Instructional overview of IEEE 1349-2001-guide for the application of electric motors in class I, division 2 hazardous (classified) locations

This work presents an overview of IEEE 1349-2001, a Guide that assists individuals, organizations, and suppliers with the application of motors in Class I, Division 2 locations, where flammable gases and vapors may occasionally be present. Three-phase and single-phase ac synchronous and induction electric motors in sizes from fractional horsepower through 10 000 hp and beyond are covered in the Guide. Primary emphasis is on the use of general-purpose enclosures and precautions against excessive surface temperatures and sparking of rotor bars and enclosure joints. The Guide also provides guidance for maintaining the life-cycle integrity of motors in Division 2 locations. Existing codes and standards, such as the National Electrical Code, contain cautionary notes for general-purpose motor applications in Division 2 areas. This Guide documents industry experience and established practices for the application of general-purpose motors in Division 2 locations and provides guidance for applying motors in these locations. It is not a specification and is not intended to be used as a specification for purchasing motors installed in Division 2 locations. This paper does not replace the Guide, but should be used to supplement and understand the Guide. Significant motor temperature information is contained in the Guide including maximum recommended Division 2 exposed surface temperatures at full load. Manufacturers, users, and other industry experts worked about eight years to develop this consensus standard. It was approved by the IEEE-SA Standards Board in December 2001 and published in June 2002.     

Reliability comparison between standard and energy efficient motors

There are always tradeoffs when maximizing a specific motor performance parameter such as efficiency. The purpose of this paper is to compare the various performance parameters and elements which determine motor reliability. The impact on motor life is considered, along with its robustness. Only the three-phase squirrel-cage induction motors covered by the 1992 Energy Act are covered in this presentation, as compared to “standard” motors     

Comparison testing of IEEE standard 841 motors

The IEEE Standard 841 was developed to identify additional specific features deemed necessary for application of induction motors in the petroleum and chemical industry. The Pulp and Paper Industry Committee (PPIC) of the IEEE Industry Applications Society has also been studying the IEEE Standard 841 for possible adoption by the pulp and paper industry. Members of the PPIC Ad Hoc Committee on IEEE 841 have suggested additional requirements to those in the existing standard. This paper discusses a comparison testing program conducted by the Motor Systems Resource Facility, an EPRI/BPA center at Oregon State University, Corvallis, in support of an industrial investigation of the available motors manufactured to the IEEE Standard 841. Seven major motor manufacturers participated in this study. Each manufacturer provided a 50-hp, a 100-hp, and a 200-hp "Standard" IEEE 841 motor for examination on delivery and IEEE 112 Method A efficiency testing. All of the motors were horizontal, three phase, 60 Hz, four pole, and 460 V (except one that was 575 V)     

Application of Permanent Magnet DC Motors at Republic Steel's 84-in Hot Strip Mill

Modern magnetic materials of the Alnico? type have made it practical to build dc motors in larger sizes with permanent magnet fields. The motor manufacturers now market motors to 100 hp at 230-V dc with dimensions, speeds, horsepower ratings, and other characteristics equivalent to the Association of Iron and Steel Engineers (AISE) Standard Mill Type Motors. Previously, smaller motors of this type have come into common usage as table motors. The first large-scale industrial application of these larger motors was at Republic Steel's 84-in hot strip mill in Cleveland, Ohio. This paper reviews the application of these motors on this mill. It discusses application limitations based on design characteristics, the economics of their use, and their performance and service.     

Induction Motor Efficiency Test Methods

Electric motor drives are significant to the overall energy requirements of the country and the world. The majority of these electric motors are squirrel cage induction motors, and it is to the efficiency testing of these motors that this paper is directed. It is essential that motor efficiencies be determined accurately to allow true comparisons to be made between alternate offerings and to assess correctly the motor's share of system energy consumption. IEEE Standard 112, the recognized test procedure in the United States, has recently been revised. This paper presents the revised methods and compares this Test Procedure with IEC 34-2 and JEC-37. Each of these specifications includes a variety of basic methods for determining efficiency based on motor size and availability of test equipment. The National Electrical Manufacturers' Association has recommended the use of IEEE Standard 112, Method B for ac motors of 1-125 hp. Ranking of different methods in order of desirability and practicality of use is presented.     

Flammable vapor ignition initiated by hot rotor surfaces within aninduction motor: reality or not?

This paper tests the validity of the American Petroleum Institute (API) publication's premise as applied to flammable vapor ignition on hot surfaces within an induction motor. Several motors of various sizes are instrumented with thermocouples, a flammable concentration of a material of low autoignition temperature (AIT) (e.g., diethyl ether, n-hexane, n-heptane, or tetrafluoroethylene) is introduced to the motor interior, and the motors are subjected to a series of short-duration locked-rotor tests where the rotor surface temperature is brought, in defined increasing steps, above the material's listed AIT. The temperatures at which ignition occurred are reported. These tests are intended to simulate the condition of a fully loaded motor being suddenly stopped in an atmosphere of flammable gas or vapor, such as during an emergency shutdown of a processing unit during a release. Other tests were conducted on running motors at overload to heat the rotor well above normal operating temperature to simulate somewhat abnormal operating conditions. The results of the tests provide data for the IEEE P1349 Working Group's effort and lead to some significant conclusions for the application of induction motors in classified locations     

Increased Efficiency Versus Increased Reliability

The vast majority of totally enclosed fan cooled (TEFC) squirrel cage induction motors in the 1-to 20-hp range installed in the petroleum and chemical industries are National Electrical Manufacturers Association (NEMA) "T" frames built prior to 1992, NEMA "T" frames built in accordance with the Energy Policy Act of 1992 (commonly referred to as EPAct motors), and the NEMA Premium motors, introduced after the year 2000, that exceed the EPAct efficiency standards. All three types are available in accordance with the IEEE 841 recommended practice and standards. The most obvious difference in these three generations of motors is their efficiency levels. There has been some concern expressed by the users of these motors that to achieve the premium levels of efficiency it was necessary to compromise other performance characteristics and the motor reliability. This article addresses these claims and shows that they are without basis.     

Surface Temperature Test Methods Per IEEE 1349

The fine print note (FPN) No. 1 in 2005 National Electrical Code (NEC) Article 501.8 (B) [ANSI/NFPA 70, National Electrical Code, 2005 (NEC)] cautions users to "consider the temperature of internal and external surfaces that may be exposed to the flammable atmosphere" when putting a motor into service in a Class I, Division 2 environment. Thus, it is critical that manufacturers and users of industrial electric motors understand that internal peak temperatures exceed the external peak temperatures. This paper presents three common IEEE 1349 [IEEE 1349-2001, IEEE Guide for the Application of Electric Motors in Class I, Division 2 Hazardous (Classified) Locations] test methods used by manufacturers to determine these internal peak temperatures. Potential test method error and the test results from the three test methods are also presented. IEEE 1349 provides only guidance when performing these test methods so this paper intends to provide additional clarification. The test motors presented in this paper are low voltage, ac induction, severe-duty, energy-efficient, totally enclosed fan-cooled motors commonly used in the "Petrochemical Industry."     

Introduction to IEEE 841-2001, IEEE standard for petroleum and chemical industry-severe duty totally enclosed fan-cooled (TEFC) squirrel-cage induction motors-up to and including 370 KW (500 HP)

IEEE 841-1994, IEEE Standard for Petroleum and Chemical Industry Severe Duty Totally Enclosed Fan-Cooled (TEFC) Squirrel-Cage Induction Motors-Up to and Including 500 hp, issued in 1994, has been updated and improved. The scope includes three-phase severe duty TEFC squirrel-cage induction motors with antifriction bearings in sizes up to and including 370 kW (500 hp) and motor rated voltages of 200, 230, 460, 575, 2300, and 4000 V at 60 Hz. Changes to the standard are reviewed in detail. Requirements are identified that improve motor reliability and increase motor life.     

Recent important changes in IEEE motor and generator winding insulation diagnostic testing standards

IEEE standards and test procedures are widely used by motor and generator vendors and users to commission windings in new machines, as well as evaluate the condition of the winding insulation in operating machines. Until recent revisions, the basic procedures and standards in use were written over 25 years ago. Since the 1970s, motor windings have encountered many changes in their design and manufacture. The result was that the interpretation of results in many of the standards was no longer valid for the more modern motors. Over the past five years, the IEEE Power Engineering Society has conducted a major review and updating of most of these standards. Many important changes in test procedures and interpretation guidelines have resulted. This paper reviews the main insulation standards used for stator and rotor winding diagnostic testing, and discusses the changes that have been made. Standards discussed include: IEEE 43, 56, 95, 286, 522, and 1434. For example, IEEE 43-2000 now requires a minimum insulation resistance of 100 M/spl Omega/ for new stator windings rated 2300 V or more, rather than the "kV+1" that was required in the past. Furthermore, the interpretation for polarization index has changed such that a motor with a polarization index of 1 is no longer automatically classed as bad.     

No tooling cost process for induction motors energy efficiency improvements

In this paper, the analysis of some possibilities for increasing the induction motor efficiency using production technological process modifications is reported. This approach is known as the "no tooling cost" (NTC) strategy because it does not require a complete redesign of new laminations with a consistent cost in terms of investments. The paper shows the results obtained by a full experimental approach, using "ad hoc" prototypes. The NTC design modification and the technological processes analyzed in this paper have been done on totally enclosed fan-cooled standard induction motors. Obviously, the original motors have been compared from the energetic point of view with these prototypes. The energetic performance has been measured in accordance with the IEEE Std. 112-96 Method B. In particular, the following modifications, for obtaining an increase in efficiency, have been taken into consideration: rotor with copper bar included in the slot before the aluminum die cast, increase of the core axial length, and annealing of the stator core.     

Automated Motor Testing Using a Minicomputer

A new approach to rapid automated performance testing of motors is presented in this paper. Specific application is made to brush motors (such as those used in vacuum cleaners) in order to illustrate the techniques on a motor which, because of its high speed and heating characteristics, is considered to be more difficult to test than other types of motors. The application of the technology described in this paper to other types of motors is straightforward.     

Petrochemical AC induction motor standards

This article discusses the IEEE 841-2001, API 541 4th edition, and API 547 standards for AC induction motor developed by the petrochemical industry. This article will help to identify which of the three standards are most appropriate for a particular application and a detailed comparison of the three standards are presented. All three standards provide specific and verifiable requirement that enable a user to purchase motors for most applications that will yield increased reliability over standard or severe duty motors.     

安萨尔多的电机与国内电机区别

随着我国科技不断发展进步,电机技术日益成熟,很多电机逐步由进口转为国内产品所代替,但仍有部分电机是从国外进口。以一台意大利安萨尔多YB 800-6p 2000kW电机为例,通过技术分析介绍其结构特点,并与国内相同电机的结构进行比较,分析出其结构的优点。     

Temperature effects on torque production and efficiency of PMmotors using NdFeB magnets

Recent developments in high energy magnets have created widespread interest in the area of permanent magnet (PM) motors. The use of PM synchronous motors or brushless motors to replace conventional DC or induction type motors has not been as speedy as anticipated earlier. This paper deals with the temperature effects of PM motors using neodymium magnets on the torque production capability and on the efficiency of the motor. When PM motors are designed to operate in a wide temperature range, the reversible demagnetization of the neodymium magnets with temperature and the increase in winding resistance with temperature influence the maximum torque capability at rated speed and efficiency of the PM motor. The maximum torque at rated speed is limited due to the fixed DC link voltage of the inverter feeding the motor. In this paper, it is shown that over an operating range of -40°C to 150°C the maximum torque capability and efficiency of the motor can vary over a wide range. It is also shown that for certain designs, a near flat maximum torque versus temperature characteristic may be obtained. The major factors influencing these variations are identified. The discussion in this paper is concentrated on PM motors with a trapezoidal back EMF waveform. The idea could be extended to sinusoidal back EMF motors and to PM DC motors     

IEEE 841 motor vibration

This article reviews the physics that cause vibration in three-phase motors and suggest methods to reduce vibration. There are two major causes of vibration in IEEE 841 motor. Unbalance vibration at IX rotational speed, vibration due to magnetic forces. Vibration in an installed motor system can be caused by numerous variables. This vibration is the result of rotor and stator forces on the bearings acting with in the system. Final attempt are made to quantify the cost of motor vibration in terms of equipment life.     

International standards for the induction motor efficiency evaluation: a critical analysis of the stray-load loss determination

Motor efficiency has to be measured or calculated in accordance with international standards. The most important standards are the IEEE 112-B, IEC 34-2, and JEC 3 . In this paper, a comparison of the measurement procedures defined by these international standards is reported, together with some comments on the prescribed methodologies. The comparison is based on experimental results obtained by tests on four general-purpose three-phase induction motors. The stray-load loss measurement represents a critical key for the correct evaluation of the motor efficiency. For this reason, a critical analysis of this type of losses has been performed. In particular, in order to understand which are the most critical quantities that influence their evaluation, the stray-load loss sensitivity to the measurement errors is analyzed. In the final part of the paper the temperature influence, on the conventional iron losses, is experimentally analyzed. The performed tests show that the temperature difference between the no-load test and the motor real operative conditions is not negligible.     

Introduction to IEEE 841-1994, IEEE standard for petroleum andchemical industry-Severe duty totally enclosed fan-cooled (TEFC)squirrel cage induction motors-up to and including 500 hp

IEEE 841, Recommended Practice for Chemical Industry Severe Duty Squirrel-Cage Induction Motors-600 V and Below, first issued in 1986, has been significantly revised and reissued as a Standard. The scope has been increased to include severe duty TEFC squirrel-cage induction motors with antifriction bearings in sizes up to and including 500 horsepower. Motor rated voltages of 2300 V and 4000 V have been added. Changes to the standard are reviewed in detail. Requirements are identified that improve motor reliability and increase motor life     

A Nonintrusive and In-Service Motor-Efficiency Estimation Method Using Air-Gap Torque With Considerations of Condition Monitoring

Energy usage evaluation and condition monitoring for electric machines are important in industry for overall energy savings. They are often expected to be implemented in an integrated product because of many common requirements such as data collection. Because of the uninterrupted characteristic of industrial processes, traditional methods defined in IEEE Standard 112 cannot be used for these in-service motors. This paper proposes a truly nonintrusive method for in-service motor-efficiency estimation based on air-gap torque using only motor terminal quantities and nameplate information, with special considerations of motor condition monitoring requirements. Rotor speed and stator resistance, the stumbling blocks of most in-service testing methods, are extracted from motor input currents instead of being measured. The no-load test, which is required for calculating the rotational loss and core loss, is eliminated by using empirical values. Stray-load loss is assumed according to the motor horsepower as suggested in IEEE Standard 112. Finally, the proposed method is validated by testing three induction motors with different configurations. Experimental results show that the proposed method can estimate motor efficiencies with less than 2% errors under normal load conditions.      

Failure identification and analysis for high-voltage inductionmotors in the petrochemical industry

This paper gives a synopsis of condition monitoring methods, both as a diagnostic tool and as a technique for failure identification in high-voltage induction motors in industry. New operating experience data for 483 motor units consisting of 6135 unit years are registered and processed statistically to ascertain the connection between motor data, protection and condition monitoring methods, maintenance philosophy and different types of failures. The different types of failures are further analyzed to determine the failure initiators, contributors and underlying causes. The results have been compared with those of a previous survey, the “IEEE Report of Large Motor Reliability Survey of Industrial and Commercial Installations, 1985.” In the present survey, the motors range from 100 to 1300 kW; 47% of them are between 100-500 kW