Saturday, 11 December 2010

Electrical materials Gap

Sealing material used to separate the parts of the voltage. For that use insulation materials should consider the nature kelistrikanya. In addition, also need to consider the thermal properties, mechanical properties, and chemical properties.
Electrical properties including resistivity, permittivity and dielectric loss. Require sealing material having a large resistivity for currents that leak as small as possible (negligible). Noteworthy here is that the hygroscopic insulation materials should consider its use in damp places because resistivitasnya will go down. Resistivity also will go down if the applied voltage rises.

The amount of capacitance insulating material that serves as a dielectric is determined by permitivitasnya, in addition to distance and surface area. The amount of air permittivity is 1.00059, while the for solid and liquid is always greater than that. If the insulation material given alternating voltage, there will be energy that is absorbed by the material. The amount of energy absorbed losses of insulating material is directly proportional to voltage, frequency, capacitance, and dielectric loss angle. The angle is located between the capacitive currents and total current (Ic Ir).

Temperature also affects the mechanical strength, hardness, viscosity, resistance to chemicals and so forth. Insulating materials can be damaged due to the heat at a certain time. This time is called aging heat insulation materials. While the ability to withstand a certain temperature materials without heat damage occurs is called resistance. According to the IEC (International Electrotechnical Commission) is based on the working temperature limit of materials, insulation materials used at temperatures below zero (eg, on airplanes, mountains) should also be taken into account because at temperatures below zero insulation material will become hard and Regas. In electrical machinery, Conductor temperature rise is influenced by the resistance heat insulation materials. The insulation material should be able to continue the heat didesipasikan by Conductor or magnetic circuit in the air around him.

The ability of soluble insulating material, chemical resistance, hygroscopic, vapor permeability, the influence of tropical, and radioactive resistance need to be considered on specific use. The ability of soluble material is required in determining the kind of solvent for a material and in testing the ability of insulation material toward a particular fluid during impregnated or in usage. The ability of soluble solid material can be calculated based on the number of surface material that can dissolve every unit of time if given solvent.Generally the ability of soluble material increases if the temperature is raised.

The resistance to corrosion due to gas, water, acids, alkalis, and salt also nervariasi insulation materials between one insulating material usage in active chemical concentration areas, installation of high voltage, and temperature above normal. Moisture can reduce the power insulation material. Because insulating materials also have hygroscopic properties during storage or usage then endeavored to prevent moisture absorption by the insulating material, to provide moisture absorbent material, the compound P2O5 or CaC12. Materials molecules containing hydroxyl group (OH) higrokopisitasnya relatively large compared to paraffin and polietilin material that can not absorb moisture. Insulation material should also have a vapor permeability (ability to pass steam) are great, especially for materials used for cable insulation and home capacitors. In the wet tropics made possible the growth of fungi and insects. The high temperature accompanied by humidity for a prolonged period can cause a decline in the ability of insulation.Therefore, insulating materials should dipisi anti-fungal materials (paranitro phenol, and pentha Chloro phenol).

The use of insulating materials are often influenced by a variety of radiation energy that can affect and change the properties of insulation materials. Solar radiation affects the aging of materials, particularly if contact with oxygen. UV rays can damage some organic material. T is the mechanical strength of elasticity. X-ray beams from nuclear reactors, isotope radio particles also affects the ability of insulating materials. Mechanical properties of materials including tensile strength, modulus of elasticity, hardness and degree of insulation materials is also a consideration in choosing a type of insulating material.

Class Materials Distribution Gap

Electrical insulation materials can be divided into several classes based on the maximum working temperature, which is as follows:

1. Class Y, the maximum working temperature of 90 ° C
Included in this class is an organic fibrous material (such as cotton, natural silk, synthetic wool, rayon polyamide fibers, paper, prespan, wood, polyacrylic, polyethylene, polyvinyl, rubber, etc.) that are not dipped in varnish materials or other dyes . Included also thermoplastic materials that can be soft at low temperatures.

2. Class A, the maximum working temperature of 150 ° C
Namely fibrous material from class Y that has been dipped in asphalt or varnish compounds, transformer oils, the email is mixed with varnish and poliamil or submerged in liquid dielektrikum (like insulation fiber immersed in transformer oil). These materials are cotton, silk, and paper that has been dyed, including wire email (enamel) that coated-oleo-resin and resin-polyamide.

3. Class E, the maximum working temperature of 120 ° C
Namely enamel wire insulation material using a binder polyvinylformal, polyurethene and epoxy resins and other binders similar to cellulosic material, pertinaks and tekstolit, triacetate film, polyethylene terephthalate film and fiber.

4. Class B, the maximum working temperature of 130 ° C
Namely that is non-organic materials (such as mica, glass, fiber, asbestos) are dyed or bonded into one with a varnish or compound, and usually heat resistant (with oil-based dryer, bitumin sirlak, bakelite, etc.).

5. Class F, maximum working temperature of 155 ° C
Organic materials are not dyed or glued together with epoxy, polyurethane, or high heat-resistant varnish.

6. Class H, the maximum working temperature of 180 ° C
All the material composition of base material with mica, asbestos and glass fiber is dipped in silicone without any mixture of fibrous materials (paper, cotton, etc.). In this class, including silicone rubber and pure polyamide wire email.

7. Class C, the working temperature above 180 ° C
Inorganic material that is not dyed and not bound by organic substance, such as mica, heat resistant mikanit (using inorganic binder), mikaleks, glass, and ceramic materials. Only one organic material that belongs to the class C is politetra fluoroetilen (Teflon).

Various kinds of insulation materials
• Materials for solid insulation, electrical materials can be grouped into several types, such as: minerals, fibrous materials, glass, ceramics, plastics, rubber, ebonite and bakelite, and other materials are compacted.
• Material sealing liquid form, this type of insulation that is widely used in electrical engineering is water, transformer oils and cable oils.
• Material sealing gas form, which is often used for electrical engineering including: air, nitrogen, hydrogen, and carbon dioxide.


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Electrical materials Gap
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