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Components of LT switch gear: Switch Fuse Unit (SFU), MCB, ELCB, MCCB.

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Switchgear: The apparatus used for switching, controlling and protecting the electrical circuits and equipment is known as switchgear. Classification of Switchgear: Switchgear can be classified on the basis of voltage level into the following:  1. Low voltage (LV) Switchgear: up to 1 KV   2. Medium voltage (MV) Switchgear:  3 KV to 33 KV   3. High voltage (HV) Switchgear: Above 33 KV . Components of LT Switchgear: The term LT Switchgear includes low voltage Circuit Breakers, Switches, off load electrical isolators, HRC fuses, Earth Leakage Circuit Breaker, Miniature Circuit Breakers (MCB) and Molded Case Circuit Breakers (MCCB) etc i.e. all the accessories required to protect the LV system. The most common use of LV switchgear is in LV distribution board. FUSE: Fuse is the simplest and cheapest device used for interrupting an electrical circuit under short circuit, or excessive overload, current magnitudes. The action of a fuse is based upon the heating...
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Three Phase Induction Motor: Generation of Rotating Magnetic Fields, Construction and Working of a 3-ph Induction Motor, Squirrel cage IM, Slip-ring IM

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  Rotating Magnetic Field Rotating magnetic field is magnetic field which rotates in space about some point or axis. The North and South poles continuously rotates with a specific speed, called  synchronous speed . To understand the generation of the magnetic field  we will first imagine one stator of an electric motor where three-phase winding is physically distributed in the stator core in such a manner that winding of each phase is separated from other by 120 o in space. Although the vector sum of three currents in a balanced three-phase system is zero at any instant, but the resultant of the magnetic fields produced by the currents is not zero rather it will have a constant non-zero value rotating in space in respect to time. The magnetic flux produced by the current in each phase can be represented by the equations given below. This is a similar representation of current is a three-phase system as the flux is cophasial with the current . Where, φ R , φ Y and ...
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DC Circuits

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Ohm’s Law   Ohm's law state that the current through any two points of the conductor is directly proportional to the potential difference applied across the conductor, provided physical conditions i.e. temperature, etc. do not change. It is measured in (Ω) ohm. Mathematically it is expressed as  This constant is also called the resistance (R) of the conductor (or circuit) R= 𝑉 𝐼 In a circuit, when current flows through a resistor, the potential difference across the resistor is known as voltage drops across it, i.e., V = IR. Limitations of Ohm’s Law  Ohm's law is not applicable in unilateral networks. Unilateral networks allow the current to flow in one direction. Such types of network consist of elements like a diode, transistor, etc.  It is not applicable for the non-linear network (network containing non-linear elements such as electric arc etc). In the nonlinear network, the parameter of the network is varied with the voltage and current. Their parameters like ...
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