Test Instruments & Measuring Devices
OTHER ELECTRICAL MEASURING DEVICES
OTHER ELECTRICAL MEASURING DEVICES
Other measuring devices are used to aid operators in determining the electric
plant 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 of
the following in-place measuring devices:
e.
Ampere-hour meter
f.
Power factor meter
g.
Ground detector
h.
Synchroscope
EO 1.3
EXPLAIN how the following electrical test equipment
and measuring devices are connected to a circuit:
e.
Ampere-hour meter
f.
Power factor meter
g.
Ground detector
h.
Synchroscope
Ampere-Hour Meter
The ampere-hour meter registers ampere-hours and is an integrating meter similar to the
watt-hour meter used to measure electricity usage in a home. Typical ampere-hour meters are
digital indicators similar to the odometer used in automobiles. The ampere-hour meter is a direct
current meter that will register in either direction depending on the direction of current flow. For
example, starting from a given reading, it will register the amount of discharge of a battery; when
the battery is placed on charge, it will operate in the opposite direction, returning once again to
its starting point. When this point is reached, the battery has received a charge equal to the
discharge, 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 charge
direction. These meters are subject to inaccuracies and cannot record the internal losses of a
battery. They attempt to follow the charge and discharge, but inherently do not indicate the
correct 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 largely
superseded by the voltage-time method of control.
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