At nuclear power plants, electrical valve actuators are important for ensuring that the reactor core is water covered and the pressure in the reactor tank and containment is limited. The electrical actuators are provided with overload protection in case of drawing higher current then the motors are rated for. When safety manoeuvres are needed, the overload protection must not trig and cause the valve to stop before completing the manoeuvre. Analyses have showed that the current settings of the overload protection may cause an illegitimate trig at the worst theoretically possible accident. A new method has been developed with conservative assumptions and applies overload protections for all electrical valve actuators at the three reactors in Forsmark.

The purpose of this research was to determine the extent to which parents and professionals were in agreement prior to and following intervention regarding their Judgement of the gross motor abilities of the parents' preschool children. Each child was tested by a professional on the Ulrich Test of Gross Motor Development (1985). Dependent measures were parents' perceptions (N = 28 pairs) of their children's gross motor abilities. Parents were randomly assigned to either an intervention (treatment) or non-intervention (control) group. The intervention period included two-ninety minute videotaped observational training sessions, on how to observe gross motor patterns in a young child, over a two-week period. At the conclusion of the intervention period, all parents completed a questionnaire similar to one completed prior to intervention. Both questionnaires provided information on parents' perceptions of their children's gross motor abilities. Paired-t tests were used to determine if significant differences existed between parents and professionals prior to intervention. Paired-t tests were also used following observational training intervention to analyze any changes over time between the pre-intervention and post-intervention periods for intervention and nonintervention parents. Student-t tests were used to compare post-intervention differences between intervention parents and nonintervention parents. An alpha level of .10 was used in this study. The results of the study revealed a significant difference between parents' perceptions and professional assessments. Most parents tended to overestimate their children's gross motor abilities relative to the professional standard. Significant differences were reported for changes occurring over time between the pre-intervention and post-intervention periods. Significant differences also were found between groups following intervention. Parents receiving observational training demonstrated more realistic perceptions of their children's gross motor abilities relative to professional assessments than did parents not receiving observational training. As a result of these investigations, it was determined that parents and professionals were generally not in agreement with respect to children's current level of functioning in gross motor abilities. Parents, as previous literature has described, also tended to overestimate their children's abilities. Furthermore, the introduction of an intervention program, which trained parents to become better evaluators of motor ability, resulted in positively influencing parents' perceptions of their children's gross motor abilities. / Graduation date: 1990

In preliminary building energy assessments, it is often desired to estimate a motor's input power. Motor power estimates in this context should be rapid, safe, and noninvasive. Existing methods for motor input power estimation, such as direct measurement (wattmeter), Current Method, and Slip Method were evaluated. If installed equipment displays input power or average current, then using such readings are preferred. If installed equipment does not display input power or current, the application of wattmeters or current clamps is too time-consuming and invasive for the preliminary energy audit. In that case, if a shaft speed measurement is readily available, then the Slip Method is a satisfactory method for estimating motor input power. An analysis of performance data for 459 motors suggests comparable performance for predicting normalized (to the nominal motor input power) motor input power with the Current and Slip Methods: 10.0% and 9.9% RMSE, respectively. Both of these methods may be improved by applying regression on the predicted variable and/or nameplate parameters. For example, the Slip Method could be improved by applying a second-order regression, thereby reducing the predicted load factor residual RMSE of the data set from 9.0% to 8.2%. The Current and Slip Methods were also evaluated on two real motors. The normalized (to the nominal motor input power) predicted input power RMSE for the Current Method was on average 15% for the two motors; for the Slip Method the corresponding average was 17.5%. In some cases, shaft speed measurements may not be available. A temperature-based approach for estimating motor input power was investigated. Other required parameters include ambient temperature, motor efficiency, and a motor thermal constant. The temperature approach offers quick, safe, and non-invasive motor power estimation. However, thermal coefficients may vary significantly across motors and a model to predict the thermal coefficients has yet to be developed. Furthermore, the temperature approach has a very strong dependence on motor efficiency uncertainty. Experiments were performed on two motors to determine their motor thermal constants. If a motor's thermal constants and running efficiency are known, then this method gave motor input power estimates with a RMSE (normalized to the nominal input power) on the order of 4% for the studied motors.

This research proposes the architecture of motor driver IC for the application of small BLDC motors. Both analog and digital mixed-mode techniques are employed here to design BLDC fan motor driver IC. The controlling method of this motor driver IC mainly utilizes analog approach. Besides, in order to prevent any damages on motors due to abnormal operations, digital control circuit is also involved in this IC. This motor driver IC is used in heat-sinking fan on notebooks as well as on the motors with very small impedance, so the IC is designed to be able to work in low supply voltage, and has high driving capability at the output stage. Via the feedback signal generated by the Hall sensor, it controls the motor driver IC so that the IC can supply current accordingly to stator coil. Therefore, the purpose of controlling motors is then achieved.

The TI TMS320LF2407A DSP is used as the control kernel in this thesis, proposing a method of sensorless control for the brushless DC motor. With six-step pulse-width modulation, the information of the back electromagnetic signals can be detected and is used to estimate the rotor position instead of the Hall sensors. To strengthen the system and reduce the power consumption, we propose the idea of close loop framework, including speed feedback and current feedback. Then, the phase-change signal is set as no delayed, 15 degree delayed, and 30 degree delayed and compare the results each other. Finally, setting up experimental framework, to verify the superiority of sensorless drivers with close-loop framework, and choosing better phase-change degree to improve system and efficiency.

<p>This thesis deals with the integral motor of tomorrow, and particularly with a variable speed, sensorless permanent magnet synchronous motor with an integrated converter. The rated power is 15 kW at 1500 r/min. The outer dimensions are approximately the same as for the equivalent standard induction motor.</p><p>Control strategies for pumps and fans, i.e. suitable loads for variable speed motors, are briefly described. The huge energy savings that can be made by reducing the speed instead of throttling/choking the flow are pointed out. Compared to installing an induction motor with a separate converter, a PM integral motor will probably pay-off in less than a year.</p><p>A <i>totally analytical</i> expression for calculating the airgap flux density of permanent magnet motors with buried magnets is derived. The analytical expression includes axial leakage, and iron saturation of the most narrow part of the magnetic circuit of the machine.</p><p>A computer program for optimization of PM motors with buried magnets has been developed. It was used to design the manufactured prototype PM integral motor, and the parameters are investigated with analytical and/or FEM calculations. The optimization program is also used to suggest nearoptimum pole numbers for desired powers (4-37 kW) and speeds (750- 3000 r/min) of inverter-fed PM motors. Results show that compact buried PM motors should have relatively large airgaps and high NdFeB-magnet masses to improve the efficiency. Ferrite magnets are unsuitable.</p><p>Measurements on the manufactured PM motor, the novel concept of stator integrated filter coils, and the complete PM integral motor are presented. Special attention was given to temperature and overall efficiency measurements.</p><p>The rotor cage losses were investigated by time-stepping FEM. Four short circuit fault conditions were also examined in order to evaluate the risks of demagnetization of the buried magnets. </p>

Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains xv, 198 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 165-177).

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Toxicology." Includes bibliographical references (p. 148-167).

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xi, 133 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 129-133).

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xviii, 100 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 98-100).