This article presents the application of the constant Volts per Hertz control to control a three phase induction motor has torque and speed characteristics similar to wind turbine. Due to this method is not complicated and does not require the parameters of motor. As a result the accuracy of control is independent of variation of the parameters of motor. Furthermore the equation for compensate the difference between the moment of inertia of wind turbine and motor which is consistent with the mentioned control method is proposed. In order to make the dynamic responses of the wind turbine simulator similar to the wind turbine and to overcome the problems of noise amplification from differentiation that leads to instability of the system. The simulation results in Matlab/Simulink program show that the proposed wind turbine simulator can imitate the wind turbine accurately both in dynamic and steady state conditions

The objectives of this research are to analyze the relationship between securities price and the efficiency of the account receivable management and to study the model of improving the efficiency of the account receivable management of the agricultural business group in the Stock Exchange of Thailand. The number of data which had been used in this research was 16 random companies of all 22 companies from the listed companies in the Stock Exchange of Thailand agricultural business group by using purposive sampling method. The researcher used both quantitative and descriptive analysis method by bringing the quantitative data analysis from 2006-2010 to descriptive analyzing which had compared between the selling revenue account receivable value allowance for doubtful bad debt account receivable turnover average collection period book value per share primary earnings per share and securities price. The results of analyzing are changing in the account receivable of Chiangmai Frozen Foods Pcl. Lee Pattana Pcl.; changing in the bad debt of Pak Food Pcl.; changing in the average collection period of Thai Rubber Latex Corporation (Thailand) Pcl. Pak Food Pcl.; changing in the book value per share of Pak Food Pcl. Kiang Huat Sea Gull Trading Frozen Food Asian Seafoods Pcl. Asian Seafoods Pcl.; changing in the primary earnings per share of Thai Rubber Latex Corporation (Thailand) Pcl. Thai Luxe Enterprise Pcl. Lee Pattana Pcl. and Kiang Huat Sea Gull Trading Frozen Food Asian Seafoods had related to securities price per share.

This research presents the design and construction of molten brass to form the basis of induction heating. It is heated by the half-bridge voltage source in series resonant load by transferring the heat energy through the graphite crucible for 300 grams melting of the brass in 10 minutes. The system is controlled to operate at a higher frequency than the resonance frequency mode with the input three-phase AC voltage 380 V 50 Hz through a rectifier into a DC voltage to be supplied to the inverter supply voltage half-bridge about 35 kHz switching frequency at the rated power 4.5 kW