3 PHASE FOR
DUMMIESAND SMARTIES,
TOO.
Introduction
What is Three-Phase Power
Why Do We Need Three Phase Power
AGENDA
Basic Equations
Vector Representation
Wye and Delta Coil Arrangement
Multi-Pulse Configurations
Rectification
What is Three-Phase Power
Three separate sinusoidal voltages are generated with a 120º phase shift between each phase.
0º
120º 240º
INTRODUCTION
This package introduces the reader to some of the fundamentals needed to understand threephase power.
Why Do We Need Three Phase Power?
What are the Advantages?
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One of the greater motivators is cost savings.
Higher efficiency associated with a three-phase system saves utility costs.
A three-phase system will save on both material and labor.
A three-phase system requires only one core, instead of three separate cores.
Three single phase cores will consume more power than a single three-phase core.
Mounting hardware is only needed for one device.
Line currents from the source can be lower, as the phases are dividing the power into a third
of the power per phase as would be required from a sing phase.
• Reduced currents can use smaller conductors, making winding easier.
• Where DC is required, the reduced ripple on three-phase systems will result in smaller, less
expensive filtering components.
BASIC EQUATIONS
• Voltage x current x √3 is the power entering a three-phase system as looked at from the source to a
black box transformer.
• Current in a delta connected winding is line current from the supply divided by √3 .
• Line to neutral voltage is always line to line voltage divided by √3.
• Cosine of 30 degrees = .8660, which equates to half of the √3. Three-phase factors are derived from
this value.
• The mirror image triangles formed by bisecting a line connecting phases are called 1,2, √3 triangles,
where 2 is the proportional length of the phase to neutral vector of a wye configuration. (Illustration
on following page).
• A delta connection can be represented as a wye by bisecting rays drawn from apexes to a virtual
center neutral (N).
FIGURE 1
N
FIGURE 2
N
FIGURE 3
N
VECTORS
• The extracted and bisected triangle illustrates the 1, 2, √3 triangle. Normalizing magnitude 2 to
1 gives us (2 x √3)/2,
for a 1 to √3 ratio of line to neutral (L-N) to line-to-line (L-L) voltages.
0º
60º
30º
240º
120º
2
1
90º
√3
√3
2 x √3
• Since relative phase angles between coils always remains constant, there is a phase shift of 30
degrees when reconnecting a delta as a wye. (See figure below). Notice that polarities in the
delta and wye coils remain the same with respect to their phase.
0º gives 6 distinct L-N phases
• The wye L-N will lead the delta virtual L-N by 30º. Transformation
30º
shifted from each other by 30º.
Rectification
with two 3-phase
bridges would produce a 12 pulse output.
VECTORS
• Vectors represent amplitude and direction. In systems of propagation in time, values are
instantaneous.
• A vector is defined by its polarity, magnitude, and angle.
• Dots on vectors, by convention, will indicate relative polarities of vectors at their relative
points in time on three-phase rotating vector diagrams.
• Similarly transformer schematic coils and indicate same polarity for windings relative to their
phase.
• The time domain vector diagram below indicates the positions of sinusoidal waveform peaks
in their time shifted positions conceptualized on a 0 - 2 p radian, or 0 to 360º span on a circle.
• Just like batteries, polarities can add or subtract.
(360º)
0º
240º
120º
WYE AND DELTA COIL ARRANGEMENTS
THE FIRST IMAGE BELOW ILLUSTRATES A SIMPLE VECTOR ANALOG COIL SCHEMATIC REPRESENTATION. THE COILS CAN ALSO BE REPRESENTED AS
COILS IN THEIR VECTOR ARRANGEMENT AS SHOWN IN THE SECOND IMAGE :
MULTI-PULSE SYSTEMS
THERE ARE NUMEROUS WAYS TO CREATE PHASE SHIFTED SETS OF DELTA AND WYE WINDINGS FOR 6, 12, AND 24 PULSE SYSTEMS, AS WELL AS
POLYGONAL AND “WINDMILL” GEOMETRIES FOR 18-PULSE SYSTEMS. FOR THE BASE TIME PERIOD OF AN ENTIRE CYCLE OF YOUR OPERATING
FREQUENCY, YOU WOULD COUNT THE NUMBER OF PULSES IN THE PERIOD. FOR 400 Hz, THE TIME PERIOD WOULD BE 2.5ms. EXTENDED DELTAS AND
ZIG-ZAG WYES ARE A LEGACY TOPOLOGY FOR 15 DEGREE SHIFTS TO OFFSET TWO 6 PULSE DIODE BRIDGES ON DELTAS AND WYES TO CREATE 24
PULSE SYSTEMS. ON SYSTEMS WHERE WYE AND DELTA TURNS RATIOS DO NOT PERFECTLY MATCH RATIOS NEEDED FOR EQUAL VOLTAGES,
INTERPHASE TRANSFORMERS ARE USED TO ENSURE MORE BALANCED VOLTAGES FROM BRIDGES. THE ILLUSTRATION BELOW SHOWS DELTA WYE
AND EXTENDED DELTA AND ZIG-ZAG WINDINGS CREATING A 24 PULSE SYSTEM:
NAVIGATING Q&A SESSIONS
1.
Know your material in
advance
2.
Anticipate common
questions
3.
Rehearse your responses
Maintaining composure during the Q&A session is
essential for projecting confidence and authority.
Consider the following tips for staying composed:
•
Stay calm
•
Actively listen
•
Pause and reflect
•
Maintain eye contact
SPEAKING IMPACT
Your ability to communicate effectively
will leave a lasting impact on your
audience
Effectively communicating involves not
only delivering a message but also
resonating with the experiences, values,
and emotions of those listening
DYNAMIC DELIVERY
Learn to infuse energy
into your delivery to leave
a lasting impression
One of the goals of
effective communication
is to motivate your
audience
Metric
Measurement
Target
Actual
Audience
attendance
# of attendees
150
120
Engagement
duration
Minutes
60
75
Q&A
interaction
# of questions
10
15
Positive
feedback
Percentage
(%)
90
95
Rate of
information
retention
Percentage
(%)
80
85
FINAL TIPS & TAKEAWAYS
Consistent rehearsal
•
Strengthen your familiarity
Refine delivery style
•
Pacing, tone, and emphasis
Timing and transitions
•
Aim for seamless, professional delivery
Practice audience
•
Enlist colleagues to listen & provide feedback
Seek feedback
Reflect on performance
Explore new techniques
Set personal goals
Iterate and adapt
SPEAKING ENGAGEMENT METRICS
Impact factor
Measurement
Target
Achieved
Audience interaction
Percentage (%)
85
88
Knowledge retention
Percentage (%)
75
80
Post-presentation
surveys
Average rating
4.2
4.5
Referral rate
Percentage (%)
10
12
Collaboration
opportunities
# of opportunities
8
10
THANK YOU
Brita Tamm
502-555-0152
brita@firstupconsultants.com
www.firstupconsultants.com