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I.E.E.E. Industry Applications SocietySeminar on 3 Phase Motor Starting -- 2004.02.21
I.E.E.E. -- I.A.S.Motor Starting Seminar
By: James S. Nasby, Director of EngineeringMaster Contr ol Systems, Inc. (mastercontrols.com)
Seminar Details & Background
Background (History of Seminar)National Fir e Pr otection Association (NFPA)
Pumps for Fire Protection Systems
NEMA Standar d MG-1Motors and Generator s
See Also: Section VIII .References Cited
Topics to be Covered
I. Induction Motors General
II. Electrical Power Supply
III. Induction Motor Parameters
IV. 3 Motor Starting Types (8+ 1)
V. 3 Motor Running Types (3)
VI. Common Motor Wiring Types (14)
VII. Installation Considerations
VIII. References Cited
I. Motors GeneralMotor Types
Induction Motors
Three Phase
Non-Salient Pole Motors:
Usually Squirrel Cage Rotor Motors -but-
can be Wound Rotor (Slip Ring)
Induction Motors
Usually Squirr el Cage
Design Type: Usually NEMA Design BNormal Starting Torque
Normal Starting Current (KVA) Synchronous Motors Not Covered
I. Induction MotorsGeneral Definitions
Motor Poles Even Numbers (2, 4, 6, etc.)
Synchronous Speed (No Load Speed - Slip)
Starting Region Fixed Impedance
Running Region Energy Converter
Torques:Stall = Locked = Zero Speed Torque
Pull-up Torqu e
Breakdown Torque
Rated Torque
Starting Amps, KVA & Locked Rotor Code
Motor Starting Region contdMotor Torque Curve
Motor Torque and Pump Torque Curves
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I.E.E.E. Industry Applications SocietySeminar on 3 Phase Motor Starting -- 2004.02.21
II. Electr ical Power SuppliesPower Sources - Mains
Types of Power Source Three Phase A.C.
Power Source Characteristics
(Parameters)
Voltage (Utilization Voltage) -at-
Low voltage or Medium Voltage
Frequency 50 Hz or 60 Hz
Starting Voltage Drop -vs- Starter
Runn ing Voltage Drop -vs- Motor
Power Supply Characteristics contd- Power Quality -
Source Capacity - Weak or Stiff Source Starting Voltage Drop (15% of Controller Rated) Running Voltage Drop (5% of Motor Ra ted)
Method of Calculating - NEMA ICS-14
Gen-Sets - Frequency & Voltage
Voltage Balance (Amount of Imbalance)Small Voltage "Unbalnace" = Lar ge CurrentImbalance. (See NEMA MG-1, par t 1-14.36)
Voltage Har monics (Heats Windings)
Power Factors - Affected by Motor
III. Induction Motor Parameters
General Motor Cha racteristics
Induction Motor Types
Wound Rotor Motor
(Slip Ring Motor )
= Rotary Transformer
Squirr el Cage Motor = Ditto
But with Slip Rings Shorted
Frequency 50 Hz -vs- 60 Hz
NEMA Design Type B (MG-1)
NEMA Design Types
StandardThree Phase
InductionMotors are
NEMADesign B
( Rated Full Load Torque)
Rated || Speed (RPM)
Induction Motors - contdMotor Parameters - Electrical
Locked Rotor Code (KVA per Hp)
Service Factors
Usually 1.15 Maximum Allowed
Often Higher for Smaller Motors
Usually 1.0 Max. when used with VFD's
Service Factor (S.F.) -vs- Ideal Conditions
Max. Temperatur e (40 C Max.) -and-
Max. Altitude (3,300 ft /1,000 m Max.) -and-
Max. Voltage Imbalance (1% Max.)
Motor Parameters contdAbbreviations & Acronyms
Motor Currents FLA = Motor Full Load Amperes
FLC = Motor Full Load Current = FLA
LRC = LRA = Locked Rotor Current (Amps)
SFA = Service Factor Amps
Locked Rotor Code* Codes F & G Common
*May be Much Higher for Smaller Motors
and for Energy Efficient Motors
Power Factor (PF) Real -vs- ImaginaryStarting PF = 30% / 40% Typically
Running PF = 80% down to 8.0% from
Full Load to No Load, Typically
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I.E.E.E. Industry Applications SocietySeminar on 3 Phase Motor Starting -- 2004.02.21
Motor Parameters contdMotor Current Curve
Motor Current -vs- RPM Curves
Rated Running Current = 100%
Induction Motor Locked Rotor Codes
Table M-02 -- Motor Locked Rotor Code KVA Data and Allowed Horsepowers
"F" "G" "H" "J"Code Letter
Min. Max. Min. Max. Min. Max. Min. Max.
KVA per Hp 5.00 5.59 5.60 6.29 6.30 7.09 7.10 7.99LRA/FLA 482% 540% 540% 608% 608% 685% 685% 772%Allowed Hp 15 Hp and up 15 Hp and up 5 thru 10 Hp 5 Hp only
Note: The LRA/FLA ratios shown are approximate for illustration only.
Table M-03 -- Maximum Motor Locked Rotor Currents
Motor Voltage - 60 Hz valuesRated
HorsepowerCode
Letters 200 Vac 208 Vac 230 Vac 460 Vac 575 Vac
5 F - J 106 102 92 46 377.5 F - H 147 142 128 64 5110 F - H 186 179 162 81 6515 F - G 267 257 232 116 9320 F - G 334 321 290 145 11625 F - G 421 405 366 183 14630 F - G 499 480 434 217 17440 F - G 667 641 580 290 23250 F - G 833 801 724 362 29060 F - G 1,001 962 870 435 34875 F - G 1,249 1,201 1,086 543 434
100 F - G 1,668 1,603 1,450 725 580125 F - G 2,088 2,008 1,816 908 726150 F - G 2,496 2,400 2,170 1,085 868200 F - G 3,335 3,207 2,900 1,450 1,160250 F - G 4,198 4,036 3,650 1,825 1,460300 F - G 5,060 4,865 4,400 2,200 1,760350 F - G 5,865 5,639 5,100 2,550 2,040400 F - G 6,670 6,413 5,800 2,900 2,320450 F - G 7,475 7,188 6,500 3,250 2,600500 F - G 8,338 8,017 7,250 3,625 2,900
Note: The 460 Vac LRA values are from NFPA 20 Table 6-5.1.1. Others are calculated usingvoltage proportion.
Induction Motor Locked Rotor CurrentsMotor Parameters contd
Motor Stalled (Locked Rotor)Power Factor = Approx 40%
Motor Parameters contdMotor Theory and Formulae
Pur pose Electrical to Mechanical
Ener gy Conversion
Motor Star ting Region (Rotary Solenoid)
Running Region (Ener gy Converter )
Motor Torque & Motor Current Draw
-vs- Speed Curves
A-T-L-Starting
(Basic Motor Char acteristics)
Power Factor & Phase Angles
Efficiencies
Motor Starting -vs-Motor Running Regions
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I.E.E.E. Industry Applications SocietySeminar on 3 Phase Motor Starting -- 2004.02.21
Motor Starting -vs-Motor Running Regions
MotoringRegionStarting Region
Motor Parameters contdMotor Torque Curve
Motor Torque and Pump Torque Curves
Motor Parameters contdMotor Torque Curve
Motor Torque and Pump Torque Curves
Motor Parameters contdMotor Current Curve
Motor Curr ent -vs- RPM Curves
Rated Running Current = 100%
Motor Parameters contdMotor Current Curve
Motor Current -vs- RPM Curves
Rated Running Current = 100%
MotoringRegionStarting Region
Motor Theory and FormulaeMotor Starting Region
For a Motor at Stall, Motor Impedance isConstant. So:
I = E / Z (Ohms Law)
Current is Directly Proportional toMotor Voltage. I.E.:
Motor Current = Voltage / Impedance
Power Factor (P.F.) is Typically 30% to40% at Stall (and for most of thestarting region)
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I.E.E.E. Industry Applications SocietySeminar on 3 Phase Motor Starting -- 2004.02.21
Motor Theory and FormulaeMotor Star ting Region contd
In the Starting (Accelerating) Region:Torque is Proportional to the Square of
the Applied Motor Voltage
T = K1 x V2 -or- Since Current isproportional to Voltage (see above):
T = K2 x I2
Thus: Torque is also Proportional to theSquare of the Motor Current
Motor Theory and FormulaeMotor Star ting Region contd
Example of Starting Torque Proportional tothe Square of Applied Motor Voltage.
E.G. 57% Volts = 33% Rated Stall Torque.
Motor Theory and FormulaeMotor Running Region
Motor Running Region (Energy Converter):
Mechanical Power is Torque x Speed:
Pm = K3 x Tq x RPM
Motor Torque is Whatever the Load Requires
Electrical Power Input is:
Pe = Pm + Motor Losses = Pm / Efficiency
But, Electrical Power Input is also given as:
Pe = K4 x V x Ireal (Volts x Real Current)
So: Ireal = K5 x Pe / Volts
Thus Motor Current is Inversely Proportionalto Motor Voltage with a Running Motor
Motor Running -vs-Motor Starting Regions
Rated Torque (100%) times Rated Speed (E.g.1750 RPM) yields Motor Rated Hor sepower.
IV. Motor Starting
General - Overview Types of Reduction
Voltage Reduction: WyeDelta, Soft Start, a ndAutotransformer
Curr ent Reduction: Primar y Impedance (Primar yResistor, Primary or Neutral Reactor)
Motor Impedance (Wound Rotor)
Two Specialty Types
Medium Voltage Four C ommon Types: A-T-L,Primary Reactor, Neutral Reactor -and-Autotransformer
Low Voltage - Wound Rotor (Not U.L. Listed)
Motor Starting - contdEight (+1) Common Low Voltage Starting Types:
Across-the-Line (A-T-L or Direct-On-Line)
Part Winding (Half Winding) Start
Primary Resistor Start
Primary (or Neutral) Reactor Start
Wye-Delta (Star-Delta) - Open Transition
Wye-Delta (Star-Delta) - Closed Transition
Soft Start / Soft Stop (SCR Phase Modulation)
Autotransformer
VFD Ramp-up (and Ramp-down on some)
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I.E.E.E. Industry Applications SocietySeminar on 3 Phase Motor Starting -- 2004.02.21
Motor Starting contdAcross-the-Line (Direct On Line)
Motor Starting contdAcross-the-Line (Direct On Line)
Motor Starting contdPart Winding Start
Note: The Motor Must be WoundSpecifically for Part Winding Starting.
Motor Starting contdPart Winding Start
Motor Starting contdPrimary Resistor Start
Motor Starting contdPrimary Resistor Start
Note: 65% Resistor Impedance is
1.24 -0.40 = 0.84 pu
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I.E.E.E. Industry Applications SocietySeminar on 3 Phase Motor Starting -- 2004.02.21
Motor Starting contdPrimary Reactor Start
Motor Starting contdPrimary (or Neutral) Reactor Start
Note: 65% Reactor Impedance is
1.54 1.00 = 0.54 pu
Motor Starting Torque Comparison
Curves B, C & D are at 65% Motor Starting Voltage(Reference Source Credit on Next Slide)
00
Motor Torque Comparison contdA=ATL, B=A.T., C=Pri. Res., D=Reactor
Gerhart W. Heumann (G.E.), MagneticControls of Industrial Motors, Wiley & Sons.
Motor Starting contdPrimary (or Neutral) Reactor Start
Motor Starting contdWye-Delta Open Transition
LPM Module = Leading Phase Monitor
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I.E.E.E. Industry Applications SocietySeminar on 3 Phase Motor Starting -- 2004.02.21
Motor Starting contdWye-Delta Open Transition
Motor Starting contdWye-Delta Open Transition
Motor Starting contdWye-Delta Open Transition
Motor Starting contdWye-Delta Transition Hazard
Closed
Leading
Lagging
Motor Starting contdWye-Delta Closed Transition
Motor Starting contdWye-Delta (Open or Closed Xtn.)
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I.E.E.E. Industry Applications SocietySeminar on 3 Phase Motor Starting -- 2004.02.21
Motor Starting - contdSoft (Solid State - SCR) Start
Motor Starting - contdSoft (Solid State - SCR) Start
Motor Starting - contdAutotransformer Start
Motor Starting - contdAutotransformer Start
Motor Starting CharacteristicsParameter Chart
Fire Pump Starting Type Characteristics- for -
Electric Fire Pump Motors and Controllers
Starting Chara cteristics (at Stall) -- Typical Values -for- Fully Load Pump (1)
Starting Starting Starting AccelerateMotor Motor Amps Amps Starting Power Starting Full LoadType Contactors Closed & KVA & KVA Power % F.L. Torque to
Starting Type Note Note (3) Transition % LRA % FLA Factor Note (4) % ATL Full Speed Notes
Across-the-Line Any 1 N/A 100% 600% 40% 240% 100% Yes (a)
Part Winding Special (2) 2 Yes 65 390 40 156 48 Usually (b)Primar y Resistor Any 2 Yes 65 390 80 314 42 Yes (c)
Primar y Reactor Any 2 Yes 65 390 28 111 42 Yes (c)
Neutral Reactor 6/12 Lead 2 Yes 65 390 28 111 42 Yes (c)
Wye-Delta Open 6/12 Lead 3 No 33/100 200/600 40 80/240 33 No (d)Wye-Delta Closed 6/12 Lead 4 Yes 33/100 200/600 40 80/240 33 No (d)(e)
Soft Start/Stop Any 1/2 Yes 40/67 240/400 Varies Ramps 16/44 Yes (f)
Autotransformer Any 3 Yes 46 276 40 110 42 Yes (c)(g)
Motor Starting CharacteristicsParameter Notes to Chart
Motor Starting Characteristics Chart
Notes(1) Refer to Factory details.
(2) Part Winding Motors must be wound specifically for this service. Some motors may notaccelerate to full speed in the starting mode. See Note (b).
(3) Units with two or more contactors have two basic steps (Accelerate & Run) with steps threeand four being for transitions.
(4) Starting KW Power as a percent of motor full load power requirement.
(a) Also called "A-T-L" or Direct-On-Line. Motor Power Factor taken as 40%. Other values
shown are due to the effects of the controller.(b) Part Winding Parameters vary with the motor. Starting Amps & KVA vary from around
60% to 70%, Starting Torque from around 45% to 50%. The motor can start a fully loadedpump if it has no large torque dip or cusp. See the text discussion on Part Winding Startingfor details.
(c) Figures are for tap set at 65% which yields a motor voltage of 65% of line (mains) voltage.(d) The Dual Figures are for Starting and Transition. The transition values are to finish
accelerating a fully loaded pump. Examples include deluge or open systems, re-starting afully loaded pump after a power failure or interruption, and failure of another pump feeding
the same system.(e) Ignores the momentary transition resistor loads.
(f) Varies with pump load and particular Soft Starter used. Values shown are initial andmaximum for a typical fully loaded pump. MCS uses the second (Start) contactor for
isolation. Others use only the Bypass contactor.(g) The 46% Starting Amps & KVA figures include the Autotransformer exciting current.
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I.E.E.E. Industry Applications SocietySeminar on 3 Phase Motor Starting -- 2004.02.21
V. Motor Running Types
Constant Speed Running Full Voltage Running
- Synchronous Speeds (3,600 RPM & etc.)
- Slip Frequencies - Running (Rated) Speeds
Motor Lead Wire Running Currents
- Three Lead = Full Motor Current
- Six Lead Parallel Run (Part Winding Start)
= 50% of FLC per set
- Six Lead (Wye-Delta Start)
= 58% (57.7%) of FLC per set
Motor Running - contd
Variable Speed Running Wound Rotor Control
- Changes Motor Secondary Impedance -and-
- Motor Torque Curve
Variable Frequency - Variable SpeedContr ol (VFDs)
- Changes Motor Torque and Current Curves
- Changes Motor Synchronous Speed and-
- Changes Motor Running (Loaded) Speed
Wound Rotor Speed-Torque Curves(Reference Source Credit on Next Slide)
Wound Rotor Speed-Torque Curves- Flipped and Rotated -
Gerhart W. Heumann (G.E.), MagneticControls of Industrial Motors, Wiley & Sons.
VI. Motor Wiring Motor LeadConfigurat ions (Fourteen)
Three Lead Three Coil
(Single Voltage) (T1-T3)
Six Lead Thr ee Coil
Wye Runing (T1-T3 & T4-T6) Delta Running (T1-T3 & T4-T6)
Par allel Run (Six Lead - Six Coil)
T1-T3 and T7-T8 - or -
Both Sets Labeled T1-T3
Motor Lead Configurations3 Lead 3 Coil - Wye Running
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I.E.E.E. Industry Applications SocietySeminar on 3 Phase Motor Starting -- 2004.02.21
Motor Lead Configurat ions3 Lead 3 Coil - Delta Running
Motor Lead Configurations6 Lead - 3 Coil - Wye Running
Motor Lead Configurat ions6 Lead 3 Coil - Delta Running
6 Lead 6 Coil - Wye RunningParallel Running
6 Lead - 6Coil - Delta RunningParallel Running Motor Wir ing contd
Nine Lead (Dual Voltage) (T1-T9)
Wye Wound
Delta Wound
Suitable for Par t Winding Start ?
Twelve Lead (T1-T12)
Dual Voltage
Single Voltage (Para llel Run )
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9 Lead - 6 Coil - Wye RunningSeries Running
9 Lead - 6 Coil - Wye RunningParallel Running
9 Lead - 6 Coil - Delta RunningSeries Running
9 Lead - 6 Coil - Delta RunningParallel Running
12 Lead - 6 Coil - Wye RunningSeries Running
12 Lead - 6 Coil - Wye RunningParallel Running
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I.E.E.E. Industry Applications SocietySeminar on 3 Phase Motor Starting -- 2004.02.21
12 Lead - 6 Coil - Delta RunningSeries Running
12 Lead - 6 Coil - Delta RunningParallel Running
Typical 12 Lead Motor Wiring Diagram
Courtesy of Marathon Electric
VII. Induction Motors --Installation Considerations
Physical
Location - Ideally Within Site of Controller
Motor Protection: Fire, Security, Other Hazards
Access All Sides & Condu it Access
Electrical N.E.C. (NFPA 70) - 430 (& 695)
Conduit & Hubs
Environmental
Conductor Sizing Incoming & Motor Cir cuit
Voltage Drops: Start & R un
Cable Impedances and Run Lengths(See NEMA ICS-14)
Motor Installation contdStart-up (Commissioning)
Current Measurements
Voltage Measurements
Estimating Motor Load
- FLA -vs- Voltage
- SFA (115%) - Max. AllowedUnder Any Conditions(Temperature, Altitude, VoltageImbalance) on ANY Phase
Starting Methods -vs- Motor Types
Table M-04 - Mot or and Start ing Types
Starting Type Motor Type Starting Type Motor Type
Full voltage Standard/Any Primary Reactor Standard/Any
Part Winding Part Winding Primary Resistor Standard/Any
Wye Delta - Closed Delta Run Autotransformer Standard/Any
Wye Delta - Open Delta Run Soft Start (SCR) Standard/Any
Neutral Reactor Wye Running Wound Rotor Wound rotor
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Motor Types -vs- Starting Types
Motor Description(a)
Starting Method(b)
Run Type Number of Leads PartWinding
Wye (Star)Delta
(c)
NeutralReactor
"Other 5" Figure
W ye R un T hr ee L ea d N o N o N o Y es 7- 4
Delta Run Three Lead No No No Yes 7-5
Wye Run Six Lead, Single Coil No No Yes Yes 7-6
Delta Run Six Lead, Single Coil No Yes No Yes 7-7
Wye Run Six Lead Parallel Some(d)
No No Yes 7-8
D el ta Run S ix Lead P ar al lel S om e(d)
No No Yes 7-9
Wye Run Nine Lead Ser ies No No Ye s Ye s 7-10
Wye Run Nine Lead Parallel Some(d) No No Yes 7-11
De lt a R un N ine L ea d Ser ie s N o N o N o Ye s 7- 12
D el ta Run N in e Lead P ar al lel N o(e)
No No Yes 7-13
Wye Run Twelve Lead Seri es No No Ye s Ye s 7-14
Wye Run Twelve Lead Parallel Some(d) No Yes Yes 7-15
De lt a R un T we lve L ea d Se ri es N o Y es N o Ye s 7- 16
Delta Run Twelve Lead Parallel Some(d)
Yes No Yes 7-17
Notes:(a) The Motor "Type" (Wye or Delta) is theRunning configuration, regardless of how the motor is started.
Wound Rotor Motors are not covered in this chart.(b) "Other 5" are: Full voltage (A-T-L), Primary Resistor, Primary Reactor, Soft Start and Autotransformer.(c) Either Open or Closed Transition Wye-Delta (Star-Delta).(d) "Some" = May be usedonly of the motor is labeled as suitable for Part Winding Starting.(e) The 9 lead "Double Delta" method has unequal currents and is not suitable for standard Part Winding controllers.
Table M-06 -- Motor SuitabilityMotor Types -vs-Starting Types VIII. References Cited
A. National Fire Protection Association (NFPA)
Kenneth I. I sman, Milosh T. Puchovsky,
"Pump for Fire Protection Systems"
B. NEMA Standard MG-1,
"Motors and Generators"
C. NEMA ICS-14,
"Application Guide for Fire PumpControllers"
D. Institute of Electrical and Electronic Engineers(I.E.E.E.) numerous papers on motors.
Pumps for Fire Protection Systems-by- Ken Isman & Milosh Puchovsky
- with -
Chapters on
- PowerSources
- Motors,
- and -
- Controllers
by Jim Nasby
NEMA Standard MG-1Motors and Generators
NEMA ICS-14Fire Pump Controller Application Guide Thank You !!
The Chicago Chgapter of the I.E.E.E.
Industrial Applications Society
-- and from --
Jim Nasby, Mastercontrols.com