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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 ...
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.
In electromagnetism, a toroidal moment is an independent term in the multipole expansion of the electromagnetic field which is distinct from magnetic and electric multipoles. In the electrostatic multipole expansion, all charge and current distributions can be expanded into a complete set of electric and magnetic multipole coefficients.
A change in winding position, degradation in the insulation, etc. will result in change in capacitance or inductance thereby affecting the measured curves. [ 2 ] Tests are carried out periodically or during major external events like short circuits and results compared against the initial signature to test for any problems.
Fig. 1 L P σ and L S σ are primary and secondary leakage inductances expressed in terms of inductive coupling coefficient under open-circuited conditions.. The magnetic circuit's flux that does not interlink both windings is the leakage flux corresponding to primary leakage inductance L P σ and secondary leakage inductance L S σ.
Certain types of variable-speed drives recover slip-frequency power from the rotor circuit and feed it back to the supply, allowing wide speed range with high energy efficiency. Doubly-fed electric machines use the slip rings to supply external power to the rotor circuit, allowing wide-range speed control.
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 .