When flux enters into the air gap, it passes through the air gap in terms of parallel ﬂux lines. There exists a force of repulsion between the magnetic lines of force which are parallel and having the same direction. Due to this repulsive force, there is the tendency of the magnetic flux to (spread out) at the edge of the air gap. This tendency of ﬂux to spread out at the edges of the air gap is called magnetic fringing.
Magnetic fringing increases the effective cross-sectional area of the air gap reduces the flux density. So leakage, fringing, and reluctance should be as small as possible. This is possible by choosing a good magnetic material and making the air Magnetic fringing gap as narrow as possible.
In the PMMC type instrument, the deflection is directly proportional to the current flowing through the instrument, we get a uniform scale for the instrument. It gives a uniform scale of upto 270° or more.
Td ∝ I
A practical parallel resonance circuit is represented by an inductance and a resistance id one branch and a capacitance in other branches.
At resonance in a practical parallel resonance circuit, the impedance is maximum. Hence, it is called a rejector circuit, and it exhibits the property of voltage magnification.
Z = L/CR
Atoms or ions with unpaired electrons are attracted to a magnetic field; the more unpaired electrons, the greater is the attraction. Such substances are called paramagnetic. Molecular oxygen is a paramagnetic gas by virtue of its two unpaired electrons.
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
A phase sequence is an order or sequence in which the currents or voltages of different phases attain their maximum values. In a three-phase system, there are only two possible phase sequences: R-Y-B (positive Phase Sequence) and R-B-Y (Negative Phase Sequence).