07/08/2002 PP.AFD.02.MotorBasics 1 of 55 Yaskawa Electric America Motor Basics.

11 of 55 of 55PP.AFD.02.MotorBasicsPP.AFD.02.MotorBasics07/08/200207/08/2002

Yaskawa Electric Yaskawa Electric AmericaAmerica

Motor BasicsMotor Basics


Three Phase Motor ConstructionThree Phase Motor Construction

StatorStator

RotorRotor

Windings - ElectromagnetsWindings - ElectromagnetsRotor barsRotor bars



End ViewEnd View

RotorRotor

StatorStator

EnclosureEnclosure

Air GapAir Gap

Stator Stator WindingsWindings

ShaftShaft



End ViewEnd View

T1T1

T2T2

T2’T2’

T3T3

T1’T1’

T3’T3’


Motor OperationMotor Operation








Three Phase Motor ConstructionThree Phase Motor ConstructionT1T1

End ViewEnd View

T2T2

T2’T2’

T3T3

T1’T1’

T3’T3’

+

+

+

+ denotes current denotes current is moving away is moving away from youfrom you

denotes current denotes current is is moving moving towards youtowards you


Rotation of the motorRotation of the motor

+

+

+NN NN

SSSS

SS

NN

T1T1

T3T3

T2T2

One Cycle*One Cycle*

* - current waveform* - current waveform



+

+

+

NNSS

NN

NN

SSSS

T1T1

T3T3

T2T2



+

+

+NN NN

SSSS

SS

NN



++

+

NN

NN

SS

SS

SS

NN

T1T1

T3T3

T2T2



+

+

+NN NN

SSSS

SS

NN

+

+

+

NNSS

NN

NN

SSSS



++

+NN

NN

SS

SS

SS

NN

T1T1

T3T3

T2T2



+

+

+NN NN

SSSS

SS

NN

+

+

+

NNSS

NN

NN

SSSS

++

+

NN

NN

SS

SS

SS

NN



+

+

+NN

NN SS

SS

SS

NN

T1T1

T3T3

T2T2



+

+

+NN NN

SSSS

SS

NN

+

+

+

NNSS

NN

NN

SSSS

++

+

NN

NN

SS

SS

SS

NN+

+

+NN

NN

SS

SS

SS

NN



++

+

NN

NN SS

SS

SS

NN

T1T1

T3T3

T2T2



+

+

+NN NN

SSSS

SS

NN

+

+

+

NNSS

NN

NN

SSSS

++

+

NN

NN

SS

SS

SS

NN+

+

+NN

NN

SS

SS

SS

NN

+

+

+NN

NN SS

SS

SS

NN



+

+

+NN NN

SSSS

SS

NN

T1T1

T3T3

T2T2



+

+

+NN NN

SSSS

SS

NN

+

+

+

NNSS

NN

NN

SSSS

++

+

NN

NN

SS

SS

SS

NN+

+

+NN

NN

SS

SS

SS

NN

+

+

+NN

NN SS

SS

SS

NN

++

+

NN

NN SS

SS

SS

NN


Calculating Synchronous Calculating Synchronous Speed of the MotorSpeed of the Motor

P

fNo

120


Poles & Synchronous RPM @ 60HzPoles & Synchronous RPM @ 60Hz

Magnetic Poles Synchronous RPM2 36004 18006 12008 900

7200= Synchronous RPM

P

7200= P

Synchronous RPM



End ViewEnd View

T2T2

T2’T2’

T3T3

T1’T1’

T3’T3’



End ViewEnd View

T2T2

T2’T2’

T3T3

T1’T1’

T3’T3’



End ViewEnd View

Magnetic Magnetic PolesPoles

T1aT1a

T2aT2a

T2a’T2a’

T1a’T1a’T1bT1b

T2bT2b

T2b’T2b’

T3bT3b

T1b’T1b’

T3b’T3b’

T3b’T3b’

T3bT3b


What is Slip ? What is Slip ? To produce torque in an induction motor, current To produce torque in an induction motor, current must flow in the rotor. must flow in the rotor. To induce current flow in the rotor, the rotor To induce current flow in the rotor, the rotor speed must be slightly slower than the speed must be slightly slower than the synchronous speed. synchronous speed. The difference between the synchronous speed The difference between the synchronous speed and the rotor speed (rated and the rotor speed (rated speed) is called the slip. speed) is called the slip.

StatorStator

FluxFlux

RotorRotorSlipSlip


Calculating Motor Rated SpeedCalculating Motor Rated SpeedFormula to find actual motor RPMFormula to find actual motor RPM

N =N =120 120 ff

PP( 1 - s )( 1 - s )

Where:Where:

N N - RPM of the motor- RPM of the motor

ff - Frequency in Hz- Frequency in Hz

PP - Number of poles of the motor- Number of poles of the motor

ss - (N- (Noo - N) / N - N) / Noo


Speed - Torque Curve Speed - Torque Curve (600%)(600%)

Locked Rotor Locked Rotor Torque (150%)Torque (150%)

Full Load Full Load Torque (100%)Torque (100%)

Pull Up Torque Pull Up Torque (125%)(125%)

Breakdown Breakdown Torque Torque (200-250%)(200-250%)

Rated SpeedRated Speed Synch SpeedSynch SpeedSPEEDSPEED

TORQUETORQUE CURRENTCURRENT

No Load No Load Current Current (30%)(30%)

SlipSlip

(300%)(300%)

(300%)(300%)

(200%)(200%)


Speed - Torque Curve Speed - Torque Curve

SPEEDSPEED

TORQUETORQUE


Typical NEMA Design CharacteristicsTypical NEMA Design Characteristics

00

100%100%

SPEEDSPEED

TO

RQ

UE

TO

RQ

UE 200%200%

300%300%

100%100%

NEMA Design ANEMA Design A

High breakdown torqueHigh breakdown torque

Normal starting torqueNormal starting torque

High starting currentHigh starting current

Low full load slipLow full load slip

Used in applications Used in applications that require: that require:

Occasional overloadsOccasional overloads

Better efficiencyBetter efficiency



00

100%100%

SPEEDSPEED

TO

RQ

UE

TO

RQ

UE 200%200%

300%300%

100%100%

Design B

NEMA Design BNEMA Design B

Normal breakdown torqueNormal breakdown torque

Normal starting torqueNormal starting torque

Low starting currentLow starting current

Normal full load slipNormal full load slip

less than 5%less than 5%

General Purpose Motor General Purpose Motor

Design A



00

100%100%

SPEEDSPEED

TO

RQ

UE

TO

RQ

UE 200%200%

300%300%

100%100%

Design CNEMA Design CNEMA Design C

Low breakdown torqueLow breakdown torque

High starting torqueHigh starting torque

Low starting currentLow starting current

Normal full load slipNormal full load slip

less than 5%less than 5%

Used in applications Used in applications that that require:require:

high breakaway torquehigh breakaway torque

Design A

Design B



00

100%100%

SPEEDSPEED

TO

RQ

UE

TO

RQ

UE 200%200%

300%300%

100%100%

Design DNEMA Design DNEMA Design D

High breakdown torqueHigh breakdown torque

High starting torqueHigh starting torque

Normal starting currentNormal starting current

High full load slipHigh full load slip

5 - 13%5 - 13%

Used in applications Used in applications that that require:require:

high breakaway torquehigh breakaway torque

Design C

Design A

Design B


Motor Nameplate DataMotor Nameplate Data


Understanding the NameplateUnderstanding the NameplateHP- HorsepowerHP- Horsepower

The horsepower The horsepower figure stamped on figure stamped on the nameplate is the nameplate is the the horsepower the horsepower the motor is rated motor is rated to to develop when develop when connected to a connected to a circuit circuit of the of the voltage, voltage, frequency and frequency and number of phases number of phases specified on the specified on the motor nameplate.motor nameplate.


Rotational Horsepower FormulaRotational Horsepower Formula

The horsepower formula in simplified formThe horsepower formula in simplified form

HP = HP = Torque x RPMTorque x RPM

52505250

Where:Where:

Torque - Amount of torque in lb.ft.Torque - Amount of torque in lb.ft.

RPM - RPM of the motorRPM - RPM of the motor

5250 - constant obtained by dividing 33,000 5250 - constant obtained by dividing 33,000 by 6.28 by 6.28

HP x 5250HP x 5250

RPMRPMTorque = Torque = OROR


Understanding the NameplateUnderstanding the Nameplate

RPM - Revolutions per MinuteRPM - Revolutions per Minute

The RPM value represents The RPM value represents the approximate speed at the approximate speed at which the motor will run when which the motor will run when properly connected and properly connected and delivering its rated outputdelivering its rated output



Poles Synchronous RPM Typical Nameplate RPM2 3600 34504 1800 17256 1200 11408 900 850



VoltageVoltage

The rated voltage The rated voltage figure on the motor figure on the motor nameplate refers to nameplate refers to the the voltage of the voltage of the supply supply circuit to circuit to which the which the motor motor should be should be connected, connected, to produce to produce rated rated horsepower and horsepower and RPM. RPM.

Key piece of information when selecting an inverter.


Effects of Voltage Variation Effects of Voltage Variation on the Motor at 60Hzon the Motor at 60Hz

Low VoltageLow Voltage Higher than normal currentHigher than normal current Higher than normal motor Higher than normal motor temperaturetemperature

High VoltageHigh Voltage Higher than normal currentHigher than normal current Lower than normal power Lower than normal power factor factor



PhasePhase

The phase figure on The phase figure on the the motor nameplate motor nameplate describes the describes the alternating current alternating current system that system that the motor the motor has been designed for. has been designed for.




Hz-FrequencyHz-Frequency

The frequency figure The frequency figure on the motor on the motor nameplate nameplate describes describes the the alternating alternating current current system system frequency frequency that must that must be applied be applied to the to the motor to motor to achieve achieve rated rated speed and speed and horsepower.horsepower.



AmpsAmps

The amp figure on The amp figure on the motor the motor nameplate nameplate represents the represents the approximate current approximate current draw by the motor draw by the motor when developing when developing rated horsepower on rated horsepower on a circuit of the a circuit of the voltage and voltage and frequency specified frequency specified on the nameplate. on the nameplate.




NEMA DesignNEMA Design

The NEMA Design The NEMA Design rating specifies rating specifies the the speed torque speed torque curve curve that will be that will be produced produced by the by the motor.motor.



Insulation ClassInsulation Class

The insulation class The insulation class letter designates letter designates the the amount of amount of allowable allowable temperature rise temperature rise based on the based on the insulation system insulation system and the motor and the motor service factor.service factor.


Insulation Class InformationInsulation Class Information Most common insulation classes are class B and FMost common insulation classes are class B and F

Insulation Class Ambient Temp. Temp. Rise Total Temp.

A 40oC 65oC 105oC

B 40oC 90oC 130oC

F 40oC 115oC 155oC

H 40oC 140oC 180oC


Understanding the NameplateUnderstanding the NameplateS.F. - Service FactorS.F. - Service Factor

The number by which The number by which the horsepower rating is the horsepower rating is multiplied to determine multiplied to determine the maximum safe load the maximum safe load that a motor may be that a motor may be expected to carry expected to carry continuously continuously Example - a 10HP motor with a Example - a 10HP motor with a service factor of 1.15 will service factor of 1.15 will deliver 11.5 horsepower deliver 11.5 horsepower continuously without continuously without exceeding exceeding the allowable the allowable temperature rise temperature rise of its of its insulation classinsulation class



FrameFrame

The frame designation The frame designation refers to the physical refers to the physical size of the motor as size of the motor as well well as certain as certain construction features construction features such as the shaft and such as the shaft and mounting dimensions.mounting dimensions.


Types of Motor EnclosuresTypes of Motor Enclosures

Open Drip-proof (ODP)Open Drip-proof (ODP) Totally enclosed non-ventilated (TENV)Totally enclosed non-ventilated (TENV) Totally enclosed fan cooled (TEFC)Totally enclosed fan cooled (TEFC) Totally enclosed blower cooled (TEBC)Totally enclosed blower cooled (TEBC)



ODPODP Open drip-proofOpen drip-proof Ventilating openings Ventilating openings

permit passage of permit passage of external cooling air over external cooling air over and around the and around the windings of the motor. windings of the motor. Small degree of Small degree of protection against liquid protection against liquid or solid particles or solid particles entering the enclosure.entering the enclosure.



TENVTENV Totally enclosed Totally enclosed

non-ventilatednon-ventilated Totally enclosed Totally enclosed

enclosure with no enclosure with no means of external means of external cooling.cooling.



TEFCTEFC Totally enclosed Totally enclosed

fan-cooledfan-cooled Totally enclosed Totally enclosed

enclosure with enclosure with external cooling external cooling means, such as a means, such as a shaft connected fanshaft connected fan



TEBCTEBC Totally enclosed Totally enclosed

blower-cooledblower-cooled

Totally enclosed Totally enclosed enclosure with enclosure with external cooling external cooling means such as a means such as a separately controlled separately controlled motor/blowermotor/blower


TEFC Speed RangesTEFC Speed Ranges

Constant TorqueConstant Torque 4:14:1 (15-60 Hz)(15-60 Hz)

Constant TorqueConstant Torque 10:110:1 (6-60 Hz)(6-60 Hz)

Variable TorqueVariable Torque 1-60 Hz 1-60 Hz 2:1 (30-60 Hz) CT 2:1 (30-60 Hz) CT


TENV/TEBC Speed RangesTENV/TEBC Speed Ranges

Constant TorqueConstant Torque 0 to Base Speed0 to Base Speed100:1100:1 (0.6-60 (0.6-60

Hz)Hz)1000:11000:1 (0.06-60 (0.06-60

Hz)Hz)


Motor Retrofit SummaryMotor Retrofit Summary

RPMRPM VoltsVolts PhasePhase AmpsAmps NEMA DesignNEMA Design Frame + any prefix Frame + any prefix

or suffix letter codesor suffix letter codes

LocationLocation Mounting OrientationMounting Orientation ApplicationApplication Enclosure StyleEnclosure Style Motor Control MethodMotor Control Method

Inverter-Duty?Inverter-Duty?


Motor Basics ExerciseMotor Basics Exercise Answer the following questions using your knowledge and/or the documents from this class.

1.) Write down the formula to calculate synchronous motor speed (please use the simplified form).

2.) To calculate the actual motor speed what has to be included in the above formula ?

3.) The majority of electric motors used in general purpose applications in industry today are what NEMA design ?

4.) A NEMA design D motor is characterized by very high breakdown torque, and a large percentage of slip ? (True or False)

5.) Name the two pieces of information needed off the motor nameplate when selecting an inverter.


Motor Basics ExerciseMotor Basics Exercise Answer the following questions using your knowledge and/or the documents from this class.

1.) Write down the formula to calculate synchronous motor speed (please use the simplified form).

Voltage and Full Load Amps (FLA)

120 x f / P

slip (120 x f / P) - slip

NEMA design B

True

2.) To calculate the actual motor speed what has to be included in the above formula?

3.) The majority of electric motors used in general purpose applications in industry today are what NEMA design?

4.) A NEMA design D motor is characterized by very high breakdown torque, and a large percentage of slip ? (True or False)

5.) Name two key pieces of information needed off the motor nameplate when selecting an inverter.


Yaskawa Electric America Yaskawa Electric America Technical Training Technical Training Services Services

09/06/200109/06/2001


Yaskawa Electric America Technical Training ServicesYaskawa Electric America Technical Training Services

For training information, please:For training information, please:

Call us at 1-800-YASKAWA and select option #6Call us at 1-800-YASKAWA and select option #6

Check out our website at Check out our website at www.yaskawa.com

E-mail us at [email protected] us at [email protected]

http://www.yaskawa.com/



07/08/2002 PP.AFD.02.MotorBasics 1 of 55 Yaskawa Electric America Motor Basics.

Documents

motor n s n n s s t1t3t2

motor n n s s s n t1t3t2

motor s n o n n o slide

n rpm

current n low

load slip n

actual motor rpm n

motor slide