This work was performed to develop an operational map for the objective diagnosis of the process operating states of a municipal wastewater treatment plant, for which multivariate statistical analysis techniques were applied. PCA (principal component analysis) was used to reduce the dimension of the data sets obtained from the field municipal wastewater treatment plant. A K-means clustering analysis was used to classify the group according to the property of the process operating state. A Fisher's linear discriminant analysis was used to derive the discriminant function of each classified group. An operational map was developed by scatter-plotting the derived principal components (PCs) on a two-dimensional coordinate according to the classified groups. Using the new data sets not used for developing the operational map, the practical usefulness of the operational map and discriminant function in diagnosing the process operating state were evaluated. Hence, the process operating state could be easily and quickly diagnosed and the dynamic trend of the process operating state was also able to be estimated using the operational map.

A 1MW class HTS(High-Temperature Superconducting) synchronous motor has been developed. This motor was aimed to be utilized for industrial application such as large motors operating in large plants. The HTS field windings of the developed motor is cooled by way of Neon thermosiphon mechanism and the stator coil is cooled by water through hollow copper conductor. This paper describes performance test results of our motor, which was conducted at steady state in generator mode and motor mode.

A 1 MW class superconducting synchronous rotating machine has been designed as a draft based on 2-dimensional (2D) magnetic field distribution considering several conditions such as superconducting wire length, machine efficiency, size and so on. By the way from 2D design it is not possible to consider the effect of end coils and end portions of stator iron yoke especially in superconducting machine with air-cored structure which increases magnetic field difference between 2D and 3D analysis. In this paper electrical design based on the 3D magnetic field distribution is conducted to get more proper design result and reduce design errors from 2D design approach. As the machine has larger capacity, the superconducting machine will show the advantages more and more over the conventional machine. Although the advantages at 1MW rating are not so great, the 3D design approach to get more optimized result would be very helpful for larger superconducting synchronous machine design. Through 3D analysis such as EMCN (Equivalent Magnetic Circuit Network) method and Flux-3D FEM (Finite Element Method), we could get smaller machine size, higher efficiency, and smaller Bi-2223 HTS (High Temperature Superconducting) wire length than the 2D design result. Moreover influence of an important parameter, synchronous reactance, has been analysed on the machine performances such as voltage variation and output power.

This work is development of HTS motor at DOOSAN heavy industry and Korea Electrotechnology Research Institute in Korea, and is sponsored by DAPAS program which is supported by Korean government. The final aim of the project is realization of HTS motor in the field of industry such as large driving pumps, fans and compressors for utility and industrial environments. In the first phase (2001-2004), 100 hp HTS motor was developed in order to implement the preliminary technology for the large applicable HTS motor. All of the performance characteristics are well met to the designed ones. In second phase (2004-2007), 1 MW HTS motor is developed for the purpose to fully represent the design and manufacturing issues for the larger capacity machine. The machine is 2 pole and 3600 rpm, and all of the components are completely manufactured. This machine is-now under assembly. This paper summarizes the status of 1 MW HTS motor development, such as design, construction, and experimental test results.

In large scale applications, such as SMES, motors and generators, High Temperature Superconducting (HTS) magnets are constructed with many stacks of the double-pancake coils connected in series. In spite of its higher thermal stability, HTS magnet can experience a severe quench, which can resulted from a very small portion. From HTS magnet design point of view, it is very important to predict the possibility of occurrence quench in the designed magnet to provide a suitable quench protection device. In this paper a highly instrumented HTS race track double-pancake coil was prepared to examine the quench development characteristics. It is wound using the Bi-2223 tape. Many voltage taps, cryogenic thermocouples and heater were installed in the winding. Conduction cooling method is adapted for the convenience of temperature. Quench development in the coil was measured under different operating current. The experimental details and results are presented in this paper.

On the contrary of a conventional motor with very narrow air-gap. it is difficult to calculate the accurate magnetic field distribution and the performance of an air-cored superconducting motor by 2 dimensional analysis. which does not use high permeability material except outer machine shield. This paper aims to do analysis of magnetic field and force distribution from the 3 dimensional modelling of a 1MW class superconducting synchronous motor. Especially. the field coil composed of Bi-2223 high-temperature superconductor and the outer machine shield are modelled by finite element analysis software according to their structures and the self-inductance and Lorentz force are calculated based on the 3 dimensional magnetic field calculation. Moreover. the influence of an important parameter, synchronous reactance, has been analyzed on the machine performances such as voltage variation and output power.

Synchronous reactance is an important parameter of synchronous rotating machine because it affects on the machine output capacity, voltage variation and steady-state stability. The superconducting synchronous rotating machine has very small synchronous reactance about 1/5 of the conventional synchronous machine. This reason comes from the fact that the superconducting rotating machine is air-cored structure. In this paper, it is estimated how much this synchronous reactance has influences on many design parameters of superconducting synchronous machine such as machine volume and weight, efficiency, voltage variation and so on. In the case of a synchronous motor, the power factor can be adjusted according to the excitation voltage. This paper also deals with the effects of power factor on the design parameters and the performance of a HTS (High-temperature Superconducting) synchronous motor. This kind of analysis was used to design 1 MW class HTS motor

A 3-phase, 100 hp, 4 pole, 1800 rpm superconducting synchronous motor built and tested in Korea Electrotechnology Research Institute(KERI). This machine consists of HTS rotor and air-core stator. The HTS field windings are composed of the double-pancake coils wound with AMSC's stainless steel-reinforced Bi-2223 tape conductor. These were assembled on the support structure and fixed by a bandage of glass-fiber composite. The cooling system is based on the heat transfer mechanism of the thermosyphon by using GM cryocooler as cooling source. The cold head is in contact with the condenser of a Ne-filled thermosyphon. The rotor assembly was tested independently at the stationary state and combined with stator. The open circuit, no-load, and short circuit characteristic were obtained. Also, load tests in motor mode driven by inverter and generator mode connected to resister load bank were conducted. This paper will present design, construction, and experimental test results of the 100 hp HTS machine.

Superconducting synchronous motors and generators have the field coil composed of superconductor with almost zero resistance at superconducting state. Therefore, copper loss at the conventional field coil is eliminated and the superconducting machine gets higher efficiency. The armature coil of the superconducting machine is composed of copper wire and supported by non-magnetic material such as FRP (Fiber Reinforced Plastic) This paper contains the design Procedure of a 1MW superconducting synchronous motor using high-temperature superconductor only for the field coil. Especially, the armature coil is designed by water-cooling in order to dissipate Joule heat easily. Moreover, 3-dimensional electromagnetic design is conducted to get a proper design result and reduce design errors from 2-dimensional approach.

A 1 MW class superconducting synchronous motor is designed considering several conditions such as superconducting wire length, machine efficiency and size. As the machine is larger and larger, the superconducting machine shows the advantages more and more over the conventional machines. Although the advantages at 1 MW rating are not so great, the design approach to get an appropriate result would be very helpful for larger superconducting synchronous machine design. Major design concerns are focused on reducing expensive Bi-2223 HTS (High Temperature Superconducting) wire which is used for superconducting field coil carrying the rating current around 30 K (-243/spl deg/C) while the machine efficiency is higher than conventional motors or generators with the same rating. Furthermore, some iron-cored structure is considered to reduce the HTS wire requirement without bad effect on machine performances such as sinusoidal armature voltage waveform, synchronous reactance and so on.

A superconducting motor consisting of high temperature superconducting (HTS) rotor and air-core stator is under development in Korea Electrotechnology Research Institute. HTS motor was designed for having the rated power of 100 HP at 1800 rpm. HTS field winding is composed of sixteen HTS race track shaped coils wound with stainless steel-reinforced Bi-2223 tape conductor by react and wind fabrication method. Nomex paper was used for electrical insulation. Each of four field coil assemblies was constructed with four double pancake sub-coils, mechanically stacked and electrically connected in series. Four field coil assemblies were fixed on an aluminum support structure to make effective heat transfer. Voltage terminals were attached to both ends of joints to measure joint resistances. HTS field winding was tested at 77 K, and the Joule heats generated at all the joints was calculated. In this paper, design, construction and testing of HTS field winding, Joule heat generated by the joints, and operating current were discussed.

This paper describes the development and fabrication of a high temperature superconducting motor which consists of HTS rotor and air-core stator. The machine was designed for the rated power of 100hp at 1800 rpm. The HTS field windings are composed of the double-pancake coils wound with AMSC's SUS-reinforced Bi-2223 tape conductor. These were assembled on the support structure and fixed by a bandage of glass-fiber composite. The cooling system is based on the heat transfer mechanism of the thermosyphon by using GM cryocooler as cooling source. The cold head is in contact with the condenser of a Ne-filled thermosyphon. The rotor assembly was tested independently at the stationary state and combined with stator. Characteristic parameters such as reactances, inductances, and time constants were determined to obtain a consistent overview of the machine operation properties. This motor has met all design parameters by demonstrating HTS field winding, cryogenic refrigeration systems and an air-core armature winding cooled with air. The HTS field winding could be cooled down below 30K. No-load test of open-circuit characteristics(OCC) and short-circuit characteristics(SCC) and load test with resistive load bank were conducted in generator mode. Maximum operating current of field winding at 30K was 120A. From OCC and SCC test results synchronous inductance and synchronous reactance were 2.4mH, 0.49pu, respectively. Efficiency of this HTS machine was 93.3% in full load(100hp) test. This paper will present design, construction, and basic experimental test results of the 100hp HTS machine.

A 100 HP rated synchronous motor with superconducting rotating field winding has been designed based on the formulated equations established from 2 dimensional magnetic field distributions in a cylindrical coordinate. The cross-section was drawn based on calculated design results via Fortran program and then modeled with FEM (Finite Element Method) to investigate the machine performances. First of all, the magnetic field distributions are analyzed in many ways according to the field directions and the armature currents. Especially after the rotating field winding is arranged with BSCCO-2223 high-temperature superconducting (HTS) pancake coils, the exerted magnetic field normally on the HTS tape is calculated through FEM. And the machine output power is calculated according to the torque angles that lie between the field and the armature main flux lines. Moreover, this paper includes the eddy-current loss variations of a copper damper located between the field and the armature coils. Finally, 3 dimensional magnetic field distribution is also calculated via FEM. The radial components of magnetic field are compared along the center line of an armature conductor section between 2 dimensional and 3 dimensional results. By the comparison we make sure that about 30% of machine output is added from the end effect of HTS field coil and more accurate design approach is possible.

1MW class superconducting synchronous motor is designed considering several conditions such as superconducting wire length, machine efficiency and size. As the machine is larger and larger, the superconducting machine shows the advantages more and more over the conventional machines. Although the advantages at 1MW rating are not so great, the design approach to get an appropriate result would be very helpful for larger superconducting synchronous machine design. Major design concerns are focused on reducing expensive Bi-2223 HTS(High Temperature Superconducting) wire which is used for superconducting field coil carrying the rating current around 30K(-243) while the machine efficiency is higher than conventional motors or generators with the same rating. Furthermore, some iron cored structure is considered to reduce the HTS wire requirement without bad effect on machine performances such as sinusoidal armature voltage waveform, synchronous reactance and so on.

This study discusses an analytical model for evaluating and measuring the tappet rotational speed of the direct acting valve train system. To calculate the tappet rotational speed, the load transferred to the cam and the tappet is calculated using dynamic analysis of a single valve system. The friction against the cam and tappet is calculated using mixed lubrication theory while considering the both of oil film and friction between tappet and tappet bore at the same time. A dynamic equation is developed for the rotational and translational motion of tappet within the tappet bore, and the solution of the equation obtained using numerical method. We have developed a rotational speed signal monitoring system using a laser and optical fibre to measure the tappet rotational speed. To measure the tappet rotational speed the system uses on/off signals from the encoder and a photo transistor attached under the tappet. We discuss several analyses and experiments executed under various operating conditions and compare to each other. Analytical and experimental results are generally coincided with each other. The rotational speed of the tappet tends to increase with eccentricity and temperature of the supplied oil. Also it tends to increase with the earn rotational speed as well. This study shows also that tappet rotation reduces the friction loss between the cam and the tappet.

This study discusses the effects of crankshaft offsets to the piston thrust side on engine friction. An analytical model to interpret some key friction parts of an engine, such as crankshaft bearings. pistons and piston rings, is considered, and the effects of a crankshaft offset on the moving parts is calculated using numerical analysis. Analytical results show that the crankshaft offset has some influence mainly on the side force upon the piston and effects variation in the piston sliding speed. The crankshaft offset can reduce significantly friction loss of the piston skirt, whereas friction loss in other parts is negligible. The optimum offset to minimize skirt friction loss depends on the operating conditions. Upon calculation and measurement it is determined that reduction in friction loss occurs mainly at low engine speed and low engine load. When the speed and load increase, benefit is confined to the lowest offsets, and at higher offsets the friction increases. Analytical and experimental results indicate that crank offset is effective in reducing engine friction and improving fuel economy in the low and medium engine speed region.