Electric Potential Boundary
 | 151 - Insulation Evaluation Analysis of a Power Transformer
| Module:EL | 2012-07-31 | A transformer is an electrical device that uses electromagnetic induction to convert the voltage level of alternating current power. Among transformers, power transformers that are used in power conversion have extremely high electric fields applied to their coils, so insulation technology like the winding structure, insulating materials, and insulation structure are vital in attaining miniaturization and higher capacity. In addition to normal power conversion, a transformer's insulation structure has to be designed to be able to withstand lightning strikes and excess voltage during short circuits.
A transformer's dielectric strength is dependent on the electric field intensity applied to the insulating material, so the electric field intensity needs to be examined before the safety factor for the insulation breakdown can be estimated.
This Application Note shows how to obtain the electric field intensity distribution when a lightning strike or short circuit occurs and the assumed maximum voltage is applied to the winding.
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  | 131 - Stray Capacitance Analysis of a Motor
| Module:EL | 2013-01-28 | AC motors that drive PWM inverters are widely used in household appliances.
Motors used for PWM inverter power supplies are known to produce shaft voltage which reduces the reliability and life span of the motors.
It is advantageous to investigate the stray capacitance using an analysis in advance because the shaft voltage is produced by the stray capacitance of the motor.
This example presents the use of an electric field analysis to obtain the stray capacitance between the IPM motor's coil and stator core, rotor core and stator core, and inner and outer rings of the bearing.
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 | 73 - Analysis of Capacitance of a Parallel Plate Capacitor
| Module:EL | 2013-01-28 | Capacitors are widely used as basic passive components in a variety of electric circuits. Parallel plate capacitors are taken up as the subject matter for how to obtain capacitance, a basic electric property, because they follow simple phenomena. Two electrode plates are placed in the air to face each other. When a constant electric potential difference is applied to them, they store an electric charge. The capacity of the charge stored in the electrode plates changes depending on the permittivity of the dielectric material between them.
This Application Note explains how to use JMAG to calculate the capacitance when the dielectric material is air and when it is a high permittivity material, while obtaining the amount of charge in each.
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