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Looking out from the axis, sometimes the winding is on the inside of the core and sometimes on the outside of the core. It is not axially symmetric in the near region. However, at points a distance of several times the winding spacing, the toroid does look symmetric. [7] There is still the problem of the circumferential current.
With the toroidal core winding technology an electric coil or winding is created by winding an electrical conductor (e.g. copper wire) through the circular ring and evenly distributing it over the circumference (Toroidal inductors and transformers, toroidal chokes). Before the winding starts, the Toroidal / Magnetic core is mounted into a ...
Field-reversed configurations and spheromaks are together known as compact toroids. Spheromaks and FRC differ in that a spheromak has an extra toroidal field. This toroidal field can run along the same or opposite direction as the spinning plasma. [22] In the spheromak the strength of the toroidal magnetic field is similar to that of the ...
A Rogowski coil is a toroid of wire used to measure an alternating current I(t) through a cable encircled by the toroid. The picture shows a Rogowski coil encircling a current-carrying cable.
Worst-case inrush happens when the primary winding is connected at an instant around the zero crossing of the primary voltage (which for a pure inductance would be the current maximum in the AC cycle) and if the polarity of the voltage half-cycle has the same polarity as the remanence in the iron core has (the magnetic remanence was left high ...
As the excitation winding is rotated through 180 degrees, the voltage induced in the series winding changes from adding to the supply voltage to opposing it. By selection of the ratios of the number of turns on the excitation and series windings, the range of voltage can be adjusted, say, plus or minus 20% of the supply voltage, for example.
As a simple example from the physics of magnetically confined plasmas, consider an axisymmetric system with circular, concentric magnetic flux surfaces of radius (a crude approximation to the magnetic field geometry in an early tokamak but topologically equivalent to any toroidal magnetic confinement system with nested flux surfaces) and denote the toroidal angle by and the poloidal angle by .
Accurate measurement of low currents (a few milliamperes) with a current transformer clamp is more difficult. The range of any given meter can be extended by passing the conductor through the jaw multiple times. For example a 0–200 A meter can be turned into a 0–20 A meter by winding the conductor 10 times around the jaw's core.