In: Electrical Engineering
1.Write down the properties and the types of insulating materials used in the construction of power and distribution transformers.
2. What are the different types of magnetic materials? Distinguish between hard and soft magnetic materials.
3.Explain Hall effect, hall coefficient and its value in different semiconductor
4.Explain with graphical representation the variation of mobility with temperature
5.Give the general electrical and magnetic characteristics of ferrites. List its applications
Question-1-(Solution)----> Properties and the types of insulating materials used in the construction of power and distribution transformers are listed below
(i) Wood-based laminates-- Such insulating laminates are used in areas that require higher mechanical and lower electric strength. They are used in making a variety of components like coil clamping rings, cores, yokes, and supports.
(ii) Pressboard-- Used in designing of transformers, Pressboard is made up of vegetable fibers that contain huge amounts of cellulose. These pressboards can be moulded into any shape to be used in transformers; the most commonly seen shapes being angle rings and caps.
(iii) Insulating oil-- Insulating oil is one of the most important components within a transformer that acts as both an electrical insulator and coolant to dissipate heat losses.Insulating oil is obtained by fractional distillation and subsequent treatment of crude petroleum.
(iv) Insulating paper-- Insulating paper is made up of vegetable fibers that are felted together to form a sheet.When this insulating paper is put into the insulating oil under vacuum, it attains extremely high electric strength.
(v) Insulating tape-- Insulating tape is used for various taping purposes. These are available in a variety of forms like cotton tapes, woven tapes, glass woven tapes, and phenol laminated paper base sheet. These tapes are used in areas where high strength is required. They are also used for banding of transformer cores.
Question-2-(Solution)---->
Question-3-(Solution)---->
Question-4-(Solution)----> Effect of Temperature on Mobility
Question-5-(Solution)---->