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3/5 - Klockner Moeller
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... Directly from a PLC output: Using terminals A3 – A4 to connect to the PLC ...
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... On cars with full-current ammeters (mostly pre-1976 Chrysler products) it is best to take power from the alternator output terminal, rather than at the battery Positive (+) terminal. This so that when everything is in its 'normal' state (ie, engine running, battery charged) then the power for the he ...
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... in stator windings. This function may be used to protect generators connected to step-up transformers 100 % stator earth fault is a combination of two protection functions: b ANSI 59N/64G1: neutral voltage displacement, protection of 85 % to 90 % of the stator winding, terminal end. b ANSI 27TN/64G2 ...
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... The LIRW coverage pattern provides a 180o coverage area with a maximum coverage area of approximately 2100 square feet. The maximum sensing distance in front of the sensor is 40 feet, and 30 feet at each side. A “smallmotion” zone detects relatively small body movements and allows the lights to stay ...
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... feeder protection and control. The numerous features of numerical relays afford many functions that previously required single -function devices. For instance, typical hardware used in historic distribution feeder applications included single -phase overcurrent relays for phase and ground fault prot ...
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SC34 Discussion Session - Cigré Brasil

... compensate a transmission line and/or what are the challenges faced in the protection, control and monitoring of the capacitor banks as well as of the series compensated and adjacent transmission lines?  Question #2: What economic and/or environmental issues deter the implementation of series ...
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Elegance Electrician`s Guide
Elegance Electrician`s Guide

< 1 ... 33 34 35 36 37 38 39 40 41 ... 68 >

Protective relay



In electrical engineering, a protective relay is a device designed to trip a circuit breaker when a fault is detected. The first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as over-current, over-voltage, reverse power flow, over- and under- frequency. Microprocessor-based digital protection relays now emulate the original devices, as well as providing types of protection and supervision impractical with electromechanical relays. In many cases a single microprocessor relay provides functions that would take two or more electromechanical devices. By combining several functions in one case, numerical relays also save capital cost and maintenance cost over electromechanical relays. However, due to their very long life span, tens of thousands of these ""silent sentinels"" are still protecting transmission lines and electrical apparatus all over the world. An important transmission line or generator unit will have cubicles dedicated to protection, with many individual electromechanical devices, or one or two microprocessor relays.The theory and application of these protective devices is an important part of the education of an electrical engineer who specializes in power systems. The need to act quickly to protect circuits and equipment as well as the general public often requires protective relays to respond and trip a breaker within a few thousandths of a second. In these cases it is critical that the protective relays are properly maintained and regularly tested.
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