Catalog of Electrical Engineering questions with useful answers that help you develop a clear insight of your conceptual problems.
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Transformer-Rated indicates that the meter measures a scaled-down representation of the load, achieved by using external current transformers (CTs) and optional voltage transformers (VTs or PTs). Abbreviated by the letters “TR.”
VTR stands for Voltage Transformer Ratio. VTR specifically refers to the ratio between the primary voltage and the secondary voltage in a voltage transformer (potential transformer or PT). The voltage transformer ratio is crucial for accurately stepping down or reducing high voltages to a level suitable for measurement and protection devices.
Test Amps are the current in amps that the meter is tested for “Full Load (FL) accuracy,” abbreviated by the letters “TA” (15% of CL).
Kh represents the watt-hour constant, indicating the number of watt-hours represented by each disk revolution on an electromechanical meter or one pulse of serial data.
Light Load is the current in amps that the meter is tested for low current accuracy, typically 10% of TA, abbreviated by the letters “LL.”
The Form Letter in Instrumentation and Metering Engineering is the letter following the form number, indicating the socket/terminal configuration of the meter.
The term elements in Instrumentation and metering Engineering refers to the combination of a voltage-sensing unit and a current-sensing unit, providing an output that is proportional to the power measured.
Automatic Meter Reading abbreviated as AMR is defined as the reading of meters from a location remote from where the meter is installed. Technologies such as telephone circuits, radio transmission, and power line communication are used for AMR.
The terms Class in reference to instrument transformers and meters is defined as the maximum continuous current the meter is capable of handling, abbreviated by the letters “CL.” Common meter class ratings as defined by IEEE are below: Class What it implies CL 100 100 A—Self-contained CL 200 200 A—Self-contained CL 320 320 A—Self-contained CL … Read more
Burden is defined as the load placed on an instrument transformer secondary circuit by metering (or other) equipment. It is expressed in volt-amperes at a specific power factor.