What is the capacitor?

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 The Capacitor.         A capacitor is formed when two conductors, usually of aluminium, are separated by an insulator sus as paper ect. For use in motors the strips are rolled together into a compact unit and placed into a sealed metal or plastic container. This may be either cylinderical or rectangular in shape and may be mounted on, in, or away from the motor. Two terminals or leads are provied for connection. The name capacitor is descriptive of the operation of the device. The capacitor acts essentially as a storage units that is,has capacity to store electricity and provides a leading current to the auxiliary or starting winding. All capacitors have this quality and all are electrically the same;they differ only in mechanical construction.     THE OIL-FILLED CAPACITOR                 This capacitor is used mainly in the permanent-split capacitor motor and for the two-value capacitor motor. The capacitor use an oil-impregnated paper as the dielectric and are permanently conne
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Induction Motor

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This motor is quite different from a D.C. motor because supply is not given to its rotor (armature) but the e.m.f. is induced in the rotor  when stator is supplied which produces current in the rotor and the motor runs. Thus this motor is called induction motor. Nowadays for each work at each place A.C. single phase or 3phase motor is used.
The parts of this motor are as follows:-
1.Stator.
2.Rotor.
3.End cover.
4.Bearing.
5.Fan.

1.Stator: This is made of high silicon steel strips 0.3 to 1.35mm thick combining together which are called laminated strips and combination is called laminated core. The core has open or semi closed slots. In these slots winding is done. This core is fitted in a frame so that any external mechanical injury may not take place and rotor may rotet easily.
2.Rotor: It is also made of high Silicon steel strips 0.3 to 1.35 mm thick combining together. It has closed type slots in which winding is done. The winding is done with thick strips or rods. Nowadays melted aluminum is filled in these slots which work as winding. In big motor thick copper rods are inserted in the slots and end rings are connected (shorted) at the end of the rods by gas welding. This winding is called squirrel cage winding.
3.End cover: These are made of cast iron and keep the rotor exact in the centre of this stator so  that the rotor may move easily. These are fitted with blots with the stator frame. The frame also is made of cast iron.
4.Bearing: Mostly in 3 phase motors ball bearings are used and small single phase motor bush bearings are used. Their working is to give the rotor free rotation in the stator.
5.Fan: In motor, its working is to cool the motor. Mostly these are made of cast iron and fitted on the rotor shaft. When the motor runs on load, the heat is produced in the motor due to losses. If this heat is not transferred out, the winding will be brunt. The fan serves the purpose of transferring heat from inside to outside of the motor. It sucks the cold air from the atmosphere. This air comes inside the motor through holes and goes out after cooling the winding of the motor. In many motors this fan is fitted on the rotor near to the winding and in many motors it is fitted outside the cover I.e. after fitting the cover and then a M.S.sheet or cast iron. Fan,cover is fitted which cover this fan.



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