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MOTOR NAMEPLATE INFORMATION

The motor nameplate is a description from the manufacturer listing specific information about themotors characteristics.

C Motor standards require motors to be shipped with a nameplate when new.

C The National Electrical Code requires specific items on a motor nameplate including:manufacturer, voltage, full load amps, frequency, phase, RPM, temperature rise or insulationclass and ambient temperature, duty rating, rated horsepower, and locked rotor design letter.

C Additional information will normally appear including service factor, enclosure type, framesize, connection diagrams, and other unique or special features.

ELECTRIC MOTOR NAMEPLATE

MODEL 500 SPLIT PHASE TOTALLY ENCLOSED

FRAME TYPE INS. CLASS IDENTIFICATION NO.

145 KC J 2538094990298209

HP RPM VOLTS AMPS CYC S.F.

1 ½ 1725 115/230 15/7.5 60 1.25

DESIGN CODE: B PHASE EFF p.f.

DRIVE END BEARING BBD 116 1 62% 75%

OPP. END BEARING B0B 117 DUTY: CONTINUOUS

AMB 40 C NO THERMAL PROTECTION

R Manufacturer's Name, Model, & Serial #C The manufacturer's name identifies the manufacturer of the motor.C Model number identifies the model of the motor produced by the specific manufacturer.C Serial number is specific for the manufacturer and identifies the specific motor and is useful

in establishing the age of the motor for replacement parts and warranties.

R Motor TypeIdentifies the type of motor/generally describes the starting method including:

DC Motors: Shunt Wound, Series Wound, Compound Wound, Permanent Magnet, Universal

Single Phase Motors: Split Phase, Shaded Pole, Permanent Split Capacitor, Capacitor Start,Capacitor Start-Capacitor Run, Universal.

Three Phase Motors: Squirrel Cage Induction, Wound Rotor, Synchronous, Reluctance

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R Enclosure Type

The enclosure for the motor should be chosen to protect it from the expected operating environment.

• Electric motors are required to operate in many different environments ranging from cleanand dry to extremely dirty, wet, and corrosive or from normal to very high temperatures.

C Manufacturers provide a variety of motor enclosures designed to protect against varioustypes of adverse conditions.

• The enclosure for the motor should be chosen to protect it from the expected operatingenvironment. The following table lists standard NEMA enclosures:

Standard Motor Enclosure Ratings

Types Characteristics

Open:Drip-proofSplash-proofGuardedSemi-guardedFully Drip-proofGuarded, externally ventilatedPipe ventilatedWeather protected type 1

Weather protected type 2

Totally Enclosed:Non-ventilated (TENV)Fan-cooled (TEFC)Explosion-proof (TEXP)

Dust-ignition proof

WaterproofPipe-ventilatedWater-cooledWater to air-cooledAir-to-air cooledGuarded TEFCEncapsulated

Operate with dripping liquids up to 15E from vertical.Operate with splashing liquids up to 100E from vertical.Guarded by limited size openings (less than 3/4 in).Only top half of motor guarded.Drip-proof motor with limited size openings.Ventilated with separate motor-driven blower, can have othertypes of protection.Openings accept inlet ducts or pipe for air cooling.Ventilating passages minimize entrance of rain, snow, andairborne particles. Passages are less than 3/4 in. in diameter.Motors have, in addition to type 1, passages to dischargehigh-velocity particles blown into the motor.

Not equipped for external cooling.Cooled by external integral fan.Withstands internal gas explosion. Prevents ignition ofexternal gas.Excludes ignitable amounts of dust and amounts of dust thatwould degrade performance.Excludes leakage except around shaft.Openings accept inlet ducts or pipe for air cooling.Cooled by circulating water.Cooled by water-cooled air.Cooled by air-cooled air.Fan cooled and guarded by limited-size openings.Has resin-filled windings for severe operating conditions.

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R NEMA Frame Size Designation

NEMA has assigned a series of standardized numbersand letters to describe various dimensions andmounting types of motor frames.

C When changing a motor, selecting the sameframe size regardless of manufacturer ensuresthe mounting mechanism and hole positionswill match.

C As a general rule, as frame size increases, sodoes physical size and horsepower of the motor.

C There are many motors of the same horsepower and size built with different frame sizes sothey can be mounted in various manners.

NEMA Frame Designations

The standard NEMA Frame Size designation may contain:C a prefix of lettersC the frame numberC a suffix of letters

Frame Size Prefix

Letters or numbers appearing in front of the NEMA Frame Designation are the manufacturer’s. They are not standardized within the NEMA designation and importance/meaning varies bymanufacturer.

Example: EF56C

C The EF in the frame Designation EF56C is a manufacturers prefix indicating somethingabout the particular motor compared to other models produced by the same manufacturer.

Frame Size Number

In any standard frame number designation there are either two orthree numbers.

S Two Digit Frame Size - Indicates a fractional horsepowermotor less than 1 horsepower.

C If the nameplate displays a two digit frame number, thenumber is the distance from the center of the drive shaft tothe center bottom of the mount in sixteenths of an inch.

Example: EF56C > 56 divided by 16 = 3.5 inches from shaft to mount.

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S Three Digit Frame Size - indicates an integral horsepower motor 1 horsepower or greater.

C For three digit frame sizes, divide the first two digits by fourto calculate the distance from the center of the drive shaft tothe center bottom of the mount in fourths of an inch.

Example: EF145C, > 14 divided by 4 = 3.5inches from shaft tomount.

C The third digit is an indication of the distance between themounting holes parallel to the base.

Example: EF145C, > Mounting holes are 5 inches apart.

Frame Size Suffix

The suffix letter in the frame designation indicates the mounting type of the motor.

C Today, new motors are designated "T" frame motors.C Between 1952 and 1964, the NEMA standards designated motors as "U" frame motors.C Prior to 1952, the "Original" standard was used.

Example: 143TD, > A current T-Frame motor using a D-Flange mount.

S No suffix or a T indicates a NEMA standard shaft

C For motors that have a letter following the T:

S S indicates a NEMA standard "short shaft" for belt driven loadsS U would indicate a motor manufactured prior to 1965 meeting previous standards.S Y indicates a non-NEMA standard mount which may be a special base, flange, or

face and a drawing is required to be sure of the dimensions.S Z indicates a non-NEMA standard shaft and a drawing is required to be sure of the

dimensions.S C indicates a standard NEMA face mount having a flat mounting surface machined

on the drive end with holes to allow easy, secure mounting to driven equipment.S D indicates a standard NEMA flange mount having a flat mounting surface machined

on the drive end with holes to allow easy, secure mounting to driven equipment.S H indicates a frame with a rigid base having an F dimension larger than that of the

same frame without the suffix X.S J indicates a NEMA C Face mount with a threaded shaft for a pump motor.S JM, JP and JM indicate a close-coupled pump motor with specific dimensions and

bearings. The three designations differ in specific sizes.S M or N indicates a NEMA mount that has a special flange for direct attachment to

fuel atomizing pumps on oil burners. M indicates a 6 3/4 inch flange while Nindicates a 7 1/4 inch flange.

R Insulation Class

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Type of insulation used in a motor depends on the operating temperature the motor will experience.

C Standard NEMA insulation classes are given by alphabetic classifications according to themaximum temperature rating and include A, B, F, H, or J.

C They are an indication of the maximum temperature the motor insulation can withstandwithout degrading its life.

S Class A insulation was the standard insulation used on older U Frame motors between1952 and 1964.

S T Frame motors produced since 1964 use class B insulation as the standard.

C Do not confuse the NEMA insulation classes with the NEMA motor designs which are alsogiven by letters.

Insulation temperature charts are used to select insulation that will provide dependable motor life.

Example: A motor operating at 180 Degrees C will have an estimated life of:

300 hours with Class A insulation1800 hours with Class B insulation8500 hours with Class F insulationTens of thousands of hours with Class H insulation

R Horsepower Rating

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The full load output power at the shaft the motor can producewithout reducing its operating life.

C If a motor produces more horsepower than it is ratedfor, the service life will be reduced.

C Motors below 1 horsepower are referred to asfractional-horsepower motors and motors 1 horsepowerand above are called integral-horsepower motors.

C NEMA has established standard power ratings fromfractional to thousands of horsepower.

Standard NEMA Horsepower Ratings 1 through 4000 Hp 11.52357.510152025

3040506075100125150200250

3003504004505006007008009001000

125015001750200022502500300035004000

C When an application calls for ahorsepower falling between two sizes,the larger size is chosen to provide theappropriate power to operate the load.

C Motor and engine manufacturers use different tests and definitions when describing “power”.

C Motors have one power rating: Continuous Brake Horsepower

C Engines will have several power ratings.

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R R.P.M.

RPM is the rated operating speed of the motor at full load.

C Normal operating speeds for 60 hertz and 50hertz motors vary depending on the numberof poles in the motor stator.

C Some motors are dual speed motors and boththe speeds will be given.

C The motor may be one of the followingNEMA classifications of speedcharacteristics:

Constant Speed Motor:

One in which the speed of normal operation is constant or practically constant.

C Examples include synchronous motors, induction motors with small slip design, or a DCshunt wound motor.

Multi speed Motor:

One which can be operated at any two or more definite speeds, each being independent of the loadpower required.

C Examples include DC motors with more than two armature windings and AC inductionmotors with windings capable of various pole groupings to accomplish the specific differentspeeds.

Varying Speed Motor:

One in which speed varies with the load, ordinarily decreasing as the load increases or increasing asthe load decreases.

C Examples include series wound DC or repulsion AC motors.

Adjustable Varying Speed Motor:

One in which speed can be adjusted gradually, but once adjusted for a given load, will vary with thechange in load.

C Examples include a wound rotor motor with an adjustable rheostat speed control.

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R Duty Rating

Motors are classified according to the lengthof time expected to operate under full load.

C The motor may be rated as either:

1. Continuous Duty2. Intermittent Duty

Continuous Duty Motors

Continuous duty rated motors are rated to berun continuously without any damage orreduction in life of the motor.

C General purpose motors willnormally be rated for continuous duty.

Intermittent Duty Motors

Intermittent duty motors are rated to be run continuously only for short time periods and then mustbe allowed to stop and cool before restarting.

C It is usually possible to reducethe size, weight, and cost of amotor by purchasing anintermittent duty motor.

C Intermittent duty motors areavailable with maximumoperating times of 5, 15, 30, or60 minute duties or times.

C These motors are sometimesused on devices like garbagedisposals or air compressorswhere the motor operates for ashort period and shuts off afterthe job is accomplished and willnot be needed for an extendedtime period.

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R Phase

Phase describes the necessary phase of the electricpower supply required for correct connection andoperation of the motor - Single or Three Phase.

C Motors are designed for either single or threephase operation as indicated on the nameplate.

Single Phase Motors

Single phase motors in general may be operated on onephase of a three phase power supply with the correct rated voltage.

C Single phase motors are used in smaller motor sizes, especially those less than 1 horsepoweror where three phase power is not available.

C Single phase motors make up 80 percent of the U.S. motor market and are generally less than10 horsepower in size unless special equipment or situations are applied.

Advantages of Three Phase Motors

C Little or no voltage flicker when starting the motor.C Cost less to purchase than comparable size single phase motors.C Have longer life spans than single phase motors.

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R Rated Voltage(s)

This is the electrical supply voltage(s) at whichthe motor is rated to operate.

C AC motors are designed for optimumperformance with a specific voltageapplied from the electrical system.

NEMA Standard Motor Voltages

Single Phase Motors115, 230, 115/230, 277, 460, and 230/460

Three Phase Motors up to 125 Hp208, 230, 460, 230/460, 575, 2300, and 4000

Three Phase Motors above 125 Hp460, 575, 2300, and 4000 volts

C When dealing with motors, it is important to understand the difference between nominalsystem and nameplate voltages.

NominalSystemVoltage

NameplateVoltage

120208240480600240041606900

115200230460575230040006600

C Some older NEMA motors rated for 200, 220,440 or 550 volts are sometimes encountered.

C Motors with these markings can safely bereplaced by motors having the current NEMAmarkings of 208, 230/460 or 575 volts.

C Motors rated 115/230 volts and 230/460 voltsin most cases will operate satisfactorily on a208 volt system but the torque will be 20 to25% lower.

C Operating below 208 volts may require a 208 Volt (200 Volt) motor or the use of the nexthigher horsepower standard voltage motor.

Since line voltage will vary over a period of time due to power system load conditions, a motor mustcope with some voltage variation.

C Standard motors are designed to tolerate voltage variations of plus or minus 10 percent.

S A motor with a nameplate voltage of 230 volts could be expected to give satisfactoryperformance from 207 volts to 253 volts.

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R Hertz or Frequency

Identifies the rated frequency of the power sourceto be used in cycles per second.

C Motors intended for the North Americanmarket are designed for operation on 60hertz frequencies.

C 50 hertz indicates a motor made for exportout of the North American market.

C NEMA standards specify motors shouldoperate satisfactorily under frequencyvariations up to + 5% of rated frequency.

C Operation outside of this limit results in a substantial speed variation and may causeoverheating and reduced torque.

R Current (Amperage) Rating

This is the motors rated current at full load and ratedvoltage.

Other terms:

C Full Load Amps (FLA)C Running Load Amps (RLA)

C The motor will draw the rated current whenproducing its rated output power whensupplied its rated voltage

C When a motor draws more current than it israted, the motor is overloaded unless the motor has a service factor larger than 1.0.

C Motor's drawing more current than their rated will generally have their windings damageddue to the additional heat and the motor’s life will be reduced.

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R Service Factor

NEMA defines service factor as the amount of continual overload capacity designed into a motor.

C It is the amount of overload over the nameplate rated power the motor can toleratecontinuously at rated voltage and speed without reducing its life.

S An indication of the motor's ability to exceed the mechanical power output rating on asustained basis without overloading or motor damage provided other serviceparameters such as voltage, frequency, and ambient temperature are within norms.

S Service factor is a function of insulation class. Using Class F or H insulation insteadof Class B insulation allows the motor to withstand more internal heat withoutreducing its operating life.

C A service factor greater than 1.0 allows a margin for peak horsepower demand withoutselecting the next larger motor size.

C FLA can be multiplied by the service factor to determine the maximum current loading.

C NEMA lists standard service factors for various size motors however many manufacturersbuild and market motors with higher service factors than the NEMA standard.S Common motor Service Factors include: 1.0, 1.15 and 1.25

C Do not replace a motor of the same nameplate horsepower with one with a lower servicefactor unless you know the new motor will not be overloaded.

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R Design Code Letter

An alphabetic letter used to indicate theNational Electric Code Design Code letter forthe motor.

C When AC motors are started with fullvoltage applied, they draw “in-rush’ linecurrents substantially greater than theirfull load running current rating.

C The Code letter of the motor is anindication of the locked rotor KVA perhorsepower for the particular motor andis a function of the motors design.

The code letter rating gives a good indication of the starting current a particular motor will draw.

C A code letter at the beginning of the alphabet indicates a low starting current and a letterlower than F indicates a high starting current for the particular motor.

C The motor's Code Letter is helpful in determining the maximum rating of the motor'selectrical circuit protection.

C A replacement motor should have the same rating as its predecessor or the circuitfuses/breakers and wire may not be sized appropriately and have to be replaced.

Code Letters for Locked Rotor kVA are as follows:

CodeLetter KVA/Hp A: 0.00-3.14 B: 3.15-3.54 C: 3.55-3.99 D: 4.00-4.49 E: 4.50-4.99 F: 5.00-5.59 G: 5.60-6.29

CodeLetter KVA/Hp H: 6.30-7.09 J: 7.10-7.99 K: 8.00-8.99 L: 9.00-9.99 M: 10.00-11.19 N: 11.20-12.49 P: 12.50-13.99

CodeLetter KVA/Hp R: 14.00-15.99 S: 16.00-17.99 T: 18.00-19.99 U: 20.00-22.39 V: 22.40-AND UP

Starting kVA/HP (from chart) X Motor HP 1000 for single phaseLocked Rotor Amps = ------------------------------------------------------ X or

Rated Volts 577 for 3 phase

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R Power Factor

The motor's power factor at rated load and voltage.

C Motors are inductive loads and have power factors less than 1.0, usually between 0.5 and0.95 depending on their rated size.

S The higher the rated horsepower, in general the higher the power factor of the motor.

• Most AC motors require reactive power from the supply system to develop magnetic fields.

S Reactive power does not provide any useful mechanical work but is required to makethe motor operate.

S Useful mechanical work is developed from Real Power (kW) supplied by the supplysystem and is measured in kilowatts.

S The electrical supply system must provide both Real (kW) and Reactive Power(kVAR) to operate the motor.

• The power factor of induction motors varies with load and drops significantly below 75%load.

• Some utilities chargepenalties if plant powerfactor is below a certainpercent.

C This gives the customeran incentive to applypower factor correction(capacitors).

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R Connection Diagram

Connection diagrams can be found on thenameplate of some motors, or the diagram may belocated inside the motor conduit box or on a specialconnection plate.

C The diagram will indicate the specificconnections for dual voltage rated motors.

C The diagram may also provide the standarddirection of rotation for the motor shaft, clockwise, or counter clockwise.

C Unless stated otherwise, rotation is specified from the end view of the shaft extension.

C Some motors can operate in either direction depending on how the connections to the motorare made and this information may also be given on the nameplate.

R Ambient Temperature

The abbreviation AMB on a motor nameplate provides the maximum ambient temperature the motorshould be operated within.

C Ambient means the temperature of the air surrounding the motor.

C In general, maximum ambient temperature for motors is 40 Degrees C or 104 Degrees Funless the motor is specifically designed for a different temperature and indicates so on thenameplate.

C Operation of a motor at ambient temperatures above that given on the nameplate may or maynot affect the life of the motor depending on whether the motor is operating at or near itsrated full load.

C Motors operating at or near rated full load will have reduced life if operated at ambienttemperatures above their ratings.

• If the ambient temperature is over 104 degrees F, a higher horsepower motor or a specialmotor designed for operation at higher ambient temperatures must be used.

• Motors for use in abnormally hot places are usually designed to accommodate the higherambient by having a lower winding temperature rise.

• If the ambient temperature is above 122 degrees F, special consideration must also be madeof the lubricant.

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R Temperature Rise

Temperature rise is the increase in the motorsinternal temperature as it operates due to currentflowing through the windings.

C The ambient temperature plus thetemperature rise is the maximum temperatureat which the motor should operate at fullload.

C It can also be thought of as the amount whicha motor operating under rated conditions, ishotter than its surrounding temperature.

C The ambient temperature has very little, if anything, to do with the motors actual temperaturerise.

C Certain inaccessible spots of a motor winding are considered to be the hottest spots of theinsulation system. These areas are called hot spots.

S For the reason a 10 Degrees C allowance is made for uneven heating in the motorcalled a hot spot allowance.

S The total temperature rise equals the rise due to the load on the motor plus the hotspot allowance.

S Generally you do not have any control over temperature rise due to load or hot spotallowance.

C However, you can limit motor temperature and maximize life by selecting a motor that canproduce enough horsepower without being overloaded and by making sure the motor runs inambient temperatures at or below the nameplate rating.

C A good rule to remember is that for every 10 degrees C the operating temperature increasesover rated temperature, motor life will be cut in half.

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R Thermal Protection

Indicates if the motor has its own internal automatic or manual thermal overload protection device.

C There are several types of protective devices thancan be built into the motor and used to senseexcessive (overload) temperature rise, and/or currentflow.

C These devices disconnect the motor from its powersource if they sense the overload to prevent damageto the insulation of the motor windings.

C This prevents the motor from getting to hot anddamaging the windings or causing a possible fire.

The primary types of thermal overload protectors include automatic and manual reset devices thatsense either current or temperature.

C With automatic reset devices, after the motor cools,this electrical circuit interrupting deviceautomatically restores power to the motor.

C With manual reset devices, the electrical circuitinterrupting device has an external button located onthe motor enclosure that must be manually pressed torestore power to the motor.

C Some low cost motors have no internal thermalprotection and rely on external protection betweenthe motor and the electrical power supply for safety.

Never bypass a thermal protective device because of nuisance tripping of the motor.

C The tripping is generally a sign of some other problem, such as overloading, buildup of dirtand debris, or lack of proper ventilation.

Manual reset protection should be provided where automatic restart of the motor after it cools downcould cause personal injury should the motor start unexpectedly.

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R Efficiency

The efficiency of a motor is the ratio of mechanical power output the motor can produce to theelectrical power input required by the motor.

C Think of this as the useful work the motorproduces versus the energy the motorconsumes expressed as a percentage.

C Most motors operate near their maximumefficiency at rated load.

C Motor efficiency varies from the nameplatevalue depending on the percentage of therated load applied to the motor.

NEMA standard MG1-12 provides instructions for manufacturers in establishing the value ofefficiency for a given size and type of motor.

C The efficiency given on the nameplatecannot exceed the nominal (average)efficiency for a large population ofmotors of the same design when testedby the manufacturer.

C Variations in motor efficiency existfrom motor to motor due tomanufacturing tolerances, raw materialvariations, and process changes.

C It is generally reasonable to expectdifference of + 1% for a motorsefficiency based on the nominalefficiency on the nameplate.

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R Special Order Motors

Electrical motors are classified into several groups depending on the type of service for which theyare designed.

Standard or General Purpose motors

General Purpose motors are designed for general use without restrictions for particular applicationsand meet certain specific NEMA standards.

C General purpose motors are less expensive, use proven designs and are available on shorterlead times than other service classifications of motors.

Definite Purpose Motor

A Definite Purpose Motor is designed in standard ratings and with standard operating characteristicsfor use under service conditions other than usual or for use on a particular type of application.

C Common definite purpose motors include

- automotive industry- chemical industry- food processing industry- farm duty-other categories.

Special Purpose Motor

A Special Purpose Motor is one with special operating characteristics or special mechanicalconstruction or both which is designed for a particular application and which does not meet thedefinition of a general or definite purpose motor.

Special Order Motors

Motors can be ordered with an almost unlimited number of variations to fit special applicationswhere a standard motor is not suitable.

C Each motor supplier is more than happy to provide specific information on availability, leadtime and price for special order motors.