The amount of flux produced by the magnet indicates the strength of the magnet. The more the magnetizing force (MMF), the more is the flux produced. The more the opposition to the flux path (i.e., reluctance or magnetic resistance) less is the flux produced. This relationship is expressed as Flux = MMF/ Reluctance Reluctance is the opposition offered by the material in the flux path to the establishment of the flux. The reluctance in a magnetic circuit is similar to the resistance in an electric circuit. Reluctance is the inverse of permeance. MMF = Flux/Permeance
A DC motor can be operated from a single-phase AC supply. The direction of the torque produced by a DC machine is determined by the direction of current flow in the armature conductors and by the polarity of the field. Torque is developed in a DC machine because the commutator arrangement permits the field and armature currents to remain in phase, thus producing torque in a constant direction. A similar result can be obtained by using an AC supply, and by connecting the armature and field windings in series.
While estimating the overhead lines, the first and last pole is always earth connected and after every 3rd electrical pole, the fourth pole is earthed. Therefore, the approximate number of required ground set = 4
⇒ The electric potential at a point is defined as the work done in bringing the unit positive charge ( +1C) from infinity to that point. The work done is independent of the path taken. Its unit is Volt (V). ⇒ Potential Difference (pd or V) is a measure of the difference in charge between two points in a conductor. Its unit is Volt (V). ⇒ The difference in charge produced by the battery is stored in the battery as electrical potential energy and is called electromotive force (shortened to emf). Electromotive force is also measured in volts. Its unit is Volt (V). ⇒ Electric flux is a measure of how much the electric field vectors penetrate through a given surface. The SI unit of electric flux is N.m2/C. Electrical potential, Potential difference, Electromotive force has the same SI unit i.e Volt (V). Hence Electric flux is alike from others.
EXAMIANS