Totally Enclosed Fan Cooled Research Articles

Motor temperature considerations for pulp and paper mill applications

This paper reviews the motor temperature operating consideration for totally enclosed fan cooled (TEFC), open dripproof and weather protected II type of motor through 500 hp, both low voltage (LV) and medium voltage (MV). The IEEE Standard 841 has been revised as IEEE Std 841-2001 and is expected to be in use for at least five years. The TEFC motors covered in this standard have found wide acceptance in the pulp and paper industry. Much of the material also applies to large motors sizes. The thermal impact on the stator winding rotor core, bearings, and lubrications as specified in standards and applied in mills are considered.

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.

Evaluation of maximum rotor temperatures in TEFC inverter-fed motors

Based on the need to provide clearer application guidelines for motors supplied from adjustable-speed drives in Class I, Division 2 areas, the authors decided to conduct a test program to investigate the impact of adjustable-speed drives on totally-enclosed fan-cooled (TEFC) motor rotor temperatures. Hopefully, the results of these tests will foster industry discussion and increase collaboration among users and manufacturers.

An Interactive Software for the Analysis of Thermal Characteristics of Capacitor-Run Single-Phase Induction Motors

This paper reports on the development of a software package, in FORTRAN 90, for determination of thermal characteristics of a capacitor-run single-phase induction motor. The software can be used for (i) calculating the steady-state temperature of the body and any internal part of the motor structure, (ii) heating and cooling curves at no load, and (iii) transient thermal characteristics for surface and stator slot temperatures at different loading. For normal motor operation, the steady-state temperature rise can be used as a direct measure of loss rather than the small difference between input and output power. In the software, the design details of the motor have been used as the input data, and a mixed-parameter thermal model has been developed based on dimensional information and constant thermal coeffi cients. The thermal model developed by the authors has been tested with a 3.5-HP, 400-V, 50-Hz capacitor run totally enclosed fan cooled (TEFC) single-phase motor. Its performance has been found to be in conformity with experimental temperature data for the body and the conductors inside the slot of the motor, obtained by varying the load for different values of the run capacitance. A computer-aided data acquisition system has also been developed for the on-line temperature monitoring of the stator slot. The conductor temperature also has been estimated by resistance method.

Heat transfer enhancement of finless TEFC induction motor frame by installing guide vanes

The heat generated in an induction motor is mostly dissipated through the frame. The study on the heat transfer characteristics of a newly manufactured finless TEFC(Totally Enclosed Fan Cooled) induction motor showed/that it had an unsuitable structure in view of the heat transfer. The angle of the cooling air flow was very large and the ribs disturbed the air flow and partially generated the wake region on the frame. In the wake region the temperature was very high. Thus the heat transfer coefficients were lower than those of the frame with fins. Also was investigated the heat transfer characteristics of the motor frame by installing various guide vanes in the fan-side end cap. An optimum heat transfer case was found and the average heat transfer coefficient of the frame was 70% higher and the average coil temperature measured by the resistance method was 9 deg. C lower than that of the frame which had no guide vanes.

THERMAL MODEL FOR A SWITCHED RELUCTANCE MOTOR OF TEFC DESIGN DURING STEADY AND TRANSIENT OPERATION

A lumped-parameter approach is adapted for the prediction of the steady-state and transient thermal behaviour of a prototype multiple teeth per stator pole switched reluctance motor (SRM), of TEFC (Totally Enclosed fan-cooled) design as an illustrative example. The merit of the method has been demonstrated by its application to the induction motor and experimental verification. The SRM is subdivided into simple geometries and the equivalent circuits and the proper connection of these equivalent circuits are presented. The combination of these circuits forms the full model which is used for prediction of the temperature rise of different parts of the motor.

Introduction to 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

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.

In-situ determination of thermal coefficients for electrical machines

A method for determining the thermal coefficients in electrical machines based upon a new linear lumped parameter model and accurate measurement of temperature and loss densities within the machine is presented. The thermal network is reduced to a system of simultaneous equations. The equivalent thermal coefficients are determined by solving the equations using a singular value decomposition (SVD) method. Results obtained for a 4 kW totally enclosed fan cooled (TEFC) induction motor are presented and compared with established data. The technique is suitable for establishing more accurate thermal coefficients for composite materials and combinations of complex geometrical form. >