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Ideally the measuring device should not affect the circuit parameters i.e., the internal impedance of the ammeter should be zero (no voltage drop over the ammeter) and the internal impedance of the voltmeter should be infinite (no current through the voltmeter). However, in actual case, ammeters have a low but non zero impedance and voltmeters ...
A high-voltage current transformer may contain several cores, each with a secondary winding, for different purposes (such as metering circuits, control, or protection). [7] A neutral current transformer is used as earth fault protection to measure any fault current flowing through the neutral line from the wye neutral point of a transformer.
Classes are denoted by either a letter or percentage. For example, Class B is a temperature accuracy from IEC-751 that requires accuracy of ± 0.15 degrees Celsius. Class 0.5 is an ANSI C12.20 accuracy class for electric meters with absolute accuracy better than ± 0.5% of the nominal full scale reading. [1]
Wire crossover symbols for circuit diagrams. The CAD symbol for insulated crossing wires is the same as the older, non-CAD symbol for non-insulated crossing wires. To avoid confusion, the wire "jump" (semi-circle) symbol for insulated wires in non-CAD schematics is recommended (as opposed to using the CAD-style symbol for no connection), so as to avoid confusion with the original, older style ...
The reference designator usually consists of one or two letters followed by a number, e.g. C3, D1, R4, U15. The number is sometimes followed by a letter, indicating that components are grouped or matched with each other, e.g. R17A, R17B. The IEEE 315 standard contains a list of Class Designation Letters to use for electrical and electronic ...
A current transformer (CT) is a series connected measurement device designed to provide a current in its secondary coil proportional to the current flowing in its primary. Current transformers are commonly used in metering and protective relays in the electrical power industry.
A schematic representation of long distance electric power transmission. From left to right: G=generator, U=step-up transformer, V=voltage at beginning of transmission line, Pt=power entering transmission line, I=current in wires, R=total resistance in wires, Pw=power lost in transmission line, Pe=power reaching the end of the transmission line, D=step-down transformer, C=consumers.
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