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Motors are critical components for electric utilities and process industries. A motor failure can result in the shutdown of a generating unit or production line, or require that redundant plant be utilized to circumvent the problem. One major cause of failures is breakdown of the tum insulation leading to puncture of the groundwall. Early detection of intertum shorts during motor operation would eliminate consequential damage to adjacent coils and the stator core reducing repair costs and motor outage time. In addition to the benefits gained from early detection of tum insulation breakdown, signijicant advantages would accrue by locating the faulted coil within the stator winding. Fault location would not only increase the speed of the repair, but would also permit more optimal scheduling of the repair outage. This work was successful in practically implementing a theory to predict changes in the axial kakage flux resulting from stator winding intertum shorts and in developing an algorithm to locate the position of the faulted coil. An experimental setup consisting of a 200 hp motor loaded by a generator was used to validate this theory. Suitable transducers were developed and installed on this motor. Measurement using this experimental configuration clearly validated the theoretical model. On the basis of this experimental work, an instrument to continuously monitor for shorted turns is under development.

The paper describes a method for the dynamic simulation of dynamic rotor eccentricity in squirrel cage rotor induction machines. The method is based on a winding function approach, which allows for all harmonics of magnetomotive force to be taken into account. It is demonstrated how this complex dynamic regime can be modeled using the mutual inductance curves of symmetrical machine using proper scaling techniques. Experimental results demonstrate the effectiveness of the proposed technique and validate the theoretical analysis.

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The observed dynamic thermal response of intermittently occupied buildings can usually be described by one or two time constants. This suggests that much of the complexity in detailed computer thermal response models may not always be necessary. Simplified thermal response models may be adequate for many purposes, and ought to have cost advantages, both in setting up and run time. The paper describes the basis of a simplified microcomputer model of building thermal response. Model predictions of internal temperature variation in a working school are shown to agree well with observations. The model is intended for professional use and user interface is being developed in consultation with an architectural practice.

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