of 79
8/12/2019 1 Electrical Theory
1/79
(c)2005 Penrose
Electrical Theory
Howard W Penrose, Ph.D., CMRPInstructor
8/12/2019 1 Electrical Theory
2/79
(c)2005 Penrose
Overview of Electrical Theory
Atomic Structure and Electron Movement
Conductors, Semi-Conductors, Insulators Basic Electricity: Current, Voltage and
Resistance
Electrical and Magnetic Fields Alternating Current Electricity: L, C, X L, XC, Z
8/12/2019 1 Electrical Theory
3/79
(c)2005 Penrose
Atomic Structure andElectron Movement
8/12/2019 1 Electrical Theory
4/79
(c)2005 Penrose
Classic Atom
+ N -
8/12/2019 1 Electrical Theory
5/79
(c)2005 Penrose
Electron Movement
+ N -
Photon
Photon -
8/12/2019 1 Electrical Theory
6/79
(c)2005 Penrose
Conductors, Semi-Conductors and
Insulators
8/12/2019 1 Electrical Theory
7/79
(c)2005 Penrose
Conductors
Free Electrons (e) Easily Directed Usually metals
Copper Aluminum
Gold Platinum
-
-
-
-
-
--
--
-
-
-
-
-
-
--
-
-
-
--
- -
-
-
--
-
-
- +
8/12/2019 1 Electrical Theory
8/79
(c)2005 Penrose
Semi-Conductors
Dielectrics
4 Valence Electrons Polarize with Some
Electron Flow due toElectrical Fields
+
-
8/12/2019 1 Electrical Theory
9/79
(c)2005 Penrose
Insulators
No Free Electrons
No Current Flow withField
+
-
8/12/2019 1 Electrical Theory
10/79
(c)2005 Penrose
Basic Electricity:Current, Voltage and
Resistance
8/12/2019 1 Electrical Theory
11/79
(c)2005 Penrose
Current (Amperage - I)
Current is the flow ofelectricity, much like
the flow of water in apipe. It is measured in Amperage as opposedto gallons per minute of
water.
8/12/2019 1 Electrical Theory
12/79
(c)2005 Penrose
Current
1 Amp = 6.28 x 10 18 electrons per second
1 Amp = 1 Coulomb per second Electron charge = 1.60219 x 10 -19 Coulombs Flows Negative Charge to Positive Charge
Electron! Electron!Electron!
8/12/2019 1 Electrical Theory
13/79
(c)2005 Penrose
Voltage (Volts - V or E)Voltage is the electrical
pressure in the system,much like water pressure.
Electrical pressure ismeasured in Volts asopposed to Pounds perSquare Inch. (ie: 110V likewater from a tap, 4160 likea fire hose)
8/12/2019 1 Electrical Theory
14/79
(c)2005 Penrose
Resistance (Ohms - R or )
Resistance is simply therestriction of current
flow in a circuit.Smaller wire(conductors) and poorconductors have higherresistance.
8/12/2019 1 Electrical Theory
15/79
(c)2005 Penrose
Resistance
eee e
ee
ee
e
ee
ee
e
Many Collisions = Heat!
Fewer Collisions = Less Heat!
8/12/2019 1 Electrical Theory
16/79
(c)2005 Penrose
Ohms Law Current, Voltage, and Resistance relate as
follow:
I = E / R
8/12/2019 1 Electrical Theory
17/79
(c)2005 Penrose
Electrical andMagnetic Fields
8/12/2019 1 Electrical Theory
18/79
(c)2005 Penrose
Magnetics
NorthSouth
Magnetic Flux
Magnet
8/12/2019 1 Electrical Theory
19/79
(c)2005 Penrose
Current Flow in Conductor
- +
Current Flowing in a Conductor
8/12/2019 1 Electrical Theory
20/79
(c)2005 Penrose
Generated Field Around
Conductor
+
8/12/2019 1 Electrical Theory
21/79
(c)2005 Penrose
Magnetic Field With Coil+
-
+
-
North Magnetic Pole
South Magnetic Pole
8/12/2019 1 Electrical Theory
22/79
(c)2005 Penrose
Interaction with Medium
NorthSouth
Magnetic Flux
MagnetMetal NS
8/12/2019 1 Electrical Theory
23/79
(c)2005 Penrose
Alternating CurrentElectricity
8/12/2019 1 Electrical Theory
24/79
(c)2005 Penrose
Electrical Properties Frequency Inductance (L)
Mutual Inductive Reactance (X L)
Capacitance (C)
Capacitive Reactance (X C) Phase Angle/Power Factor Impedance (Z)
8/12/2019 1 Electrical Theory
25/79
(c)2005 Penrose
Frequency
0 90 180 270 360
8/12/2019 1 Electrical Theory
26/79
(c)2005 Penrose
Inductance Stores electromagnetic
energy in its magneticfield
mH
dt di LV
t id v L
i0
)0()(1 2
21
LiW
I lags V
8/12/2019 1 Electrical Theory
27/79
(c)2005 Penrose
Mutual Inductance When 2 coils in close
proximity, a changingcurrent in one coil will
induce a voltage in asecond coil
0 90 180 270 360
N1 = 5 Turns100 Volts
N2 = 5 Turns100 Volts
8/12/2019 1 Electrical Theory
28/79
(c)2005 Penrose
Inductive Reactance X L
Inductive Reactance isthe AC Resistance of a
coil Presented as a
resistance in Ohms Frequency and
Inductance Dependant
fL X L 2
8/12/2019 1 Electrical Theory
29/79
(c)2005 Penrose
Capacitance
Stores energy in anelectric field
Dielectric between 2plates
The charged conditionis maintained until a
discharge path ispresent Causes current to lead
voltage
+
-
8/12/2019 1 Electrical Theory
30/79
(c)2005 Penrose
Capacitive Reactance X C
fC X C 21
8/12/2019 1 Electrical Theory
31/79
(c)2005 Penrose
IV
Phase Angle / Power Factor
In a coil or motor,current lags behindvoltage
This is represented asan angle or a fraction
of unity Adding C can improve
PF
0 90 180 270 360
8/12/2019 1 Electrical Theory
32/79
(c)2005 Penrose
fC X C
21 fL X L 2
DCResistance
Complex AC
Resistance
Impedance Z
22 )( C L X X R Z
8/12/2019 1 Electrical Theory
33/79
(c)2005 Penrose
Summary
Atomic Structure and Electron Movement Conductors, Semi-Conductors, Insulators
Basic Electricity: Current, Voltage andResistance
Electrical and Magnetic Fields Alternating Current Electricity: L, C, X L, XC, Z
8/12/2019 1 Electrical Theory
34/79
(c)2005 Penrose
AC Induction Motor
TheoryHoward W Penrose, Ph.D.Instructor
8/12/2019 1 Electrical Theory
35/79
(c)2005 Penrose
Basic Motor Circuit
Resistance Inductance Capacitance Phase Angle Inductive Reactance X L Capacitive Reactance X C Impedance
22 )( C L X X R
8/12/2019 1 Electrical Theory
36/79
(c)2005 Penrose
The Polyphase Induction Motor
StatorWindings
StatorLaminations
RotorBearing
Fan
8/12/2019 1 Electrical Theory
37/79
(c)2005 Penrose
Interaction of Rotor Fieldand Stator FieldInteraction of Two Magnetic Fields
Stator Field Rotor Field
N
S
Electrical Energyto
Mechanical Torque
8/12/2019 1 Electrical Theory
38/79
(c)2005 Penrose
Rotating Fields
8/12/2019 1 Electrical Theory
39/79
(c)2005 Penrose
Rotating Field and Rotor Cage
8/12/2019 1 Electrical Theory
40/79
(c)2005 Penrose
Rotor Cage
8/12/2019 1 Electrical Theory
41/79
(c)2005 Penrose
Output Torque
8/12/2019 1 Electrical Theory
42/79
(c)2005 Penrose
Operating Motor
8/12/2019 1 Electrical Theory
43/79
(C)2004, Howard W Penrose,Ph.D., All rights reserved
Insulation System
Considerations for MCAand Motor ConnectionsQuantum Mechanics and Motor Diagnostics
8/12/2019 1 Electrical Theory
44/79
(c)2005 Penrose
STATOR LAMINATIONS
8/12/2019 1 Electrical Theory
45/79
(c)2005 Penrose
Stator Failure Modes Turn to Turn Coil to Coil Open Circuit
Phase to Phase Coil to Ground
8/12/2019 1 Electrical Theory
46/79
(c)2005 Penrose
Insulation Diagram of Motor
Ground
Phase A
Phase B
Phase C
Circuit CapacitanceChanges due to chargeEffects of atoms inInsulation medium.Dipoles are created
As electric field crosses Atoms. As they alignCapacitance increases.
8/12/2019 1 Electrical Theory
47/79
(c)2005 Penrose
- -
The Dipole
+Neg Potential Pos Potential
Di l M ti i O ti
8/12/2019 1 Electrical Theory
48/79
(c)2005 Penrose
Dipolar Motion in Operation
GRND
Wire
Wire
Voltage
Capacitance
High
Low
MegOhms
High
Low
High
High
Ground Insulation
Di l M i i DC T
8/12/2019 1 Electrical Theory
49/79
(c)2005 Penrose
Dipolar Motion in DC Tests
GRND
Neg
Neg
Capacitance
Low
MegOhms
Low
High
High
MegOhms
Time
Pos
Dipolar Motion in Surge Test
8/12/2019 1 Electrical Theory
50/79
(c)2005 Penrose
Dipolar Motion in Surge Test
Conductor 1 Conductor 2
Voltage
Time
Impulse
Overcomes DipolarSpin and CircuitCapacitance
Requires Higher Voltage as a ResultIn order to cross air gap (Paschen)Potentially Destructive!!!
Accelerated Insulation Degradation
8/12/2019 1 Electrical Theory
51/79
(c)2005 Penrose
Accelerated Insulation Degradation
Arc during fault detection using surge test.
The separated insulation is the result of the arc (burned). The grey area on thecopper is carbonized insulation.
Dipolar Motion in MCA 1
8/12/2019 1 Electrical Theory
52/79
(c)2005 Penrose
Dipolar Motion in MCA - 1
wire
wire
wire
wire
wire
wire
Good PhasePhase Angle: 77 degreesCurrent/Frequency: -44%
Dipolar Motion in MCA 2
8/12/2019 1 Electrical Theory
53/79
(c)2005 Penrose
Dipolar Motion in MCA - 2
wire
wire
wire
wire
wire
wire
Bad PhasePhase Angle: 73 degreesCurrent/Frequency: -40%
CapacitiveDefect
Before and After Defect
8/12/2019 1 Electrical Theory
54/79
(c)2005 Penrose
Before and After Defect
1-2 1-3 2-3
Resistance 0.6821 0.6798 0.6865
Impedance 21 21 39
Inductance 8 8 7
Phase Angle 77 76 76
I/F -47 -45 -47
Ins Resist >99
1-2 1-3 2-3
Resistance 0.6786 0.6797 0.6819
Impedance 21 21 39
Inductance 8 8 7
Phase Angle 77 77 76
I/F -47 -43 -47
Ins Resist >99
MCA Result on20 hp with contamination and slight
phase to phase defect. Still running.
MCA test results following surge testfrom previous example. Trips on start.
8/12/2019 1 Electrical Theory
55/79
(c)2005 Penrose
Time to Failure
Estimation Techniques Howard W Penrose, Ph.D.
T-Solutions, Inc.
8/12/2019 1 Electrical Theory
56/79
(c)2005 Penrose
Concept of TTFE Setting test frequencies such that faults can
be detected in advance Setting alarms at a point where fault
detection is effective Knowing that failures are random
Know that the resistance to failure decreasesfollowing detection of a CBM alarm
C di i Di d E l
8/12/2019 1 Electrical Theory
57/79
(c)2005 Penrose
Source: reliability-centered maintenance, Nowlan and Heap
Condition-Directed Example
Operating age (time T)
Inspection Interval
R e s
i s t a n c e
t o f a i l u r e B (Insulation begins to degrade between turns)
P (Interturn insulation degradation detection)
F (Winding fails)T
( F-P)
A (New Motor Installed)100%
0%
8/12/2019 1 Electrical Theory
58/79
(c)2005 Penrose
Example of TTFE in
MCA
8/12/2019 1 Electrical Theory
59/79
(c)2005 Penrose
This Presentation Stages of Winding Failure Causes and Effects Trending Time to Failure Discussion
< 600 Vac Standard, integral, three phase motors,
operating an average of 4000 hours 50% load, balanced voltage, good power quality,
constant load
8/12/2019 1 Electrical Theory
60/79
(c)2005 Penrose
Insulation Breakdown Contamination
Moisture and electric fieldexpansion
Gasses, vapors, dust, etc.
Arc Tracking High Current Between
Conductors
Thermal Aging (10 oC)
Partially Assembled 125 horsepowerMotor in repair shop
8/12/2019 1 Electrical Theory
61/79
(c)2005 Penrose
Insulation Breakdown VFD Applications
Partial Discharge
Mechanical Faults Stress cracking Parts Faults
Stators awaiting assembly after rewind
8/12/2019 1 Electrical Theory
62/79
(c)2005 Penrose
Stages of Winding Failure Time to Failure
Severity of the Fault Potential Between Conductors
Type and Amount of Insulation Cause of the Fault Cycling and Load
Contamination, Thermal, MoistureIncursion, Corona, Transients, Overloads,etc. may initiate fault.
8/12/2019 1 Electrical Theory
63/79
(c)2005 Penrose
Stage 1 Insulation between conductors stressed Changes to R and C between conductors
High temps and reactive faults Carbonization begins to occur MCA values of Fi and I/F begin to change
8/12/2019 1 Electrical Theory
64/79
(c)2005 Penrose
Stage 2
Fault becomes more Resistive Mutual Inductance between good and bad I2R losses increase at point of fault Motor may start tripping although may run
after short cooling period (ins res increasesas insulation cools)
8/12/2019 1 Electrical Theory
65/79
(c)2005 Penrose
Stage 3 Insulation breaks down Possible explosive rupture Vaporization of windings
Inductance and sometimes resistance maychange
Stage 3 winding failure
8/12/2019 1 Electrical Theory
66/79
(c)2005 Penrose
Review
MCA Requirement: Resistance Loose connections, Broken Wires (~5%) Impedance and Inductance Rotor position or contaminated
windings. Also, used for rotor test in assembled equipment. (Parallelgood, Unparallel bad)
I/F and Fi Early winding shorts (I/F: +/-2; Fi: +/-1) Insulation Resistance Ground Faults (5 MOhm/100 MOhm)
Combination used for troubleshooting or trending
Comparative tests: Assumes that phases do not fail at samerate
How Trended
8/12/2019 1 Electrical Theory
67/79
(c)2005 Penrose
How Trended
AC Motors % unbalance: R, Z and L Phase Diff: I/F and Fi
Reading: Insulation Resistance
Induction Rotors: Neednumerical method (RotorGrading System RGS)
MCABeing used to confirm the
Winding voltage connection
in a submersiblePump.
AC Rotating Machine Testing
8/12/2019 1 Electrical Theory
68/79
(c)2005 Penrose
AC Rotating Machine Testing
Reading Change fromBaseline
Severity
R, Z, L < 3% Green
R, Z, L >3 and 5% Red
Fi, I/F 1 and 3 Red
Trended Reading
8/12/2019 1 Electrical Theory
69/79
(c)2005 Penrose
Trended Reading
AC Motor 2
8/12/2019 1 Electrical Theory
70/79
(c)2005 Penrose
AC Motor 2
PdM Testing Frequency
8/12/2019 1 Electrical Theory
71/79
(c)2005 Penrose
PdM Testing Frequency
Motor Type Clean/DryEnvironment
ModerateEnvironment
Dirty/WetEnvironment
3-PhaseNon-Critical
12 Mo 9 Mo 6 Mo
3-PhaseProduction
6 Mo 6 Mo 3 Mo
3-PhaseCritical
3 Mo 2 Mo 1 Mo
DC Motors 6 Mo 6 Mo 3 MoTransformer 12 Mo 9 Mo 6 Mo
Estimating Time To Failure!
8/12/2019 1 Electrical Theory
72/79
(c)2005 Penrose
g
What To Do Once A Fault IsDetected
Motor ready for test in motor repair shop
8/12/2019 1 Electrical Theory
73/79
(c)2005 Penrose
What Makes Fault
Detection Difficult? Time To Failure
Application Type of Fault Severity of Fault
Based upon Stages of Failure, Insulation failsover time
8/12/2019 1 Electrical Theory
74/79
(c)2005 Penrose
Winding Contamination
0
1
2
3
45
6
7
Annual 9Months Semi Quarterly Monthly
Test Frequency
T i m e
t o A c
t i o n
( M o
n t h s
)
8/12/2019 1 Electrical Theory
75/79
(c)2005 Penrose
Turn to Turn Shorts
0
2
4
6
8
10
Annual 9 Months Semi Quarterly Monthly
Test Frequency
T i m e
t o A c
t i o n
( M o n
t h s
)
1pt2pt3pt>3
8/12/2019 1 Electrical Theory
76/79
(c)2005 Penrose
Phase to Phase or Coil to Coil
-1
01
2
3
45
6
7
Annual 9 Months Semi Quarterly Monthly
Test Frequency
T i m e t o
A c
t i o n
( M o
n t h s
)
1pt
2pt
3pt
>3
8/12/2019 1 Electrical Theory
77/79
(c)2005 Penrose
TTFE Software
Final Comments
8/12/2019 1 Electrical Theory
78/79
(c)2005 Penrose
When is TTFE effective? Technology can detect developing faults
(Condition-Based) Optimized testing frequency or continuous
monitoring A history exists or can be obtained Multiple-Technology approach to confirm
condition and stage of failure
Understanding that the functional failure is notinstantaneous and some forcing function drivesthe failure
Action is taken on findings: Risk-based decision
8/12/2019 1 Electrical Theory
79/79
SUCCESS by DESI GN
5 Dogwood LnOld Saybrook, CT 06475
Ph: 860 575-3087 Fax: 860 577-8537http://www.motordoc.nethoward@motordoc net