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Electromechanical protective relays at a hydroelectric generating plant. The relays are in round glass cases. The rectangular devices are test connection blocks, used for testing and isolation of instrument transformer circuits. In electrical engineering, a protective relay is a relay device designed to trip a circuit breaker when a fault is ...
A small cradle relay often used in electronics. The "cradle" term refers to the shape of the relay's armature. If the relay is driving a large, or especially a reactive load, there may be a similar problem of surge currents around the relay output contacts. In this case a snubber circuit (a capacitor and resistor in series) across the contacts ...
Buchholz relays have a test port to allow the accumulated gas to be withdrawn for testing. Flammable gas found in the relay indicates some internal fault such as overheating or arcing, whereas air found in the relay may only indicate low oil level or a leak. [3] Through a connected gas sampling device the control can also be made from the ground.
As such, safety relays monitor a specific function. When connected to other safety relays, they guarantee full monitoring of a plant or machine. [1] They meet the requirements of EN 60947-5-1, EN 60204-1 and VDE 0113-1. [5] Furthermore, there are many variants of safety relays, which are suitable for various machinery applications.
In electrical engineering, a stepping switch or stepping relay, also known as a uniselector, is an electromechanical device that switches an input signal path to one of several possible output paths, directed by a train of electrical pulses. The major use of stepping switches was in early automatic telephone exchanges to route telephone calls ...
Armature reaction is essential in amplidyne rotating amplifiers. Armature reaction drop is the effect of a magnetic field on the distribution of the flux under main poles of a generator. [5] Since an armature is wound with coils of wire, a magnetic field is set up in the armature whenever a current flows in the coils.
A wire spring relay is a type of relay, that has springs made from drawn wires of nickel silver, rather than cut from flat sheet metal as in the flat-spring relay. This class of relays provided manufacturing and operating advantages over previous designs. Wire spring relays entered mass production in the early 1950s. [1] [2]
A power plant using coal, oil, or natural gas fuel. Fourier series A set of coefficients of sine and cosine waves; this can represent a time function as a function of frequency. Fourier transform An algorithm for converting a continuous waveform in the time domain into an equivalent set of spectral components in the frequency domain.