Determine transformer full load amps from nameplate or formulas. Find transformer multiplier based on impedance tolerance. Calculate transformer let-through short-circuit current using multiplier. Apply "f" factor for fault type and conductor length. Calculate symmetrical RMS current using "M" multiplier
Inrush current is the maximum instantaneous input current when a device is turned on. AC motors and transformers can draw several times their normal current during startup. Power converters have higher inrush currents due to capacitor charging
Electromagnetic coil is a wire in spiral or helix shape. Current through wire creates magnetic field, coils increase field strength. Magnetic field direction determined by right hand grip rule. Core area is hole in center, windings are wire loops
Toroidal components use circular magnetic cores with wire wound around them. Toroidal shape provides superior electrical performance compared to rectangular cores. Symmetry reduces leakage flux and electromagnetic interference. Toroidal windings are up to 50% lighter than other core designs
Alternating current (AC) reverses direction and changes magnitude continuously. AC is used for power distribution and consumer appliances. Most power circuits use sine waveform with positive half-period corresponding to current direction
Magnetic cores confine magnetic fields in electrical and electromechanical devices. Core materials include ferromagnetic metals like iron and ferrimagnetic compounds. Magnetic field lines concentrate in core material due to high permeability