Mitigation of am interference in digital transmission

The plain-old-telephone-system (POTS) is now increasingly used to carry high-speed data such as for Internet purpose. However, problem can occur if the telephone network is in close proximity to an AM radio transmitter, transmitting high power signal at a frequency which overlaps the bandwidth of the Internet transmission. The interfering electromagnetic field can induced enough current and voltage in the telephone network and causing significant data errors. This report presents a study on the effects of high-powered AM transmission at 576 kHz on a digital transmission system. A GTEM Cell was used to generate the 576kHz clectric field intensity varying from lV/m to 15 V/m with 80% amplitude modulation. The electric field is imposed on a section of the cable and the Bit Error Rate (BER) is noted using Data Tools 5000. Shielding technique was employed using four conducted materials (soft steel, hard steel, aluminum and copper) in order to test the attenuation of the electric field reaching the cable. Measured results showed that copper (a= 5.87 x 107 S/m, fr =1) can reduce up to 70% of the BER. The relationship between electric field E and BER for copper is expressed as BER = 2 x 10~5 e0-3"^' +2.48x10"^ indicating that the BER increases exponentially with the magnitude of the applied electric field. It is obvious from the work done in this project that any network situated near a high-powered electromagnetic field transmitter should employ a good shielded cabling system. It is recommended that further study need to be carried out to find ways of mitigating the effects of the interfering field such filtering and grounding

Improved design of three phase hybrid excitation flux switching motor (HEFSM) with segmental rotor

This paper presents the new design of Hybrid Excitation Flux Switching Motor (HEFSM) using segmental rotor structure. HEFSMs are those that consists all the excitation flux sources at their stator with robust rotor structure. The rotor is designed as segmental due to the reason that segmental rotor has ability to yield the magnetic path for conveying the field flux to nearby stator armature coil with respect to the rotation of the rotor. This design gives the clear advantage of shorter end winding compared to the toothed rotor as there is no overlap winding between field excitation coil (FEC) and armature coil. In this paper the initial design of HEFSM with segmental rotor has been improved by changing segment span, FEC slot area and armature slot area until maximum torque and power of 33.633 Nm and 8.17 KW respectively have been achieved. Moreover coil test analysis, induced voltage, cogging torque, magnetic flux characteristics, torque vs. field current density and torque vs. power speed characteristics are examined on the basis of 2-D finite element analysis (FEA

THE USE OF THE FLY SWATTER GAME TO TEACH VOCABULARY MASTERY TO THE SEVENTH-GRADE STUDENTS

Vocabulary is one of language elements that are needed in learning and communication. The aimed of the study was to find out whether teaching vocabulary mastery using fly swatter game in vocabulary mastery significant or not. The method used quasi experimental method. The population of this research was all the seventh grade’ students of SMP Negeri 6 Palembang with total was 372 students. The samples took out were 68 students from 372 students by using purposive sampling method. They divided into the experimental and control group. The data were collected by using written test, those were pretest and posttest. The result of the test was analyzed by independent sample t-test. The mean in posttest of experimental group was 72.71, it was higher than the mean posttest of the control group which was 58.65. The result of T-Test obtained significance (sig. 2 tailed) was 0.002, which less or lower than 0.05. Since the sig. 2 tailed was less than 0.05, so the null hypothesis Ho was rejected and the alternative hypothesis Ha was accepted. It means that there was significant difference on students’ vocabulary mastery taught using Fly Swatter game than those who are not.

Permanent magnet flux switching torque performance indicator

Flux switching machine (FSM) offer advantages such as rotor robustness and simple driving circuit compared to competing machine. This paper attempts to process the torque, volume and current information from 35 latest Permanent Magnet (PM) FSM publication into a standardized Torque Performance Indicator (TPI), which are torque density, torque constant, torque constant density and torque-magnet ratio. The distribution median shows that torque density, torque constant, torque constant density and torque-magnet ratio are 23.24kNm/m3, 0.43Nm/A, 0.616Nkm/Am3 and 30.79Nm/kg respectively. Among many design variation, outer rotor configuration produces good values as overall in the TPI. This information can be used to guide the machine designer to compare and compete based on the standardized TPI

Preliminary Magnetization Pattern Study On Magnetic Gear

In this paper, radial anisotropic, circumferential anisotropic, parallel circular direction (PCD) and parallel radial direction (PRD) magnetization pattern are introduced and explained. Then, these magnetization pattern are simulated using JMAG Designer 16.0 on the coaxial magnetic gear with 2.33 gear ratio. Torque and efficiency are calculated and compared. The result shows that the radial anisotropic produce the highest torque and register the best efficiency versus the latter.With this study, it is hope that the designer can have second option to choose other type of magnetization without sacrificing the performance. The option may become in handy when the RAP becomes more expensive or difficult to procur

Flux Modulated Rotating Pole Piece Magnetic Gear

In this paper, the CMG is re-condition so that the pole piece act as the outer rotor instead of surface mount PM. This magnetic coupling of the CMG is similar to the conventional CMG which uses harmonic to transfer the torque and speed from the inner rotor to the outer rotor. The working principle of the proposed CMG is derived analytically and simulated using finite element software. For this recondition, the PM at the outer section become stationary hence, retaining sleeve can be removing. The proposed MG produced 18% higher average torque than the conventional MG with drawback in torque ripple. The proposed CMG also produce higher gear ratio than the same pole pair of conventional CM

Preliminary Study On Yoke Sizing Of Concentric Magnetic Gear

In this paper, torque, torque density, efficiency and efficiency slope of concentric magnetic gear (CMG) at different yoke sizes are evaluated using 2D finite element. Transient analysis when eddy current loss included and excluded are simulated. Efficiency to speed o used in this study is similar to the original gear ratio, 5.5. The change in the yoke size also effect the torque density of the CMG. The finding showed that the change in size at the outer rotor yoke influence the torque and efficiency the most. The smallest outer rotor yoke yields higher torque density of 55% then the average value in this study and slower gear efficiency degradatio

A New Speed Multiplier Coaxial Magnetic Gear

Due to certain conditions, electrical motor (EM) that operates at high speed may lead to magnetic saturation, thermal issue, and stress to rotor structure. Magnetic gear (MG) designed for speed multiplier enables the prime mover from EM to operate at lower speed while the output gear multiplies the speed by its designated gear ratio at reduced torque. In this paper, a new coaxial magnetic gear is designed for speed multiplier. The role between inner yoke with PM and pole piece is switched. The inner part of magnetic gear is made to be stationary while the pole piece becomes inner rotor. The working principle is presented analytically based on flux modulation techniques for torque and speed transmission. Torque characteristic and gear efficiency are analysed using finite element and compared with existing speed multiplier magnetic gear with the same gear ratio of 7/3. Based on the simulation result, the proposed speed multiplier MG offers 16% better torque density and 12% higher gear efficiency at higher speed range. The structure of the inner rotor is also found to be more robust as only pole piece ring together with plastic holding frame is rotated instead of yoke with P

Preliminary analysis of eddy current and iron loss in magnetic gear in electric vehicle

The inclusion of a high energy density permanent magnet into magnetic gear improves the machine's torque density. However, it also contributes to eddy current loss, especially in a high-speed application such in electric vehicle. In this paper, the losses from eddy current and iron loss are investigated on concentric magnetic gear (CMG). Torque multiplier CMG is designed with 8/3 gear ratio for this study. Iron loss and eddy current loss are compared and discussed. Based on this study, eddy current loss contributes to almost 96% of the total loss. This finding is hoped to direct the researcher to focus more on reducing loss associated with eddy current loss