Chokes

Core induction chokes and coreless inductors are a large group of TRAFECO products. We design and supply chokes and coils that work in many industries. We can make an inductive component designed to work in almost any industrial application. Numerous applications in different operating conditions and applications mean that chokes have diversified in terms of performance and design. Chokes are components that operate under extremely different conditions and forcing depending on the application. Power electronics brings a number of applications for smoothing and energy storage chokes where they are subjected to high frequency components of the current. This meant that the choke and core design had to be changed to limit the additional losses from high frequency currents. For technically challenging applications, we have developed the modern low-loss CoreECOTM bonded multi-slit core technology. CoreECOTM’s low-loss, multi-slot core makes it possible to reduce losses occurring in the core — near the gaps and in the choke winding and structure.

Drive system chokes installed at the input and output of inverters operate in the presence of higher voltage and current harmonics. The action of harmonic frequency currents on the choke core and winding causes the occurrence of additional eddy current and hysteresis losses. Furthermore, in chokes, especially at high power and higher frequencies, the phenomena causing additional losses — skin effect and proximity effect — become more pronounced. . The design of the choke windings and the core shall as far as possible take account of these interactions. The windings of the chokes have a special design to reduce losses and mitigate the mentioned impacts. The CoreECOTM multi-slot core is excellent at reducing losses from harmonic currents.

Similar effects occur in chokes used in power generation and reactive power compensation or filtration. Inductive components operating in harmonic filters are required to have their inductance characteristics as a function of current as linear as possible. Chokes with cores of magnetic materials are subject to the natural ability to saturate the magnetic circuit. Under such conditions, maintaining a linear inductance path is very difficult and requires special technological procedures to hinder local saturation of the core. Designing core chokes with extended linearity of inductance characteristics requires lowering the operating induction in the core which leads to increased mass and size of the component. If there is an absolute need to maintain the linearity of the magnetic characteristics, the best solution is to use coreless coils. AirECOTM type coreless coils have linear inductance characteristics over the full load current range. Air coils find numerous applications in filtration and circuits with significant overloads. The coils are designed in two varieties – natural air cooling and forced air cooling. Due to the lack of a flux focusing core, the coils interact strongly with ferromagnetic structures in the vicinity. A ferromagnetic coil housing or a massive structure in the immediate vicinity can affect the inductance value and the coil’s own losses. All inductive components can be supplied in enclosures with the required degree of protection. Factory mounted chokes and coils are designed to operate in a limited cooling space and the housing material takes inductive influences into account.

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