Data Sheets and Data Sheet Guide API 546 third edition is an improved and comprehensive synchronous machine specification that reflects current user performance requirements for highly e
Trang 1The third edition of this common performance standard for large synchronous machines
B Y B I L L L O C K L E Y , M A R K C H I S H O L M , T R A V I S G R I F F I T H ,
G A B E D ’ A L L E V A , & B A R R Y W O O D
written by and for users, consultants, and manufacturers to provide a common perform-ance standard for large synchronous machines The standard is
designed as a stand-alone document listing the requirements
of all aspects of a synchronous machine When compared with earlier editions, this edition has various enhancements designed to make it easier to purchase or specify a more durable machine It has new requirements in some areas such as excitation systems, frame vibration, and insulation tests, as well as improved sections concerning dynamic analysis and thermally induced vibration changes To reduce the risk
of confusion, it should be used with the supplied data sheets Digital Object Identifier 10.1109/MIAS.2010.938394
© FOTOSEARCH
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Trang 2Durability of Synchronous Machines
Large synchronous motors and generators are often the most
important pieces of electrical machinery in large process
plants such as refineries, compressor stations, chemical plants,
and other process facilities API Standard 546 third edition
[1] has been written to assist users, consultants, and
manufac-turers of these large synchronous machines Users and
consul-tants can use it to specify a high-quality machine and more
easily compare proposals, while manufacturers have a standard
specification that will make their proposals easier to produce
As part of the revision process while developing this
third edition, the working group looked at issues that had
been concerning users regarding the durability of the
machines and attempted to address these issues We believe
that the changes have made the document better at
defin-ing what is needed for a durable cost-effective machine
The standard uses data sheets to define particular
re-quirements and equipment offerings It is essential that users
fill in these data sheets so that manufacturers know exactly
what is required of their product There are separate data
sheets for motors and generators as well as for North
Amer-ican and international practices and standards To assist
users in filling out the data sheets, the data sheet guides
have been updated
Why Use Synchronous Machines?
Generally, a power supply needs to run at a fixed
predeter-mined frequency (typically 50 or 60 Hz) This requirement
dictates the use of synchronous generators or at least induc-tion generators with frequency converters
For motor applications, a more comprehensive evalua-tion may be required to determine the most appropriate solution Some of the factors are summarized in Table 1
In addition to these factors, there are other softer, less readily quantifiable issues that a user may be concerned about, e.g., excitation systems, control systems, and reliabil-ity These factors have been more thoroughly addressed in the latest edition of the standard
History of the Standard
In 1986, at the completion of the document for the second edition of API Standard 541, Form-Wound Squirrel-Cage Induction Motors 250 hp and Larger, participants concluded that a similar standard was needed to address synchronous machines A task force was formed from the mutual API-Petroleum and Chemical Industry Committee motor resource group The task force included representation from process industry members and large machine manufacturers The first edition of API Standard 546, Form-Wound Brushless Synchronous Motors, was published in June 1990 Despite the similarity of participation in the 541 and 546 groups, substantive differences existed between the two documents irrespective of the technological differences
The 541 task force was then reconstituted to review and update the induction motor standard, resulting in the print-ing of the third edition in 1995 As before, work on the
TABLE 1 SYNCHRONOUS AND INDUCTION MOTOR COMPARISON.
Factor Induction Advantage Synchronous Advantage
Capital cost
Power consumption and efficiency
Power factor
Starting current
Accelerating torque margin
Pulsating/oscillating torque during
starting
Current pulsations for
nonsteady-state loads such as reciprocating
compressors
Rotor inertia (application
dependent)
Suitability for adjustable speed
drive
Two-pole applications
Lead-time
Ride-through supply interruptions
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Trang 3second edition of 546 started immediately after completion
of 541 To keep within the American National Standards
Institute mandated reissue/reaffirm schedule, the task force
labored on an expedited basis to issue the standard in June
1997 Important changes were the inclusion of generators
(elevated from parenthetical statements at the end of
para-graphs) and establishment of a power rating, so the title
was changed to Brushless Synchronous Machines—500 kVA
and Larger Generator data sheets were added, but the
sub-stantive differences still existed
As before, the 541 group revised and published its fourth
edition in 2004 The API Subcommittee on Electrical
Equipment (SOEE) also directed that the substantive
dif-ferences be resolved, and a mutual list of electrical standard
paragraphs be developed where commonalities existed,
i.e., insulation systems and mechanical design features API
also inserted a new group in the schedule to address the needs
for intermediate-sized induction machines, and API 547,
General-Purpose Form-Wound Squirrel Cage Induction Motors—
250 hp and Larger, was introduced in 2005
At the API 2005 Spring Refining Meeting, the present
546 task force was formed and the review cycle initiated
Improvements are herein detailed
API members recognize the distinctive nature, severe
duty, and special operating demands for electric machines
within their process industry The API series of electrical
standards are continuously evolved to address those
con-cerns and communicate specific requirements to various
internal and external engineering organizations Importantly,
they establish minimum design, performance, and testing
criteria for manufacturers This also serves to generate
common technical understanding and standardize machines
to improve operating reliability and reduce cost
Significant changes have occurred in both the process and manufacturing industries It is common for large machine manufacturers to offer both induction and synchronous equip-ment, so the harmonization in language between the 541–
547 induction and the 546-type synchronous machines remained an important issue Users’ needs have also changed with heightened attention toward accomplishing general-purpose requirements without having to procure special-purpose machines Improvements in materials, design, and construction of machines, as well as changes in codes, regulations, other standards, and implementation of inter-nationally based mandates [i.e., International Electro-technical Commission (IEC) and International Organization for Standardization] have spurred equal development within API 546
Typical synchronous machine rotors are shown in Figure 1 (slow speed machine) and Figure 2 (higher speed machine) Contents of the Standard
Some areas where the third edition has been signifi-cantly changed from its predecessor are given in the subse-quent sections
Mechanical Requirements
As noted in the “History of the Standard” section, multiple interests affect the writing and consensus of any document API 541 and 546 have traditionally reflected the input and experience of electrical engineers Within the API’s Com-mittee on Refining Equipment (parent of the SOEE) is another interest group: the Subcommittee on Mechanical Equipment (SOME) These equally skilled group of engi-neers have concerns usually related to the driven equipment, such as pumps, compressors, and other nonelectrical rotating devices Through past balloting procedures, SOME members had comments and desired to insert the API 600 (mechanical series) experience They saw a need to generate a common rotational dynamics approach across all API machines
A small team of SOME members assembled and recom-mended mechanical changes, which were considered and implemented where appropriate by the 546 task force Many
of the dynamic analysis requirements suggested by the SOME group were adopted, such as the requirement to up-date the dynamic model if the test results varied from prediction by more than 5% and the methods for handling nonmassive foundations The requirements for dynamic analyses are now more clearly defined However, the prime requirements for achieving satisfactory vibration perform-ance and verifying separation margin from rotor and support system critical speeds were maintained as being perform-ance on the test stand rather than by analysis
The bearing housing and shaft vibration limit figures [Figures 4.1(a) and (b) and 4.2(a) and (b) in API 546] have been updated to include both U.S customary and metric units and to make them more readable Also, the figures for the shaft vibration limits have been updated to make them more consistent with the vibration limit equations
In this context, the allowable shaft vibration has been slightly reduced for higher speed machines so that a 3,600 r/min machine now has a maximum unfiltered peak-to-peak vibration displacement of 46 lm (1.83 mil) versus the
2
A higher speed rotor (Photo courtesy of General Electric.)
1
A slow speed rotor (Photo courtesy of General Electric.)
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Trang 4previous 51 lm (2.0 mil) Otherwise, the vibration limits
remain the same as in the 546 second edition
Excitation System
An area where some users’ experience indicated that
syn-chronous motors had issues with reliability was the
excita-tion system, including the power supply to the exciter and
the field application package, plus the stationary and
rotat-ing portions of the exciter The workrotat-ing group looked at
the areas where problems had been reported and developed
requirements for those parts of the excitation system Some
of the issues addressed were the following:
Con-trol Supply Voltage: This was addressed by requiring
a constant voltage transformer, phase-controlled
rectifier, or other means to maintain at least 95%
nominal exciter input voltage for 2 s for a 50%
volt-age dip and by requiring input surge protection
required, plus an overvoltage protection circuit, a
limit on worst case junction temperature Diode
fail-ure detection is listed as an option for fixed-speed
applications Device test and rotor monitoring
sys-tems are also options
wind-ings are now required to be capable of withstanding
spikes from the solid-state switching, plus common
mode voltages, and to be braced adequately for
cen-trifugal forces when applicable
for field application of a motor (speed, current, time,
etc.) are not specified; however, the method must be
jointly agreed between the user and manufacturer
In addition, wiring methods in the control panel are
specified to improve reliability and avoid interference
between systems
ther-mal requirements are specified, plus a requirement
that the resistor be waterproof
We believe the requirements introduced will improve
performance in these areas and make synchronous motors
more reliable for users
Partial-Discharge Monitors
Partial-discharge (PD) monitoring systems are becoming
more common on higher voltage fixed-speed machines to
assist in predicting and avoiding stator winding insulation
problems The standard now lists this equipment as an
option and gives requirements for the PD sensors,
includ-ing internal wirinclud-ing, terminal boxes, output terminals, and
output devices
Insulation Quality
One concern with higher voltage (typically more than
4,160 V) machines in general is the possibility of voids in
the stator insulation, especially with the coils that are near
to full-line voltage Internal insulation voids tend to cause
excessive PD across the voids in these stator coils, which
may eventually lead to a winding failure
The standard has sections listing optional tests and
inspec-tion to reduce the possibility of PD-induced failures in service
When specified, during winding and coil impreg-nation, two extra sacrificial coils shall be made and impregnated along with the rest of the winding, and after surge tests at higher than standard levels, they are cut into segments and inspected Any visi-ble voids would be cause for further discussion
Factor Tip-Up Test” specified to be performed along with the other insulation tests This test looks at the change in insulation power factor from a rela-tively low voltage to a voltage at approximately operating voltage A greater than expected increase
is a possible indication of excessive voids IEEE Stan-dard 286 [2] or IEC StanStan-dard 60894 [3] is called
up to provide the requirements of this test
de-termines the PD performance of the winding for each phase IEEE Standard 1434 [4] or IEC TS 60034-27 [5] are used as the basis for this test
slightly different and has variable levels of acceptable performance under some of these tests Therefore, there are not yet hard and fast rules indicating what void size, tip-up figures, or PD measurements are acceptable The acceptance criteria should be dis-cussed and agreed upon between the user and man-ufacturer before the tests are done
crite-ria; however, the API task force concluded that the tests were still useful in many cases Different manu-facturers may see a wide variation of results in some tests for insulation systems, which perform equally well In many cases, the tests provide useful data to compare with results from other machines from the same manufacturer In future, we expect that better defined acceptance criteria will be developed
TEWAC Heat Exchanger Thermal Test
There have been cases in the field where totally enclosed water-to-air-cooled (TEWAC) machines have not been able
to provide full power output because the water-to-air heat exchanger has not been capable of dissipating the heat gen-erated by the machine, even though the machine losses were per design To ensure that the heat exchangers are adequate to handle the heat generated with the specified cooling water conditions and flow, an optional “Heat Exchanger Performance Verification Test” has been included
in the document This minimum 4-h test requires the cool-ing water flow and temperature to be maintained as close as practical to rated conditions while the machine is operating
in the factory at rated temperature With rated cooling water conditions, the air out of the heat exchanger into the motor
practical, this may be performed as part of the complete test Alternatively, the user and manufacturer may jointly develop an alternative test if the specified test is impractical
Data Sheets and Data Sheet Guide
API 546 third edition is an improved and comprehensive synchronous machine specification that reflects current user performance requirements for highly engineered machines
Trang 5significant user information The standard requires
com-pleted data sheets and identifies 127 bulleted paragraphs
(), where a decision or additional information is required
by the user An API 546 machine cannot be built without a
data sheet The basis of the standard is for the manufacturer
to design and build an engineered machine to meet the exact
requirements of the end user as defined by the 11-page data
sheet An incomplete data sheet, incorrect information on a
data sheet, or worst of all no data sheet may result in an
inad-equate or incompatible machine design requiring costly
modification or redesign
The API 546 third edition data sheets and supporting
data sheet guides have been extensively revised and
up-dated There are separate multipage sheets for motors and
generators with further subdivisions between North
Amer-ican and international practices
The data sheet changes include: layout and format
revi-sions, changes to technical content, and user-selected
inspec-tion and tests The new data sheets are structured with the
sections as shown in Table 2
The changes made in the data sheet format include
the following:
processor-based format to a spreadsheet format
data sheet items with a single keystroke is included
user-completed and manufacturer-user-completed line items
are included
to applicable line items for easy reference
added to the customary English unit motor and
gen-erator data sheets
typical standard default selection
preselected on the data sheet testing section
technical requirements
to 11
The following are basic descriptions of the contents of each of the data sheet sections mentioned in Table 2 The General section covers basic machine ratings, site data, enclosure types, machine mounting, electrical sup-ply system, and bearing information Some of the sig-nificant data sheet technical changes in the General section include:
of 85 dBA or other user-specified sound level
third-party certification added on metric data sheets
data sheets
the Accessories section to under the TEWAC enclo-sure section
informa-tion was moved from the Accessories secinforma-tion to under the WP II enclosure section
The Lubrication System section describes the type of lubrication, method, and supply source of the machine lubrication A data sheet change in the Lubrication System section includes:
items from the Lubrication System section, since machine manufacturer normally does not provide an external skid with lubrication pumps
The Special Conditions section lists options for the user to select one piece shaft forging, special vibration requirements, cost data for efficiency evaluation factor determination, local code requirements, special overspeed requirement, and any user-identified external forces on machine enclosure that may affect performance A data sheet change in the Special Conditions section includes:
TABLE 2 DATA SHEET LAYOUT.
Section Headings Motor Data Sheets Generator Data Sheets
2 Lubrication system Lubrication system
3 Special conditions Special conditions
4 Main conduit box Main conduit box
7 Driver equipment information Driver equipment information
9 Motor data—first section Generator data—first section
10 Motor data—second section Generator data—second section
11 Stator and rotor winding repair data Stator and rotor winding repair data
12 Analysis, shop inspection, and tests Analysis, shop inspection, and tests
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Trang 6new line items added for a one-piece shaft forging
option, user-supplied list of applicable local codes,
and unusual overspeed requirements
The Main Conduit Box section provides line items for
the user to specify power supply feeder information and a
listing of manufacturer-installed accessories
The Accessories section contains the user-specified machine
space heater information, temperature detectors, vibration
detectors, monitors for equipment health monitoring, and
power supply details for auxiliary mounted fans Some of
the specific changes in the Accessories section include:
listing new individual line items for shaft grounding
brush replacement monitor, test device for rotating
electronic components, rotating diode failure
detec-tion, and online rotor monitoring system
per-manent magnet generators were added to the existing
constant voltage transformer and phase-controlled
rec-tifier power supply options
En-closures” was added for the user to select enclosure
loca-tion on the machine and conduit/cable entry localoca-tion
added for the user to specify quantities, power
sup-ply, location, and enclosure type for nonshaft-driven
auxiliary fans
The Controls section lists the user-selected excitation
power source as well as external controls panel and
panel-mounted devices to be provided by the manufacturer In
addition, the generator data sheets list excitation, type
description, response information, and ceiling voltage
in-formation to be provided by the manufacturer after the
order placement
The Driver (generator) or Driven (motor) Equipment
Infor-mation section lists line items where the user or
manufac-turer provides mechanical load information descriptions
and data for motor loads and generator drivers
The Miscellaneous section is for the user to select paint
requirements, technical documentation and certifications,
instruction manuals, shipment information, and any
spe-cial identification or nameplates The Miscellaneous section
changes include new line items for the user to specify:
test documentation
op-tional tests
as-sembled before shipment
The Generator and Motor Data—First section lists line items
for the manufacturer to provide nameplate data, efficiency,
exciter data, and rotor construction-type information with the
proposal It also lists options for the user to select whether
guaranteed efficiencies are required Some of the changes to
the Generator and Motor Data—First section include:
effi-ciencies and results of the unbalance response analysis
if specified on both generator and motor data sheets
for loads such as reciprocating compressors where the torque requirements vary through a revolution
of the motor, a line item option was added for the manufacturer to supply current variation informa-tion, calculated efficiencies, and efficiency calcula-tion method on motor data sheets
The Generator and Motor Data—Second section provides areas where the manufacturer provides bearing dimensions data, machine parameters, and preliminary parameters to
be supplied with the proposal One of the changes to the Generator and Motor Data—Second section is the addition of
a new subsection for the user to select an option for the manufacturer to supply preliminary parameters with the proposal for user system studies
The Stator and Rotor Winding Repair Data section lists the stator coil details and rotor winding information to be provided by the manufacturer, after the order is placed for use, in the event future repairs are required
The Analysis, Shop Inspection, and Tests section provides a broad list of factory tests that can be selected as required by the user to be witnessed or observed Here, the data sheet guide can be very useful to determine which optional factory tests should be selected The required coordination meeting, optional design review meeting, and a factory inspection option are listed for the user to consider Some
of the significant data sheet technical changes in the Analy-sis, Shop Inspection, and Tests section include new line items for the user to select the following:
standard lists 12 suggested discussion and review items for this meeting
sched-uled factory tests; although this option is in the body of the API 546 second edition, it was not listed
as a data sheet option
inspection for voids and to check groundwall insu-lation thickness
future PD tests and insulation condition
and above
ma-chines other than four and six poles
Clearly, there is a significant amount of information that must be evaluated to specify an API 546 machine The data sheets list all the API 546 options and topics where addi-tional information must be provided A detailed review of the data sheets can give the user the opportunity to consider each
of the 127 bulleted items for a comprehensive specification
The Appendix D—Motor Data Sheet Guide and Appen-dix E—Generator Data Sheet Guide given in API 546 provide instructions on how to complete the motor and generator data sheets Instructions for every topic in every section of the data sheets are given The guide was prepared by selected members of the working group to provide clear, concise, and easy to understand instructions on how to fill
Trang 7on electrical and mechanical design, which provides
guid-ance to both the infrequent user and expert user on
select-ing data sheet accessory options and when to select specific
machine tests
Thermal Stability Explanation
A requirement that has been included in the testing section
of the previous edition and kept in the latest edition is for
the thermal stability of the machine to be proven This is
achieved by comparing the vibration levels of a cold machine
with one at full operating temperature If the rotor develops
a bow (or thermal growth causes components to expand
unevenly) as its temperature changes with load, then the
vibration of the shaft in its bearings will change
The requirements of the standard have not changed
from the previous maximum permitted vector shift being
50% of the allowable running speed vibration, but the
acceptance criteria have been difficult to interpret The
explanatory notes from the API 541 Induction Motor
Stan-dard were adapted and included as an Appendix to API 546
to assist with interpretation of acceptable vector shifts and a possible option to further check stability
The polar plots shown in Figures 3 and 4 are taken from the document and illustrate typical acceptable and unac-ceptable thermal vector shift situations, respectively
Operation on ASDs
Motors on ASDs have some extra issues that must be addressed Depending on the application and the drive selected, these may include:
caused by high rate of change of voltage (dV/dT) and displaced neutrals
resonances
in the waveform
The standard has requirements listed in various sections
to address these issues
Frame Vibration
Some recent situations have arisen where portions of a machine frame had unacceptably high levels of vibration, while the shaft vibration and the bearing housing vibration were well within the required limits These situations were due to frame resonances being excited by some normally occurring force, which would not be a concern if the reso-nance were not present The standard now imposes limits
on frame vibrations At shaft height, the vibration of any loaded structural member of the frame shall not exceed two times the permitted bearing housing vibration For designs that do not have structural members in this area, the manu-facturer and user should agree on criteria before the tests There has not yet been extensive data available on these frame vibrations and the effects, but based on recent expe-rience and available measurements, the task force con-cluded that these figures were reasonable However, future revisions of the standard may have changes in this area as more test data is acquired
Other Revisions
Other changes of note include:
supersyn-chronous machines
synchro-nous rotor construction
failure and at least five years of uninterrupted contin-uous operation (from 20 years minimum with three years continuous)
machines, i.e., 4.16 kV versus 4 kV and 13.8 kV versus 13.2 kV
level of the machine shall not exceed 85 dBA at any location at a reference distance of 1 m (3 ft)
pulsating torques in accordance with IEEE 1255 [6]
4
Resultant Vector:
1.46 mil at 150 °
Hot Vector:
1.2 mil at 120 ° 0.93 mil at 45Cold Vector:°
0.8 mil 1.6 mil
90 °
0 °
180 °
270 °
Example of an unacceptable thermally induced
vibration change.
Resultant Vector:
0.73 mil at 10 °
Hot Vector:
1.13 mil at 70 °
Cold Vector:
0.93 mil at 110 °
0.8 mil 1.6 mil
90 °
0 °
180 °
270 °
3
Example of an acceptable thermally induced
vibration change.
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Trang 8default to TEWAC or totally enclosed air-to-air
cooled (TEAAC) on machines 6 kV and above
for the main terminal box; there are no known
com-mon standards or tests for the adequacy of these
rupture discs; however, it was felt that this was a
useful start
the technology
How to Use the Standard
API 546 permits a wide range of options while still
requir-ing a reliable machine It can be used as such to specify a
synchronous motor or generator Alternatively, it can be
used with a corporate overlay that lists areas where the
par-ticular user wants something different from what is listed
in the standard It is also possible to just call up certain
sec-tions of API 546 and incorporate them into a corporate
standard However, this can cause confusion as the
corpo-rate documents written this way often have unexpected
conflicting requirements The different sections of API
546 are often interrelated to provide requirements for the
complete machine For these reasons, using only part of
API 546 is discouraged
Once the decision to purchase a synchronous motor or
generator has been made, the following are the
recom-mended ways to use the API 546 standard:
1) Decide What Is Needed: There are many choices to be
made when buying a large synchronous machine
These include power, speed, voltage, power factor,
enclosure type, cooling method, surge protection,
starting requirements, and many other issues
2) Fill Out the Data Sheets: It is essential to fill out the
purchaser’s sections of the relevant data sheets so that
the bidders know exactly what will be required of
them and will not have to make assumptions or
come back with questions during the bid preparation
In addition to the major items mentioned earlier, the
questions cover the site conditions, the load and
start-ing requirements, excitation requirements, lubrication,
efficiency cost factors, design reviews, data exchange,
and testing To help navigate the data sheets, the
data sheet guides give advice to assist with
comple-tion of the machine requirements
3) Evaluate the Manufacturers’ Responses: For both
com-petitive and single-source proposals, the
manufac-turers’ responses must be evaluated carefully to ensure
that they meet the requirements of the application
Sometimes, a manufacturer will propose an alternative
to what is specified, and this should be carefully
eval-uated In most cases, there will be some clarification
questions required before decisions can be made
4) Maintain Communication with the Manufacturer: After
the purchase decision has been made, there will still
be some questions that arise as detailed engineering
is carried out by both parties Clear communications
are necessary to ensure that the final product does
what is required of it
5) Test the Machine Thoroughly: Generally, we have found
that it helps to perform as much testing as possible
in the factory This consistently has been shown to
reduce the problems that occur during and after startup, and it is almost always faster and cheaper to solve a problem in the factory than on-site
6) Install, Start, and Run Correctly: The machine should generally be installed on a solid, flat mounting base with proper shimming and alignment by those skilled in the craft The lubrication system should
be flushed and tested to ensure that a consistent supply of clean oil reaches the bearings All the standard prestart tests, such as insulation resist-ance, should be performed and the motor pro-tection system calibrated to ensure the motor is protected After startup, the machine should be maintained in accordance with the manufacturer’s instructions, not allowed to overheat and not sub-jected to an excessive frequency of starts (in the case
of a motor)
Conclusions Synchronous machines are vital components of most process industry systems The third edition of API 546 on synchro-nous machines has been written by and for a group of experi-enced users, consultants, and manufacturers It has many enhancements in the areas where there have been concerns
in the past, so that the electrical and mechanical perform-ance and durability are improved as well as the purchasing process made easier
Acknowledgments The authors gratefully acknowledge the work done by the following members of the working group: Paul Anderson, Dennis Bogh, Mark Chisholm, Gabe D’Alleva, Gary Don-ner, Donald Dunn, Dan Eaton, Mark Fanslow, Travis Grif-fith, Mike Henry, Royce King, Horst Kuemmlee, Scott Lambie, Bill Lockley, Stefan Palmgren, Jerry Pittman, David Rains, John Rama, Rubem Ribeiro, Richard Romero, Mark Saldana, Tim Trumbo, Barry Wood, and Craig Wylie
References [1] Brushless Synchronous Machines—500 kVA and Larger, API Standard
546, 2008.
[2] IEEE Recommended Practice for Measurement of Power Factor Tip-Up of Elec-tric Machinery Stator Coil Insulation, IEEE Standard 286, 2000.
[3] Guide for a Test Procedure for the Measurement of Loss Tangent of Coils and Bars for Machine Windings, IEC 60894.
[4] IEEE Trial-Use Guide to the Measurement of Partial Discharges in Rotating Machinery, IEEE 1434.
[5] Rotating Electrical Machines Off Line Partial Discharge Measurement on the Stator Winding Insulation of Rotating Electrical Machines, IEC TS 60034-27 [6] IEEE Guide for the Evaluation of Torque Pulsations During Starting of Syn-chronous Motors, IEEE 1255.
Bill Lockley (lockley@ieee.org) is with Lockley Engineering in Calgary, Alberta, Canada Mark Chisholm is with General Electric in Pittsburgh, Pennsylvania Travis Griffith is with GE Oil & Gas in Houston, Texas Gabe D’Alleva is with Exxon-Mobil in Fairfax, Virginia Barry Wood is with Chevron in Richmond, California Lockley and Wood are Fellows of the IEEE Chisholm, Griffith, and D’Alleva are Senior Members of the IEEE This article first appeared as “API 546 3rd Edition—
Making Synchronous Machines Better” at the 2008 Petroleum and Chemical Industry Conference
19