Test Instruments & Measuring DevicesOTHER ELECTRICAL MEASURING DEVICESOTHER ELECTRICAL MEASURING DEVICESOther measuring devices are used to aid operators in determining the electricplant conditions at a facility, such as the ampere-hour meter, power factor meter,ground detector, and synchroscope.EO 1.2 STATE the electrical parameters measured by each ofthe following in-place measuring devices:e. Ampere-hour meterf. Power factor meterg. Ground detectorh. SynchroscopeEO 1.3 EXPLAIN how the following electrical test equipmentand measuring devices are connected to a circuit:e. Ampere-hour meterf. Power factor meterg. Ground detectorh. SynchroscopeAmpere-HourMeterThe ampere-hour meter registers ampere-hours and is an integrating meter similar to thewatt-hour meter used to measure electricity usage in a home. Typical ampere-hour meters aredigital indicators similar to the odometer used in automobiles. The ampere-hour meter is a directcurrent meter that will register in either direction depending on the direction of current flow. Forexample, starting from a given reading, it will register the amount of discharge of a battery; whenthe battery is placed on charge, it will operate in the opposite direction, returning once again toits starting point. When this point is reached, the battery has received a charge equal to thedischarge, and the charge is stopped. It is normally desired to give a battery a 10% overcharge.This is accomplished by designing the ampere-hour meter to run 10% slow in the chargedirection. These meters are subject to inaccuracies and cannot record the internal losses of abattery. They attempt to follow the charge and discharge, but inherently do not indicate thecorrect state of charge. Similar to an ammeter, the ampere-hour meter is connected in series.Although the ampere-hour meters were used quite extensively in the past, they have been largelysuperseded by the voltage-time method of control.Rev. 0 Page 23 ES-14
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