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thermal overload relays

Why is both RTD temperature and thermal overload protection needed?

Although both methods give protection against overload and thermal┬árise, both have own pros and cons. Especially with the important objects, both methods are used because they complement each other. RTD basics A fundamental physical property of a metal is that its resistivity changes with temperature. For many metals, this relationship is quite linear over wide …

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Protection relay codes

Introduction: Numerical codes are sometimes used when defining the protection relay, whereas in other cases symbols are used. The numerical codes refer to the IEEE C37-2 Standard, whereas the symbols refer to the IEC Standards. In the definition of the symbols the IEC Standards have not detailed all the symbols to be used and so …

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All About Induction Machines

Introduction Induction machines, also called asynchronous machines, can be used as generators or motors. Induction machines can be either of one or three-phase construction. The following discussion focuses on the three-phase machines and their properties. The maximum of the applications for three-phase induction machines is with power ranges varying from a few kilowatts to a …

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Electrical characteristics

(Peak) making current: The peak value of the first major loop of the current in one pole of a switching device during the transient period following the initiation of current during a making operation. Peak current: The peak value of the first major loop of current during the transient period following initiation. Breaking current: Current …

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