Insulator (electricity) facts for kids
An electrical insulator is a special material that stops electricity from flowing easily through it. Think of it like a shield for electric currents! Common materials used for insulation include rubber, plastic, and glass. In big electrical machines like transformers and electric motors, a special paint called varnish is often used. Some switches even use insulating gases, like sulfur hexafluoride.
Wires that carry electricity are usually covered with an insulator. This makes sure the electricity goes where it's supposed to and helps keep us safe.
The word "insulator" can also mean the objects made from these materials. These objects can be made from many things, such as glass, silicone, rubber, plastic, oil, wood, dry cotton, quartz, and ceramic.
The kind of insulator used depends on what it's needed for. Insulators are very good at resisting electricity and don't let much current pass through. They help prevent electricity from escaping and make sure it flows efficiently where it's needed.
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How Insulators Work
Insulators have tiny particles called electrons that are tightly held in place. This means electrons can't move freely to carry an electric current. Because electrons can't move easily, electricity can't flow through the material.
This is different from a conductor, which is a material that lets electricity flow easily. Metals like copper are good conductors because their electrons can move freely.
Types of Insulators
In electric power transmission, which is how electricity travels from power plants to your home, there are three main types of insulators used on overhead power lines. These are pin insulators, suspension insulators, and strain insulators.
Pin Insulators
The pin insulator was one of the first types of insulators ever developed. It looks a bit like a mushroom and is fixed onto a pin on the power pole. Depending on how much voltage (electrical pressure) the line carries, a pin insulator can have one, two, or even three parts stacked together. They are typically used for lower voltage lines.
Suspension Insulators
The suspension insulator is used for very high voltages, usually above 33,000 volts. These insulators are made of several individual insulator discs connected together in a chain. They hang down vertically from the power pole or tower, holding the power line below them. The more discs in the chain, the higher the voltage it can handle.
Strain Insulators
The strain insulator is very similar to a suspension insulator. However, instead of hanging vertically, it is used horizontally. Strain insulators are used in places where the power line needs to handle a lot of pulling force or tension. This often happens at the end of a power line, or where the line makes a sharp turn. They help to relieve the stress on the wires.
Images for kids
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Three-core copper wire power cable, each core with an individual colour-coded insulating sheath, all contained within an outer protective sheath
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PVC-sheathed mineral-insulated copper-clad cable with two conducting cores
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Power lines supported by ceramic pin-type insulators in California, USA
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10 kV ceramic insulator, showing sheds
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High voltage ceramic bushing during manufacture, before glazing (1977)
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A three-phase insulator used on distribution lines, typically 13.8 kV phase to phase. The lines are held in a diamond pattern, multiple insulators used between poles.
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Bottom-contact third rail in a sheath insulator
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Suspension insulator string (the vertical string of discs) on a 275 kV suspension pylon
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Suspended glass disc insulator unit used in suspension insulator strings for high voltage transmission lines
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Open-wire telegraph pole with porcelain insulators in Quidenham, Norfolk, United Kingdom
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Egg-shaped strain insulator
See also
In Spanish: Aislamiento eléctrico para niños
