Loopy What Is Electric Cable: Lessons From The professionals > 자유게시판

• 목록
• 답변
• 글쓰기
• 게시판 리스트 옵션
  • 수정
  • 삭제

In the electric wire, the light and active magnesium oxide produced by Meishen Technology mainly plays the role of scorch retarder, vulcanization accelerator, acid-acceptor, stuffing bulking agent, high temperature resistance, abrasion-resistance, anticorrosive etching reagent and so on. Their rated current depend on the load current of the equipment to be protected and the ambient operational temperature. In the United States and Canada, low-voltage fuses to 1 kV AC rating are made in accordance with Underwriters Laboratories standard UL 248 or the harmonized Canadian Standards Association standard C22.2 No. 248. This standard applies to fuses rated 1 kV or less, AC or DC, and with breaking capacity up to 200 kA. In both cases, higher rated carriers had wider pins, so a carrier couldn't be changed for a higher rated one without also changing the base. Over the years MCBs have been made for both styles of base. There are two styles of fuse base that can be screwed into these units: one designed for rewirable fusewire carriers and one designed for cartridge fuse carriers. Cartridge fuse carriers are also now available for DIN-rail enclosures. Renewable fuses (rewirable or cartridge) allow user replacement, but this can be hazardous as it is easy to put a higher-rated or double fuse element (link or wire) into the holder (overfusing), or simply fitting it with copper wire or even a totally different type of conducting object (coins, hairpins, paper clips, nails, etc.) to the existing carrier.

In the UK, older electrical consumer units (also called fuse boxes) are fitted either with semi-enclosed (rewirable) fuses (BS 3036) or cartridge fuses (BS 1361). (Fuse wire is commonly supplied to consumers as short lengths of 5 A-, 15 A- and 30 A-rated wire wound on a piece of cardboard.) Modern consumer units usually contain miniature circuit breakers (MCBs) instead of fuses, though cartridge fuses are sometimes still used, as in some applications MCBs are prone to nuisance tripping. Text telegraphy consisted of two or more geographically separated stations, called telegraph offices. If you can turn a bunch of cords into one single cord, you could right away have things inside of your residence look a little much more organized. Fuses only sense overcurrent, or to a degree, over-temperature, and cannot usually be used independently with protective relaying to provide more advanced protective functions, for example, ground fault detection. The standard is in four volumes, which describe general requirements, fuses for industrial and commercial applications, fuses for residential applications, and fuses to protect semiconductor devices. These cables help transmit signal and video applications, data networks, telephones, and security cameras. For domestic applications, Miniature circuit breakers (MCB) are widely used as an alternative to fuses.

These fuses open in less than one cycle of the AC power frequency; circuit breakers cannot match this speed. A fuse can clear a fault within a quarter cycle of the fault current, while a circuit breaker may take around half to one cycle to clear the fault. An average desktop computer consumes about 200 to 300 watts in use, while laptops and mini PCs are made to take 50 watts or less. UL 248-1 sets the general requirements for fuses, while the latter parts are dedicated to specific fuses sizes (ex: 248-8 for Class J, 248-10 for Class L), or for categories of fuses with unique properties (ex: 248-13 for semiconductor fuses, 248-19 for photovoltaic fuses). A circuit breaker at 115 kV may cost up to five times as much as a set of power fuses, so the resulting saving can be tens of thousands of dollars. This is not the case with fuses, which rely on melting processes where no mechanical operation is required for the fuse to operate under fault conditions. Some types of circuit breakers must be maintained on a regular basis to ensure their mechanical operation during an interruption.

Special current-limiting fuses are applied ahead of some molded-case breakers to protect the breakers in low-voltage power circuits with high short-circuit levels. The standard ampere ratings for fuses (and circuit breakers) in USA/Canada are considered 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600, 700, 800, 1000, 1200, 1600, 2000, 2500, 3000, 4000, 5000, and 6000 amperes. High-voltage fuses are used to protect instrument transformers used for electricity metering, what is electric cable or for small power transformers where the expense of a circuit breaker is not warranted. Pole-mounted distribution transformers are nearly always protected by a fusible cutout, which can have the fuse element replaced using live-line maintenance tools. Medium-voltage fuses are also used to protect motors, capacitor banks and transformers and may be mounted in metal enclosed switchgear, or (rarely in new designs) on open switchboards. On the other hand, replacing a fuse without isolating the circuit first (most building wiring designs do not provide individual isolation switches for each fuse) can be dangerous in itself, particularly if the fault is a short circuit. When you start shopping for a projection TV, your first major decision will be whether to buy a front-projection or rear-projection model.