Identified with the Isolation symbol only, off load isolators are not rated to make or break loads. The table to the right lists a few examples of common electrical loads. The AC-21 Amp rating is applicable for resistive loads and the AC-23 kW rating for inductive motor loads. On Load Isolators are labelled with both an AC-21 Amp rating, and an AC-23 kW rating. It is logically a combination of the “Switch”, and the “Disconnector” (Isolation) symbols, explained to the right. On Load Isolators are easily identified by the above symbol on the switch label, which is compulsory. Identifying “On Load Isolators” by the product label In addition to the physical handle test, there are electrical threshold tests to ensure current will not jump the contact gap or track to earth under specified fault conditions. This communicates very effectively that isolation has not been achieved and that the circuit or equipment is not safe, and has not been isolated. Should there be one welded contact, the OFF position cannot be reached, and a padlock device cannot be fitted, even with three times the normal operating force being applied and when released the handle returns to ON. Example these switches cannot be turned to OFF (handle moved to the off position) unless all the main contacts have physically opened. They are electrically capable of making and breaking the load under normal conditions and specified overload conditions and also pass electrical and mechanical tests to comply as isolators. They are switch devices that cut off a circuit or equipment from a source of power and ensure that the electrical circuit or equipment is completely isolated in order to conduct maintenance, servicing, modification or repair.įor the above applications, a 1 pole isolator for single phase, or a 3 pole isolator for three phase are generally installed. Commonly referred to as Isolating switches, an “On Load Isolator” is the most common piece of equipment used to achieve isolation. The purpose of isolation is to provide protection against electrical hazards such as electric shock, burns and ballistics (the effects of arc flash), and the unintentional start-up of machinery. You can simply and quickly drop the ready-to-use objects from libraries into your document to create the electrical diagram.Isolators are relied on by electricians, maintenance personnel, plant operators and domestic property owners to isolate everything from a hot water cylinder or heat pump at home, to heavy industrial machinery in the workplace or farm. They are used for television broadcasting, cell phones, satellite communication including GPS, personal radio services including Wi-Fi and Bluetooth, walkie-talkies, cordless phones, and numerous other applications.Ģ6 libraries of the Electrical Engineering Solution of ConceptDraw PRO make your electrical diagramming simple, efficient, and effective. UHF radio waves propagate mainly by line of sight they are blocked by hills and large buildings although the transmission through building walls is strong enough for indoor reception. Lower frequency signals fall into the VHF (very high frequency) or lower bands. Radio waves with frequencies above the UHF band fall into the SHF (super-high frequency) or microwave frequency range. Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 MHz and 3 GHz, also known as the decimetre band as the wavelengths range from one meter to one decimetre.
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