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  Selecting cable The following are some points you should consider when selecting cable for a particular application: 1. Current carrying capacity Each component or appliance connected to a circuit will have a current draw associated with its operation and it is important that the cable supplying power to these is capable of carrying the normally expected current, plus a margin of safety. If it is not capable then it is likely to result in the cable becoming hot and potentially catching fire. Although fuses are used in the circuit to protect the cable, the cable itself should be of an adequate rating to prevent this over-heating occurring under normal circumstances. You might find it useful to read our Electrical Circuit Basics article for using the equation I = P/V where the following example is given: If we wanted to wire up a light that we know has a power rating of 50W, then using I = P/V the current draw would be 50W/12V = 4.17A.   This tells you that you could use a cable with a

  Vacuum Circuit Breaker A breaker which used vacuum as an arc extinction medium is called a vacuum circuit breaker . In this circuit breaker, the fixed and moving contact is enclosed in a permanently sealed vacuum interrupter. The arc is extinct as the contacts are separated in high vacuum. It is mainly used for medium voltage ranging from 11 KV to 33 KV. Vacuum circuit  breaker  has a high insulating medium for arc extinction as compared to the other circuit breaker  .  The pressure inside the vacuum interrupter is approximately 10 -4   torrent and at this pressure, very few molecules are present in the interrupter. The vacuum circuit breaker has mainly two phenomenal properties. High insulating strength: In comparison to various other insulating media used in circuit breaker vacuum is a superior dielectric medium. It is better than all other media except air and SF 6 , which are employed at high pressure. When an arc is opened by moving apart the contacts in a vacuum, an interruptio

  Introduction of electrical generator An electric generator is a device which is used to produce electric energy, which can be stored in batteries or can be directly supplied to the homes, shops, offices, etc.  Electric generators work on the principle of electro magnetic induction  .  A conductor coil (a copper coil tightly wound onto a metal core) is rotated rapidly between the poles of a horseshoe type magnet . The conductor coil along with its core is known as an armature. The armature is connected to a shaft of a mechanical energy source such as a motor and rotated. The mechanical energy required can be provided by engines operating on fuels such as diesel, petrol, natural gas, etc. or via renewable energy sources such as a wind turbine, water turbine, solar-powered turbine, etc. When the coil rotates, it cuts the magnetic field which lies between the two poles of the magnet.  The magnetic field will interfere with the electrons in the conductor to induce a flow of electric curre

  What is the Purpose of a Transfer Switch ?  A automatic transfer switch (ATS) is a gadget that transfer a force supply from its essential source consequently to a reinforcement generator when it detects a disappointment or blackout happening in the essential source until utility force is reestablished.  The ATS is associated with both essential and reinforcement power sources, and fills in as a delegate between the force sources and your structure or hardware, going about as an electrical transfer. An ATS can likewise go about as a repetitive, rack-mounted force supply for hardware that is associated with a force source with just one line.  How does an transfer switch work?  The main breaker in the transfer switch switches the force source from your utility capacity to a backup generator. The structure can't be associated with both the generator and utility force simultaneously. The main breaker moves power from one source to the next. This forestalls the generator power from bac

DIRECT ON-LINE (DOL) starter: Direct On-Line is the simplest and cheapest method used for starting three-phase motor. Dol is used for up to 5 HP motor. dol starter is more popular due to the low price.  It connects the motor directly to supply without a reduction in supply voltage and apply full line voltage to 3 phase motor.this is the main disadvantage of dol starter.HP motor required special unit called a motor starter.  Three phase induction motors control and power circuit consist MCB or fuse unit which connected in series with the supply. Power contactor, thermal Overload relay for protection and stop and start push button. Working Principle of Direct online starter (DOL Starter ) : 1) To start the motor, start push button is pressed. After that, the main power contactor coil energized due to electromechanical action and this latch contactor pole.it applies full line voltage to the motor terminals. and the motor starts running. The motor will draw a very high inrush current for a

  Star delta starter working principle theory There are many different starting methods are used to start a three-phase induction motor like Star delta starter. One of them, popular and cheapest is a Direct online starter. But its use limited for smaller HP motor, to start higher rating 3 phase motors star-delta starter is used. Star-delta starter is useful where all six terminals of the motor are accessible.  we will discuss star delta starter working principle with help of power and control diagram, Theory, connection wiring diagram, parts like contactor, mcb, fuses, a timer circuit, overload relay. Star-Delta starter is the simplest starting method for reducing the inrush starting current of Induction motor. The starter can be used with all squirrel-cage induction motors that are delta-connected for normal operation.  The reduction of the high motor current causes a reduction of the starting torque of the motor. Star-delta starting is therefore especially suitable for drives that a