Section 3
... A wye-delta transformer connection introduces a 30o phase shift in positive/negative sequence voltages and currents because of the relative shift between line-to-neutral and line-to-ground voltages. Transformers are labeled so that 1. High side positive sequence voltages and currents lead those on t ...
... A wye-delta transformer connection introduces a 30o phase shift in positive/negative sequence voltages and currents because of the relative shift between line-to-neutral and line-to-ground voltages. Transformers are labeled so that 1. High side positive sequence voltages and currents lead those on t ...
Power_Networks - University of British Columbia
... • In electrical insulation, subjected to repetitive fast-front transients, the initial measurable indication is Partial Discharges(PD) in the insulation, such as motors driven by pulse modulated power electronics. It is important to understand the precursor deterioration processes. For example, gen ...
... • In electrical insulation, subjected to repetitive fast-front transients, the initial measurable indication is Partial Discharges(PD) in the insulation, such as motors driven by pulse modulated power electronics. It is important to understand the precursor deterioration processes. For example, gen ...
Magnetism - South High School
... “Is it true that the Earth‘s magnetic field is about to flip? Like football teams at half time, geophysicists think that the Earth’s magnetic poles could soon switch ends with the magnetic north pole becoming south, and the magnetic south pole becoming north. Fortunately, when they say ‘soon’ geophy ...
... “Is it true that the Earth‘s magnetic field is about to flip? Like football teams at half time, geophysicists think that the Earth’s magnetic poles could soon switch ends with the magnetic north pole becoming south, and the magnetic south pole becoming north. Fortunately, when they say ‘soon’ geophy ...
ABB helps distribution transformers survive rapid voltage transients
... encountered during normal operating conditions. Furthermore, the complicated internal structures of electric apparatus can act as multiresonant circuits. High frequencies can therefore additionally cause local amplification. The resulting stresses on the insulation system can significantly compromise ...
... encountered during normal operating conditions. Furthermore, the complicated internal structures of electric apparatus can act as multiresonant circuits. High frequencies can therefore additionally cause local amplification. The resulting stresses on the insulation system can significantly compromise ...
Design Methodology of LLC Resonant Converters for Electric Vehicle Battery Chargers
... additional diode reverse recovery losses compared with the region below resonance [19]. The FHA is still valid but less accurate in the below-resonance region; therefore, it is useful for qualitative analysis but not for optimal design procedure. Optimal design methods are developed based on the ope ...
... additional diode reverse recovery losses compared with the region below resonance [19]. The FHA is still valid but less accurate in the below-resonance region; therefore, it is useful for qualitative analysis but not for optimal design procedure. Optimal design methods are developed based on the ope ...
Maintenance For controllers TD03309002E
... Soot, smoke, or stained areas (other than inside arc chutes), or other unusual deposits, should be investigated and the source determined before cleaning is undertaken. Vacuum or wipe clean all exposed surfaces of the control component and the inside of its enclosure. Equipment may be vacuumed or bl ...
... Soot, smoke, or stained areas (other than inside arc chutes), or other unusual deposits, should be investigated and the source determined before cleaning is undertaken. Vacuum or wipe clean all exposed surfaces of the control component and the inside of its enclosure. Equipment may be vacuumed or bl ...
Resonant inductive coupling
Resonant inductive coupling or electrodynamic induction is the near field wireless transmission of electrical energy between two magnetically coupled coils that are part of resonant circuits tuned to resonate at the same frequency. This process occurs in a resonant transformer, an electrical component which consists of two high Q coils wound on the same core with capacitors connected across the windings to make two coupled LC circuits. Resonant transformers are widely used in radio circuits as bandpass filters, and in switching power supplies. Resonant inductive coupling is also being used in wireless power systems. Here the two LC circuits are in different devices; a transmitter coil in one device transmits electric power across an intervening space to a resonant receiver coil in another device. This technology is being developed for powering and charging portable devices such as cellphones and tablet computers at a distance, without being tethered to an outlet.Resonant transfer works by making a coil ring with an oscillating current. This generates an oscillating magnetic field. Because the coil is highly resonant, any energy placed in the coil dies away relatively slowly over very many cycles; but if a second coil is brought near it, the coil can pick up most of the energy before it is lost, even if it is some distance away. The fields used are predominately non-radiative, near fields (sometimes called evanescent waves), as all hardware is kept well within the 1/4 wavelength distance they radiate little energy from the transmitter to infinity.One of the applications of the resonant transformer is for the CCFL inverter. Another application of the resonant transformer is to couple between stages of a superheterodyne receiver, where the selectivity of the receiver is provided by tuned transformers in the intermediate-frequency amplifiers. The Tesla coil is a resonant transformer circuit used to generate very high voltages, and is able to provide much higher current than high voltage electrostatic machines such as the Van de Graaff generator. Resonant energy transfer is the operating principle behind proposed short range (up to 2 metre) wireless electricity systems such as WiTricity or Rezence and systems that have already been deployed, such as Qi power transfer, passive RFID tags and contactless smart cards.