I.E.E.E. Industry Applications Society
Seminar on 3 Phase Motor Starting -- 2004.02.21
I.E.E.E. -- I.A.S.
Motor Starting Seminar
Seminar Details & Background
♦
Background (History of Seminar)
National Fire Protection Association (NFPA)
“Pumps for Fire Protection Systems”
♦
NEMA Standard MG-1
Motors and Generators
♦
See Also: Section VIII.
References Cited
By: James S. Nasby, Director of Engineering
Master Control Systems, Inc. (mastercontrols.com)
I. Motors – General
Motor Types
Topics to be Covered
I.
II.
III.
IV.
V.
VI.
VII.
VIII.
Induction Motors – General
Electrical Power Supply
Induction Motor Parameters
3Ø Motor Starting Types (8+1)
3Ø Motor Running Types (3)
Common Motor Wiring Types (14)
Installation Considerations
References Cited
♦
♦
♦
♦
♦
Normal Starting Torque
Normal Starting Current (KVA)
♦
I. Induction Motors
♦
♦
♦
♦
♦
Synchronous Motors Not Covered
Motor Starting Region – cont’d
Motor Torque Curve
General Definitions
♦
Induction Motors
Three Phase
Non-Salient Pole Motors:
Usually Squirrel Cage Rotor Motors -butcan be Wound Rotor (Slip Ring)
Induction Motors
Usually Squirrel Cage
Design Type: Usually NEMA Design “B”
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 Torque
Breakdown Torque
Rated Torque
Starting Amps, KVA & Locked Rotor Code
Motor Torque and Pump Torque Curves
Page 1
I.E.E.E. Industry Applications Society
Seminar on 3 Phase Motor Starting -- 2004.02.21
II. Electrical Power Supplies
Power Supply Characteristics – cont’d
- Power Quality -
Power Sources - Mains
♦
♦
Types of Power Source
♦
Power Source Characteristics
(Parameters)
–
–
–
–
–
Source Capacity - Weak or Stiff Source
– Starting Voltage Drop (15% of Controller Rated)
– Running Voltage Drop (5% of Motor Rated)
– Method of Calculating - NEMA ICS-14
– Gen-Sets - Frequency & Voltage
– Three Phase A.C.
♦
Voltage (Utilization Voltage) -atLow voltage or Medium Voltage
Frequency – 50 Hz or 60 Hz
Starting Voltage Drop -vs- Starter
Running Voltage Drop -vs- Motor
Voltage Balance (Amount of Imbalance)
Small Voltage "Unbalnace" = Large Current
Imbalance. (See NEMA MG-1, part 1-14.36)
♦
Voltage Harmonics (Heats Windings)
♦
Power Factors - Affected by Motor
NEMA Design Types
III. Induction Motor Parameters
General Motor Characteristics
♦ Induction Motor Types
– Wound Rotor Motor
(Slip Ring Motor)
= Rotary Transformer
– Squirrel Cage Motor = Ditto
– But with Slip Rings Shorted
♦
♦
( Rated Full Load Torque)
Frequency – 50 Hz -vs- 60 Hz
NEMA Design Type “B” (MG-1)
Rated | Speed (RPM)
Induction Motors
Motor Parameters – cont’d
Locked Rotor Code (KVA per Hp)
Service Factors
♦
- cont’d
Motor Parameters - Electrical
♦
♦
Abbreviations & Acronyms
Motor Currents
–
–
–
–
–
– Usually 1.15 Maximum Allowed
– Often Higher for Smaller Motors
– Usually 1.0 Max. when used with VFD's
♦
Standard
Three Phase
Induction
Motors are
NEMA
Design “B”
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- Imaginary
Service Factor (S.F.) -vs- Ideal Conditions
– Max. Temperature (40 °C Max.) -and– Max. Altitude (3,300 ft /1,000 m Max.) -and– Max. Voltage Imbalance (1% Max.)
Starting 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 Society
Seminar on 3 Phase Motor Starting -- 2004.02.21
Motor Parameters – cont’d
Induction Motor Locked Rotor Codes
Motor Current Curve
Table M-02 -- Motor Locked Rotor Code KVA Data and Allowed Horsepowers
Code Letter
KVA per Hp
LRA/FLA
Allowed Hp
Rated Running Current = 100%
"F"
Min.
Max.
5.00
5.59
482% 540%
15 Hp and up
"G"
Min.
"H"
Max. Min.
5.60
6.29
540% 608%
15 Hp and up
"J"
Max. Min.
6.30
7.09
608% 685%
5 thru 10 Hp
Note: The LRA/FLA ratios shown are approximate for illustration only.
Motor Current -vs- RPM Curves
Motor Parameters – cont’d
Induction Motor Locked Rotor Currents
Motor Stalled (Locked Rotor)
Power Factor = Approx 40%
Table M-03 -- Maximum Motor Locked Rotor Currents
Rated
Horsepower
5
7.5
10
15
20
25
30
40
50
60
75
100
125
150
200
250
300
350
400
450
500
Code
Letters
F-J
F-H
F-H
F-G
F-G
F-G
F-G
F-G
F-G
F-G
F-G
F-G
F-G
F-G
F-G
F-G
F-G
F-G
F-G
F-G
F-G
Motor Voltage - 60 Hz values
200 Vac
208 Vac
230 Vac
460 Vac
575 Vac
106
147
186
267
334
421
499
667
833
1,001
1,249
1,668
2,088
2,496
3,335
4,198
5,060
5,865
6,670
7,475
8,338
102
142
179
257
321
405
480
641
801
962
1,201
1,603
2,008
2,400
3,207
4,036
4,865
5,639
6,413
7,188
8,017
92
128
162
232
290
366
434
580
724
870
1,086
1,450
1,816
2,170
2,900
3,650
4,400
5,100
5,800
6,500
7,250
46
64
81
116
145
183
217
290
362
435
543
725
908
1,085
1,450
1,825
2,200
2,550
2,900
3,250
3,625
37
51
65
93
116
146
174
232
290
348
434
580
726
868
1,160
1,460
1,760
2,040
2,320
2,600
2,900
Note: The 460 Vac LRA values are from NFPA 20 Table 6-5.1.1. Others are calculated using
voltage proportion.
Motor Starting -vsMotor Running Regions
Motor Parameters – cont’d
Motor Theory and Formulae
♦
♦
Purpose – Electrical to Mechanical
Energy Conversion
– Motor Starting Region (Rotary Solenoid)
– Running Region (Energy Converter)
♦
♦
Motor Torque & Motor Current Draw
-vs- Speed Curves
A-T-L-Starting
(Basic Motor Characteristics)
– Power Factor & Phase Angles
– Efficiencies
Page 3
Max.
7.10
7.99
685% 772%
5 Hp only
I.E.E.E. Industry Applications Society
Seminar on 3 Phase Motor Starting -- 2004.02.21
Motor Parameters – cont’d
Motor Starting -vsMotor Running Regions
Starting Region
Motor Torque Curve
Motoring
Region
Motor Torque and Pump Torque Curves
Motor Parameters – cont’d
Motor Parameters – cont’d
Motor Torque Curve
Motor Current Curve
Rated Running Current = 100%
Motor Current -vs- RPM Curves
Motor Torque and Pump Torque Curves
Motor Theory and Formulae
Motor Starting Region
Motor Parameters – cont’d
Motor Current Curve
Starting Region
Motoring
Region
For a Motor at Stall, Motor Impedance is
Constant. So:
I = E / Z (Ohm’s Law)
Current is Directly Proportional to
Motor Voltage. I.E.:
Motor Current = Voltage / Impedance
Power Factor (P.F.) is Typically 30% to
40% at Stall (and for most of the
starting region)
Rated Running Current = 100%
Motor Current -vs- RPM Curves
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I.E.E.E. Industry Applications Society
Seminar on 3 Phase Motor Starting -- 2004.02.21
Motor Theory and Formulae
Motor Theory and Formulae
Motor Starting Region – cont’d
Motor Starting Region – cont’d
In the Starting (Accelerating) Region:
Torque is Proportional to the Square of
the Applied Motor Voltage
T = K1 x V2 -or- Since Current is
proportional to Voltage (see above):
T = K2 x I2
Thus: Torque is also Proportional to the
Square of the Motor Current
Example of Starting Torque Proportional to
the Square of Applied Motor Voltage.
E.G. 57% Volts = 33% Rated Stall Torque.
Motor Theory and Formulae
Motor Running Region
Motor Running -vsMotor Starting Regions
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 Proportional
to Motor Voltage with a Running Motor
Rated Torque (100%) times Rated Speed (E.g.
1750 RPM) yields Motor Rated Horsepower.
IV. Motor Starting
♦
Motor Starting
Eight (+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)
General - Overview – Types of Reduction
– Voltage Reduction: Wye–Delta, Soft Start, and
Autotransformer
– Current Reduction: Primary Impedance (Primary
Resistor, Primary or Neutral Reactor)
– Motor Impedance (Wound Rotor)
♦
- cont’d
Two Specialty Types
– Medium Voltage – Four Common Types: A-T-L,
Primary Reactor, Neutral Reactor -andAutotransformer
– Low Voltage - Wound Rotor (Not U.L. Listed)
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I.E.E.E. Industry Applications Society
Seminar on 3 Phase Motor Starting -- 2004.02.21
Motor Starting – cont’d
Motor Starting – cont’d
Across-the-Line (Direct On Line)
Across-the-Line (Direct On Line)
Motor Starting – cont’d
Motor Starting – cont’d
Part Winding Start
Part Winding Start
Note: The Motor Must be Wound
Specifically for Part Winding Starting.
Motor Starting – cont’d
Motor Starting – cont’d
Primary Resistor Start
Primary Resistor Start
Note: 65% Resistor Impedance is
1.24 - 0.40 = 0.84 pu
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I.E.E.E. Industry Applications Society
Seminar on 3 Phase Motor Starting -- 2004.02.21
Motor Starting – cont’d
Motor Starting – cont’d
Primary Reactor Start
Primary (or Neutral) Reactor Start
Note: 65% Reactor Impedance is
1.54 – 1.00 = 0.54 pu
Motor Torque Comparison – cont’d
Motor Starting Torque Comparison
A=ATL, B=A.T., C=Pri. Res., D=Reactor
“0”
“0”
Curves B, C & D are at 65% Motor Starting Voltage
(Reference Source Credit on Next Slide)
Gerhart W. Heumann (G.E.), “Magnetic
Controls of Industrial Motors”, Wiley & Sons.
Motor Starting – cont’d
Motor Starting – cont’d
Primary (or Neutral) Reactor Start
Wye-Delta Open Transition
LPM Module = Leading Phase Monitor®
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I.E.E.E. Industry Applications Society
Seminar on 3 Phase Motor Starting -- 2004.02.21
Motor Starting – cont’d
Motor Starting – cont’d
Wye-Delta Open Transition
Wye-Delta Open Transition
Motor Starting – cont’d
Motor Starting – cont’d
Wye-Delta Open Transition
Wye-Delta Transition Hazard
Lagging
Leading
Closed
Motor Starting – cont’d
Motor Starting – cont’d
Wye-Delta Closed Transition
Wye-Delta (Open or Closed Xtn.)
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I.E.E.E. Industry Applications Society
Seminar on 3 Phase Motor Starting -- 2004.02.21
Motor Starting - cont’d
Motor Starting - cont’d
Soft (Solid State - SCR) Start
Soft (Solid State - SCR) Start
Motor Starting - cont’d
Autotransformer Start
Motor Starting - cont’d
Autotransformer Start
Motor Starting Characteristics
Parameter Chart
Motor Starting Characteristics
Parameter Notes to Chart
Motor Starting Characteristics Chart
Fire Pump Starting Type Characteristics
- for Electric Fire Pump Motors and Controllers
Notes
(1) Refer to Factory details.
(2) Part Winding Motors must be wound specifically for this service. Some motors may not
accelerate 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 three
and 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 loaded
pump if it has no large torque dip or cusp. See the text discussion on Part Winding Starting
for 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 a
fully 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 and
maximum 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.
Starting Characteristics (at Stall) -- Typical Values -for- Fully Load Pump (1)
Starting Type
Across-the-Line
Motor
Type
Note
Any
Motor
Contactors Closed
Note (3) Transition
1
N/A
Starting
Amps
& KVA
% LRA
100%
Starting
Amps
& KVA
% FLA
600%
Starting
Power
Factor
40%
Starting
Power
% F.L.
Note (4)
240%
Starting
Torque
% ATL
100%
Accelerate
Full Load
to
Full Speed
Yes
Notes
(a)
(b)
(c)
Part Winding
Primary Resistor
Special (2)
Any
2
2
Yes
Yes
65
65
390
390
40
80
156
314
48
42
Usually
Yes
Primary Reactor
Neutral Reactor
Any
6/12 Lead
2
2
Yes
Yes
65
65
390
390
28
28
111
111
42
42
Yes
Yes
(c)
(c)
Wye-Delta Open
Wye-Delta Closed
6/12 Lead
6/12 Lead
3
4
No
Yes
33/100
33/100
200/600
200/600
40
40
80/240
80/240
33
33
No
No
(d)
(d)(e)
1/2
3
Yes
Yes
40/67
46
240/400
276
Varies
40
Ramps
110
16/44
42
Yes
Yes
(f)
(c)(g)
Soft Start/Stop
Autotransformer
Any
Any
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Seminar on 3 Phase Motor Starting -- 2004.02.21
V. Motor Running Types
Motor Running - cont’d
Constant Speed Running
♦ Full Voltage Running
Variable Speed Running
♦ Wound Rotor Control
- Synchronous Speeds (3,600 RPM & etc.)
- Slip Frequencies - Running (Rated) Speeds
♦
- Changes Motor Secondary Impedance -and- Motor Torque Curve
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
Variable Frequency - Variable Speed
Control (VFDs)
- Changes Motor Torque and Current Curves
- Changes Motor Synchronous Speed –and- Changes Motor Running (Loaded) Speed
Wound Rotor Speed-Torque Curves
- Flipped and Rotated -
Wound Rotor Speed-Torque Curves
(Reference Source Credit on Next Slide)
Gerhart W. Heumann (G.E.), “Magnetic
Controls of Industrial Motors”, Wiley & Sons.
VI. Motor Wiring – Motor Lead
Configurations (Fourteen)
♦
♦
Motor Lead Configurations
3 Lead – 3 Coil - Wye Running
Three Lead – Three Coil
(Single Voltage) (T1-T3)
Six Lead – Three Coil
– Wye Runing (T1-T3 & T4-T6)
– Delta Running (T1-T3 & T4-T6)
♦
Parallel Run (Six Lead - Six Coil)
– T1-T3 and T7-T8 - or – Both Sets Labeled T1-T3
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I.E.E.E. Industry Applications Society
Seminar on 3 Phase Motor Starting -- 2004.02.21
Motor Lead Configurations
3 Lead – 3 Coil - Delta Running
Motor Lead Configurations
6 Lead - 3 Coil - Wye Running
Motor Lead Configurations
6 Lead – 3 Coil - Delta Running
6 Lead – 6 Coil - Wye Running
Parallel Running
6 Lead - 6Coil - Delta Running
Parallel Running
Motor Wiring – cont’d
♦
Nine Lead (Dual Voltage) (T1-T9)
– Wye Wound
– Delta Wound
– Suitable for Part Winding Start ?
♦
Twelve Lead (T1-T12)
– Dual Voltage
– Single Voltage (Parallel Run)
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I.E.E.E. Industry Applications Society
Seminar on 3 Phase Motor Starting -- 2004.02.21
9 Lead - 6 Coil - Wye Running
Series Running
9 Lead - 6 Coil - Wye Running
Parallel Running
9 Lead - 6 Coil - Delta Running
Series Running
9 Lead - 6 Coil - Delta Running
Parallel Running
12 Lead - 6 Coil - Wye Running
Series Running
12 Lead - 6 Coil - Wye Running
Parallel Running
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I.E.E.E. Industry Applications Society
Seminar on 3 Phase Motor Starting -- 2004.02.21
12 Lead - 6 Coil - Delta Running
Series Running
12 Lead - 6 Coil - Delta Running
Parallel Running
Typical 12 Lead Motor Wiring Diagram
VII. Induction Motors -Installation Considerations
♦
Physical
– Location - Ideally Within Site of Controller
– Motor Protection: Fire, Security, Other Hazards
♦
♦
Access – All Sides & Conduit Access
Electrical N.E.C. (NFPA 70) - §430 (& § 695)
–
–
–
–
–
Courtesy of Marathon Electric
Motor Installation – cont’d
Starting Methods -vs- Motor Types
Start-up (Commissioning)
♦
♦
♦
Conduit & Hubs
Environmental
Conductor Sizing – Incoming & Motor Circuit
Voltage Drops: Start & Run
Cable Impedances and Run Lengths
(See NEMA ICS-14)
Current Measurements
Voltage Measurements
Estimating Motor Load
Table M-04 - Motor and Starting Types
Starting Type
- FLA -vs- Voltage
- SFA (115%) - Max. Allowed
Under Any Conditions
(Temperature, Altitude, Voltage
Imbalance) on ANY Phase
Page 13
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
I.E.E.E. Industry Applications Society
Seminar on 3 Phase Motor Starting -- 2004.02.21
Motor Types -vs- Starting Types
VIII. References Cited
Table M-06 -- Motor Suitability
Motor Types -vs- Starting Types
Motor Description
(a)
Run Type
Number of Leads
Part
Winding
Wye (Star)
Delta(c)
Neutral
Reactor
"Other 5"
Figure
Wye Run
Three Lead
No
No
No
Yes
7-4
Delta Run
Three Lead
No
No
No
Yes
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
Six Lead Parallel
Some(d)
No
No
Yes
7-9
Wye Run
Nine Lead Series
No
No
Yes
Yes
7-10
Wye Run
Nine Lead Parallel
Some(d)
No
No
Yes
7-11
Delta Run
Nine Lead Series
No
No
No
Yes
7-12
7-13
Nine Lead Parallel
No
(e)
"Pump for Fire Protection Systems"
7-5
Delta Run
Delta Run
A. National Fire Protection Association (NFPA)
Kenneth I. Isman, Milosh T. Puchovsky,
Starting Method(b)
B. NEMA Standard MG-1,
7-8
No
No
Yes
Wye Run
Twelve Lead Series
No
No
Yes
Yes
Wye Run
Twelve Lead Parallel
Some(d)
No
Yes
Yes
7-15
Delta Run
Twelve Lead Series
No
Yes
No
Yes
7-16
Delta Run
Twelve Lead Parallel
Some(d)
Yes
No
Yes
7-17
"Motors and Generators"
C. NEMA ICS-14,
"Application Guide for Fire Pump
Controllers"
7-14
Notes:
(a) The Motor "Type" (Wye or Delta) is the Running 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 used only 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.
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
NEMA Standard – MG-1
Motors and Generators
- with Chapters on
- Power
Sources
- Motors,
- and -
Controllers
by Jim Nasby
Thank You !!
NEMA ICS-14
Fire Pump Controller Application Guide
The Chicago Chgapter of the I.E.E.E.
Industrial Applications Society
-- and from --
Jim Nasby, Mastercontrols.com
Page 14