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60947-4-2 AC-58b The control of a hermetically sealed refrigeration compressor motor with automatic reset of the overload trips: Intermittent operation 60947-4-2 AC-140 Control of small electromagnetic loads with holding current ≤ 0.2 A; e.g. contactor relays 60947-5-2 A: Protection of circuits, with no rated short-time withstand current ...
Brown, Boveri & Cie. (Brown, Boveri & Company; BBC) was a Swiss group of electrical engineering companies. It was founded in Baden bei Zürich, [1] in 1891 by Charles Eugene Lancelot Brown and Walter Boveri who worked at the Maschinenfabrik Oerlikon.
ABB Group [6] is a Swedish-Swiss [7] [8] [9] multinational electrical engineering corporation. Incorporated in Switzerland as ABB Ltd., and headquartered in Zurich, [1] it is dual-listed on the SIX Swiss Exchange in Zurich and the Nasdaq Nordic exchange in Stockholm, Sweden, in addition to OTC Markets Group's pink sheets in the United States. [10]
[7] [8] On a 3-phase circuit, a recloser is more beneficial than three separate fuse cutouts . For example, on a wye to delta conversion, when cutouts are used on the wye side and only 1 out of 3 of the cutout fuses open, some customers on the delta side have a low voltage condition, due to voltage transfer through the transformer windings .
Following strong initial uptake, ABC lost ground in the 1990s compared to alternative metrics, such as Kaplan's balanced scorecard and economic value added.An independent 2008 report concluded that manually driven ABC was an inefficient use of resources: it was expensive and difficult to implement for small gains, and a poor value, and that alternative methods should be used. [4]
Electromechanical protective relays operate by either magnetic attraction, or magnetic induction. [9]: 14 Unlike switching type electromechanical relays with fixed and usually ill-defined operating voltage thresholds and operating times, protective relays have well-established, selectable, and adjustable time and current (or other operating parameter) operating characteristics.
The sequence of events is similar for manual or automatic synchronization. The generator is brought up to approximate synchronous speed by supplying more energy to its shaft - for example, opening the valves on a steam turbine, opening the gates on a hydraulic turbine, or increasing the fuel rack setting on a diesel engine. The field of the ...
Motor control centers are usually used for low voltage three-phase alternating current motors from 208 V to 600 V. Medium-voltage motor control centers are made for large motors running at 2300 V to around 15000 V, using vacuum contactors for switching and with separate compartments for power switching and control.