-2011 Page 39 Table 21 SHAFT EXTENSIONS AND KEY DIMENSIONS FOR ALTERNATING-CURRENT FOOT-MOUNTED MOTORS WITH SINGLE TAPERED 1, 2 OR DOUBLE STRAIGHT/TAPERED SHAFT EXTENSION [MG 1-4.4.2] Drive End—Tapered Shaft Extension* Shaft Keyseat Frame Designation Z Max Threads Width...
  • Page 50 Condensed MG 1-2011 Page 40 Table 22 1, 2, 3 DIMENSIONS FOR TYPE C FACE-MOUNTING FOOT OR FOOTLESS ALTERNATING-CURRENT MOTORS [MG 1-4.4.4] Frame Designation* BF Hole Bolt Penetration Keyseat AJ** BB Min BD Max Number Tap Size Allowance ES Min 5.00††...

  • Page 51: Dimensions For Type Dflange-Mounting Foot Or Footless

    Condensed MG 1-2011 Page 41 Table 23 1, 2, 3, 4 DIMENSIONS FOR TYPE D FLANGE-MOUNTING FOOT OR FOOTLESS ALTERNATING-CURRENT MOTORS [MG 1-4.4.6] BF Hole Recom- mended Keyseat Bolt Frame Designation BD Max Number Size Length ES Min 143TD and 145TD 10.00...

  • Page 52: Alternating-Current Motors

    Condensed MG 1-2011 Page 42 Table 24 DIMENSIONS FOR TYPE FC FACE MOUNTING FOR ACCESSORIES ON END OPPOSITE DRIVE END OF 1, 2 ALTERNATING-CURRENT MOTORS [MG 1-4.4.5] FBF Hole Hole for Accessory Leads†† Bolt Penetration Frame Designations FBB Min FBD Min...

  • Page 53: Locked-Rotor Torque Of Single-Phase Small Motors

    Condensed MG 1-2011 Page 43 Table 27 LOCKED-ROTOR TORQUE OF SINGLE-PHASE SMALL MOTORS [MG 1-12.32.2] INIMUM OCKED OTOR ORQUE UNCE 60-Hertz Synchronous Speed, RPM 50-Hertz Synchronous Speed, RPM 3600 1800 1200 3000 1500 1000 — — — — — —...

  • Page 54: Locked-Rotor Current Of Single-Phase Medium Motors, Designs L And M

    Condensed MG 1-2011 Page 44 Table 30 LOCKED-ROTOR CURRENT OF SINGLE-PHASE MEDIUM MOTORS, DESIGNS L AND M [MG 1-12.34] Locked-Rotor Current, Amperes Design L Motors Design M Motors 115 Volts 230 Volts 230 Volts — — — — 1-1/2 —...

  • Page 55: Locked-Rotor Torque Of Design A And B Motors

    Condensed MG 1-2011 Page 45 Table 32 LOCKED-ROTOR TORQUE OF DESIGN A AND B MOTORS [MG 1-12.38.1] Synchronous Speed, Rpm 60 Hertz 3600 1800 1200 — — — 50 Hertz 3000 1500 1000 — — — — — — 1-1/2 7-1/2 —...

  • Page 56: Breakdown Torque Of Design A And B Motors

    Condensed MG 1-2011 Page 46 Table 34 BREAKDOWN TORQUE OF DESIGN A AND B MOTORS [MG 1-12.39.1] Synchronous Speed, Rpm 60 Hertz 3600 1800 1200 — — — 50 Hertz 3000 1500 1000 — — — — — — 1-1/2...

  • Page 57: Pull-Up Torque Of Design A And B Motors

    Condensed MG 1-2011 Page 47 Table 36 PULL-UP TORQUE OF DESIGN A AND B MOTORS [MG 1-12.40.1] Synchronous Speed, Rpm 60 Hertz 3600 1800 1200 — — — 50 Hertz 3000 1500 1000 — — — — — — 1-1/2 7-1/2 —...

  • Page 58: Pull-Up Torque Of Design C Motors

    Condensed MG 1-2011 Page 48 Table 37 PULL-UP TORQUE OF DESIGN C MOTORS [MG 1-12.40.2] Pull-Up Torque, Percent of Full-Load Torque Synchronous Speed, Rpm 60 Hertz 1800 1200 50 Hertz 1500 1000 1-1/2 7-1/2 © 2014 National Electrical Manufacturers Association...

  • Page 59: Temperature Rise For Small And Medium Single-Phase And Polyphase Induction Motors

    Condensed MG 1-2011 Page 49 Table 38 TEMPERATURE RISE FOR SMALL AND MEDIUM SINGLE-PHASE AND POLYPHASE INDUCTION MOTORS Alternating-Current Small Motors—Motor Nameplates Marked with Insulation System Designation and Ambient Temperature [MG 1-12.42.1] Class of Insulation System (see MG 1 Part 1) Time Rating (See page 9.)

  • Page 60: Service Factors Of General-Purpose Alternating-Current Motors Of The Open Type

    Condensed MG 1-2011 Page 50 Table 39 SERVICE FACTORS OF GENERAL-PURPOSE ALTERNATING-CURRENT MOTORS OF THE OPEN TYPE [MG 1 Table 12-4] Synchronous Speed, Rpm 3600 1800 1200 — — — 1.35 1.35 1.35 1.35 Small — — — Motors 1.35 1.35...

  • Page 61: Continuous Speed Capability For General-Purpose Squirrel-Cage

    Condensed MG 1-2011 Page 51 Table 41 CONTINUOUS SPEED CAPABILITY FOR GENERAL-PURPOSE SQUIRREL-CAGE INDUCTION MOTORS IN DIRECT COUPLED APPLICATIONS, EXCEPT THOSE MOTORS IN 9.16.2 [MG 1 Table 12-5] Totally Enclosed Fan-Cooled Open Dripproof Synchronous Speed at 60 Hz Synchronous Speed at 60 Hz...

  • Page 62: Continuous Speed Capability For General-Purpose Design A And Bdirect Coupled (Ts Shaft For Motors Above The 250 Frame Size) Squirrel-Cage Induction Motors

    Condensed MG 1-2011 Page 52 Table 42 CONTINUOUS SPEED CAPABILITY FOR GENERAL-PURPOSE DESIGN A AND B DIRECT COUPLED (TS SHAFT FOR MOTORS ABOVE THE 250 FRAME SIZE) SQUIRREL-CAGE INDUCTION MOTORS [MG 1 Table 12-6] Totally Enclosed Fan-Cooled Open Dripproof Synchronous Speed at 60 Hz...

  • Page 63: Maximum A-Weighted Sound Power Levels, L Wa (Db), At No-Load

    Condensed MG 1-2011 Page 53 Table 43 MAXIMUM A-WEIGHTED SOUND POWER LEVELS, L (dB), AT NO-LOAD [MG 1 Table 9-1] Rated Speed Rated Power, 1801- 3600 RPM 1201- 1800 RPM 901 - 1200 RPM 900 RPM or less Motor HP...

  • Page 64: Incremental Expected Increase Over No-Load Condition, In A-Weighted Sound Power Levels L

    Condensed MG 1-2011 Page 54 Table 44 INCREMENTAL EXPECTED INCREASE OVER NO-LOAD CONDITION, IN A-WEIGHTED SOUND POWER LEVELS L (dB) , FOR RATED LOAD CONDITION FOR SINGLE-SPEED, THREE-PHASE, SQUIRREL-CAGE, INDUCTION MOTORS [MG 1 Table 9-3] Rated Output, P 2 Pole...

  • Page 65: Winding Temperatures Under Running Load Conditions

    Condensed MG 1-2011 Page 55 Table 46 WINDING TEMPERATURES UNDER RUNNING LOAD CONDITIONS [MG 1 Table 12-8] Insulation Maximum Winding Temperature, System Class Degrees C Table 47 WINDING TEMPERATURE UNDER LOCKED-ROTOR CONDITIONS [MG 1 Table 12-9] Maximum Temperature, Degrees C*...

  • Page 66: Efficiency Levels

    Condensed MG 1-2011 Page 56 Table 50 EFFICIENCY LEVELS [MG 1 Table 12-10] Column B Column B Column A Minimum Efficiency Column A Minimum Efficiency Nominal Based on 20% Nominal Based on 20% Efficiency Loss Difference Efficiency Loss Difference 99.0 98.8...

  • Page 67: Full-Load Efficiencies Of Energy Efficient Motors

    Condensed MG 1-2011 Page 57 Table 51 FULL-LOAD EFFICIENCIES OF ENERGY EFFICIENT MOTORS [MG 1 Table 12-11] 2 POLE 4 POLE 6 POLE 8 POLE Nominal Minimum Nominal Minimum Nominal Minimum Nominal Minimum Efficiency Efficiency Efficiency Efficiency Efficiency Efficiency Efficiency...

  • Page 68: Full-Load Efficiencies For 60 Hz Nema Premium® Efficiency Electric Motors Rated 600 Volts Or Less (Random Wound)

    Condensed MG 1-2011 Page 58 Table 52 FULL-LOAD EFFICIENCIES FOR 60 Hz NEMA PREMIUM® EFFICIENCY ELECTRIC MOTORS RATED 600 VOLTS OR LESS (RANDOM WOUND) [MG 1 Table 12-12] 2 POLE 4 POLE 6 POLE 8 POLE Nominal Minimum Nominal Minimum...

  • Page 69: Full-Load Efficiencies For 60Hz Nema Premium® Efficiency Electric Motors Rated 5000 Volts Or Less

    Condensed MG 1-2011 Page 59 Table 53 FULL-LOAD EFFICIENCIES FOR 60HZ NEMA PREMIUM® EFFICIENCY ELECTRIC MOTORS RATED 5000 VOLTS OR LESS (FORM WOUND) [MG 1 Table 12-13] 2 POLE 4 POLE 6 POLE Nominal Minimum Nominal Minimum Nominal Minimum Efficiency...

  • Page 70: Full-Load Efficiencies For 50 Hz Nema Premium Efficiency Electric Motors Rated 600 Volts Or Less (Random Wound)

    Condensed MG 1-2011 Page 60 Table 54 FULL-LOAD EFFICIENCIES FOR 50 HZ NEMA PREMIUM EFFICIENCY ELECTRIC MOTORS RATED 600 VOLTS OR LESS (RANDOM WOUND) [MG1-T 12-14] ABLE OPEN MOTORS 2 POLE 4 POLE 6 POLE Nominal Minimum Nominal Minimum Nominal...
  • Page 71 Condensed MG 1-2011 Page 61 TABLE 54 (C ONTINUED  FULL-LOAD EFFICIENCIES FOR 50 HZ NEMA PREMIUM EFFICIENCY ELECTRIC MOTORS RATED 600 VOLTS OR LESS (RANDOM WOUND) [MG1- T 12-14] ABLE ENCLOSED MOTORS 2 POLE 4 POLE 6 POLE Nominal...

  • Page 72: Maximum Safe Operating Speed For Standard Design A And B Direct Drive (Ts Shaft For Frames Over 250) Squirrel-Cage Induction Motors

    Condensed MG 1-2011 Page 62 Table 55-4 MAXIMUM SAFE OPERATING SPEED FOR STANDARD DESIGN A AND B DIRECT DRIVE (TS SHAFT FOR FRAMES OVER 250) SQUIRREL-CAGE INDUCTION MOTORS [MG 1 Table 30-1] Totally Enclosed Fan-Cooled Open Dripproof Synchronous Speed at 60 Hz...
  • Page 73 Condensed MG 1-2011 Page 63 Figure 1 [MG 1 Figure 1-1] PROBE Figure 2 [MG 1 Figure 1-2] PROBE © 2014 National Electrical Manufacturers Association...
  • Page 74 Condensed MG 1-2011 Page 64 Figure 3 [MG 1 Figure 4-2] LETTER SYMBOLS FOR FOOT-MOUNTED MACHINES—DRIVE END VIEW © 2014 National Electrical Manufacturers Association...
  • Page 75 Condensed MG 1-2011 Page 65 Figure 4 [MG 1 Figure 4-1] LETTERING OF DIMENSION SHEETS FOR FOOT-MOUNTED MACHINES, SIDE VIEW © 2014 National Electrical Manufacturers Association...
  • Page 76 Condensed MG 1-2011 Page 66 Figure 5 [MG 1 Figure 4-3] LETTERING OF DIMENSION SHEETS FOR TYPE C FACE-MOUNTING FOOT OR FOOTLESS MACHINES © 2014 National Electrical Manufacturers Association...
  • Page 77 Condensed MG 1-2011 Page 67 Figure 6 [MG 1-4.4.5] Figure 7 [MG 1 Figure 14-1] MEDIUM MOTOR DERATING FACTOR DUE TO UNBALANCED VOLTAGE © 2014 National Electrical Manufacturers Association...
  • Page 78 Condensed MG 1-2011 Page 68 PERCENT RATED LOAD Figure 8 [MG 1 Figure 14-2] TYPICAL EFFICIENCY VERSUS LOAD CURVES FOR 1800 RPM THREE-PHASE 60-HERTZ DESIGN B SQUIRREL-CAGE INDUCTION MOTORS Figure 9 [MG 1 Figure 30-1] DERATING CURVE FOR HARMONIC VOLTAGES §...

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