Analysis and design of stator terminals reversal connection detector for Synchro-to-Digital converter
In this paper, a stator terminals reversal connection detector is presented for Synchro-to-Digital Converter (SDC). This is useful for identifying inadvertent reversal connection of synchro output signals to SDC. Synchro is a positional sensor excited by a sinusoidal signal and gives three electrical signals. The zero crossing outputs of synchro and a clock based on synchro excitation signal are generated. Then the phase relationship between excitation and synchro output signals is analyzed for possible stator terminal reversal connections between synchro and SDC. This method uses simple electronic components such as operational amplifiers, monoshots and flip flops. The analysis, implementation and experimental results are presented.
Modelling and simulation of synchro and synchro-to-digital converter for electrical motor drives
In this study, modelling and simulation of synchro and synchro-to-digital converter (SDC) are presented. This study is useful to estimate the shaft position and speed of induction motor using SDC through a synchro. The SDC uses scott-T circuit to convert three signals of synchro into two signals format. The position information of synchro shaft is present in peak amplitudes of scott-T outputs. A demodulator circuit is designed to extract the peak amplitude levels. The quadrant in which the shaft angle falls is determined by quadrant detector. On the basis of the peak amplitude levels and quadrant information, the synchro shaft angle is computed. This method provides shaft position and speed in digital form. The reuse of quadrant detector in the evaluation of shaft speed shows the effectiveness of the proposed scheme.
Do Arab public opinion support policies of regional powers in MENA? View from Tunisia
ABSTRACT The Arab Uprisings and subsequent events continue to transform policies of regional and major powers toward the Middle East and North Africa. These powers have shown different approaches toward the Uprisings, ranging from support for the status quo to endorsing regime changes. Their policies have also exerted a significant impact on the course of events. Despite this growing importance and implications of policies of regional powers on the Uprisings and the Syrian conflict, we still do not know much about how the public assesses these policies and to what extent domestic cleavages shape these assessments. Using a nationally representative original survey conducted in 2014 in Tunisia, this study examines the perceptions of the policies of France, Turkey, and Saudi Arabia towards the Uprisings and the Syrian conflict. It finds that French and Turkish policies about the Uprisings have garnered substantial support among citizens, whereas most citizens negatively assess the Saudi policies. On the other hand, the majority of Tunisians negatively assess all these countries’ policies toward the Syrian conflict. Another major finding suggests that political identity reflecting secular/religious cleavages shapes how citizens view the policies of these three countries toward both issues, but its effect is higher in assessing the Uprisings.