Utilisation - Elecrical engineering - Assignment Example

In this type of lamp, there is glass tube which is filled with a mixture of mercury vapour at low pressure and argon. The inner side of the tube has a phosphorous coating which is used to illuminate the light. As current flows through the electrodes in the tube, it goes through the gas which is contained between. Consequently, there is emission of ultraviolet light from the mercury arc which is converted to visible light by the fluorescent coating found on the inside of the tube. To facilitate proper lighting in this scenario, a high mercury pressure lamp is necessary to facilitate this lighting system.

This is due to the fact that this type of lamp produces less heat and uses less energy and thus it conserves energy while at the same time producing enough lighting. In the design of this type of lamp, an outer glass envelop is filled with nitrogen gas which acts as a coolant that keeps the arc tube at correct temperatures. This type of lamp contains a quartz discharge tube which is filled with argon gas and small amount of mercury which is in liquid form. Two electrodes are located at the ends of the tube which begins the discharge.

A 10 – 30 Ω resistor is connected in series with the secondary electrode. On switching on the light, at first there is no current flow. Then the power supply voltage appears across the main electrode and between one of the mains electrodes and the secondary electrode through the series resistor (B & B training Associates Limited). Consequently, there is production of an arc between the secondary and the main electrode resulting in occurrence of ionisation. The pressure and the heat build-up resulting in the formation of more high pressure and vaporised and high pressure arc between the electrodes.

It is made of a sintered aluminium oxide tube that is being supported by two rods. The inside of the glass is coated with white material that facilitates spreading of the light. There is a combination of sodium and