Sodium Vapour Lamp Construction and Working

Sodium Vapour Lamp : Principle : “Electrons are emitted from cathode by subjecting the surface of the cathode to very high electric stress so that electrons are forcibly ejected from orbits of atom against nuclear centrifugal force”. Construction and Working : It consists of inner tube of U shape fitted with neon gas and globules of sodium. For … Read more

Mercury Vapour Lamp and Mercury lodide Lamps

Mercury Vapour Lamp : Q. Explain with neat sketch construction and working of high pressure mercury vapour lamp. Principle : “When mercury discharge under low pressure gives mainly ultraviolet radiations. If pressure is increased to one or two atmospheres, its proportion of radiations in visible spectrum is increased and we get light having bluish tinge”. Construction … Read more

Reasons of Fault Occurrence in Electrical Power System

Q. Explain the causes for faults. Q. State the causes of fault. Mostly the faults are caused by failure of insulation. The failure of insulation results in short circuits which are very harmful. Faults are also caused by breaking of conductors due to excessive heat or mechanical stresses. Most of the faults on Transmission lines … Read more

Functions of Protective Systems

State the functions of protective system. As mentioned above, protective system should operate automatically under abnormal condition within minimum time. Apart from this it should have following essential features : Quick operation : To minimize the damage to the faulty part, the switchgear must operate as quickly as possible after the occurrence of fault If … Read more