Hong-Soon Chang

Analysis on the magnetic properties of an isolated phase bus system

The isolated phase bus in power plants is used to carry large current from a generator to a power transformer. The magnetic field distribution and eddy current characteristics of a three-phase isolated phase bus have been investigated using the finite element method. This paper also describes the effects of material, thickness and radius of enclosure on the eddy current distribution.

Finite element analysis of an anisotropic ferrite bonded magnet for BLDC motor design

In many cases, ferrite bonded magnets used in inner-rotor type small brushless DC (BLDC) motors do not have rotor core, and the magnetization directions of permanent magnets do not have only parallel or radial direction. In this paper, the magnetization directions of a ferrite bonded magnet are analyzed by finite element analysis for magnetization procedure. The characteristics of an inner-rotor type BLDC motor are analyzed by using the analyzed magnetization model. In the analysis, the overhang effect of the magnet is calculated by using 3-D FEM. The validity of the analysis method is verified by comparing the analyzed results with measured ones.

Performance Analysis of an ORC System for Two Different Working Fluids

The organic Rankine Cycle (ORC) uses a kind of refrigerant as a working fluid that evaporates at relatively low temperature, as the Rankine Cycle uses superheated steam as the working fluid. A small scale ORC test bench was installed, and two different working fluids (R245fa and R134a) were injected into the test bench. The test bench was in operation with the two different working fluids under the same conditions. The effects against the system performance from the different working fluids were analysed, and root causes were identified. Other factors reflecting the power generation efficiency were also found. A conclusion was drawn, that R245fa makes the system perform better, than R134a.

Micro Pattern Control of Metal Printing by Piezoelectric Print-head

We were analyzed the piezoelectric characteristic for electronics printing to inkjet printing system. These applications were possible use to Actuator, MEMS, FPCB, RFID, Solar cell and LCD color filter etc. Piezoelectric print head is firing from ink droplet control consideration ink viscosity properties. At this time, micro pattern for PCB metal printing was possible by droplet control of piezoelectric driving. These driving characteristics are variable voltage pulse waveform. We are used the piezoelectric analysis software of Finite Element Method (FEM), Piezoelectric design parameters are acquired from piezoelectric analysis, and measurement of piezoelectric. It designed for piezoelectric head to possible electric print pattern of inkjet printing system. For this validity we were established through in comparison with simulation and measurement. Designed piezoelectric specification obtained voltage 98V, firing frequency 10 kHz, resolution 360dpi, drop volume 20pl, nozzle number 256, and nozzle pitch 0.33 mm.