IDMT Relay Tripping Time Calculator

Inverse definite minimum time (IDMT) relay is a form of overcurrent relay that operates in inverse time fashion with the current in the protection system. Basically, with the change in the peak value of the current, the time required for the relay to perform is decreased. The measurement of operating time starts immediately when the …

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Amps to Kilowatts Converter

During electrical power calculation, typically we use the normal calculator, in which sometimes we make mistakes during ac power calculations. Ac power consists of a power factor which we have to take into consideration. Again for three phase we have consider root 3 facor. This simple calculator will reduce the possibility of making an error …

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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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Buchholz relay

All About Buchholz Relay

Whenever a fault in the transformer develops slowly, heat is produced locally, which begins to decompose solid of liquid-insulated materials and thus to produce inflammable gas and oil flow. This phenomenon has been used in the gas protection relay or popularly known as Buchholz relay. This relay is applicable only to the so-called conservator type …

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grounding system

Electrical Grounding System Explained

Introduction: Power systems grounding is probably the most misunderstood element of any power systems design. Historically, the method of system grounding selected for various electrical system settings, e.g., industrial, commercial, etc., dates back to the early part of this century when only two methods were considered: solid grounded and ungrounded. Solid grounding with its advantage …

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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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