State applications of : (i) PVC paper (ii) Porcelain with type of class based on withstand temperature is insulating material.
1 Answer
(i) Applications of PVC Paper
"PVC paper" typically refers to synthetic paper made from Polyvinyl Chloride resin or paper that is heavily coated with PVC. It is not traditional paper but a plastic sheet that mimics the properties of paper (like printability) while offering superior durability.
Key Properties: Waterproof, tear-resistant, chemical-resistant, durable, and excellent printability.
Applications:
- Identification Cards: Used for ID cards, driver's licenses, membership cards, and access control cards because they are rigid, durable, and can securely hold printed information and embedded chips.
- Menus and Signage: Restaurant menus, safety signs, and outdoor banners are often made from PVC paper because they can be easily wiped clean, resist spills and grease, and withstand weather conditions.
- Maps and Charts: Hiking maps, nautical charts, and construction blueprints benefit from being waterproof and tear-resistant, making them usable in harsh field conditions.
- Labels and Tags: Industrial labels for chemical drums, plant tags for nurseries, and luggage tags are made from PVC for their resistance to moisture, chemicals, and abrasion.
- Playing Cards and Games: High-quality, professional playing cards are often made of 100% PVC because they are durable, flexible, and can be cleaned, lasting much longer than paper-based cards.
- Manuals and Documentation: For machinery or in cleanrooms, manuals printed on PVC paper can withstand grease, oil, and frequent handling without degrading.
- Wristbands: Event, hospital, and resort wristbands are made from soft PVC for its durability and water resistance.
(ii) Applications of Porcelain as an Insulating Material
Porcelain is a ceramic material with excellent dielectric strength (it does not conduct electricity) and high thermal resistance. It is hard, mechanically strong, and highly resistant to weathering and chemicals, making it one of the most widely used materials for electrical insulation, especially in outdoor and high-voltage applications.
Insulation Class based on Withstand Temperature
Based on NEMA (National Electrical Manufacturers Association) standards, insulating materials are classified by their maximum allowable operating temperature. Porcelain falls into the highest temperature class:
- Class: Class C
- Maximum Withstand Temperature: Above 180°C (up to 1000°C for some types)
- Definition: Class C consists entirely of inorganic materials like mica, glass, quartz, and porcelain. It is used where extremely high temperatures are expected.
Applications of Porcelain:
1. High-Voltage Applications:
- Pin Insulators: Mounted on the cross-arm of utility poles to support electrical conductors in power distribution lines (typically up to 33 kV).
- Suspension Insulators: Used in high-voltage transmission lines. They are connected in a string of discs to suspend the heavy power lines from the transmission tower, with the number of discs depending on the voltage level.
- Strain Insulators: Used where a transmission line ends, or at a sharp corner, to withstand the lateral (horizontal) tension of the wires.
- Post Insulators: Used in substations and switching yards to support busbars, switches, and other high-voltage equipment.
- Transformer Bushings: A porcelain insulator that allows a high-voltage conductor to pass safely through the grounded metal tank of a transformer or circuit breaker.
2. Low-Voltage and High-Temperature Applications:
- Fuse Holders and Cartridges: The body of many cartridge fuses and fuse holders is made of porcelain to insulate the live parts and safely contain the heat and arc generated when a fuse blows.
- Lamp Sockets: Sockets for high-intensity bulbs (like halogen or incandescent lamps) are often made of porcelain to withstand the high heat generated by the bulb.
- Heating Element Supports: In electric furnaces, kilns, and space heaters, the heating coils are wound around or supported by porcelain insulators because they can withstand extreme temperatures while remaining excellent electrical insulators.
- Standoff Insulators: Used inside electrical enclosures and switchgear to support and insulate current-carrying busbars from the metal frame.