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Panelboard |
A single panel or group of panel units designed
for assembly in the form of a single panel, including buses and
automatic overcurrent devices, and equipped with or without
switches for the control of light, heat, or power circuits;
designed to be placed in a cabinet or cutout box placed in or
against a wall, partition, or other support; and accessible only
from the front.
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Peak Value |
The highest or maximum value of an alternation
of alternating current or voltage. This peak value occurs twice
during each cycle.
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Peak-to-Peak Value |
The maximum voltage change occuring during one
cycle of alternating voltage or current. The total amount of
voltage between the positive peak and the negative peak of one
cycle or twice the peak value.
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Period |
The
time required for the current to pass through one cycle.
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Phase |
The
factional part of the period of a sinusoidal wave, usually
expressed in electrical degrees and referenced to the origin.
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Phase Angle |
(See
"Phase Difference")
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Phase
Difference |
The
difference in phase between two sinusoidal waves having the same
period, usually expressed in electrical degrees. The voltage
wave if generally taken as the reference, so in an inductive
circuit the current lags the voltage, and in a capacitive
circuit the current leads the voltage. Sometimes called the
phase angle.
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Plenum |
A compartment or chamber to which one or more
air ducts are connected and that forms part of the air
distribution system.
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Polyphase |
A general term applied to any system
of more than a single phase. This term is ordinarily applied to
symmetrical systems.
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Potential
Transformer |
A transformer designed for shunt or
parallel connection in its primary circuit, with the ratio of
transformation appearing as a ratio of potential differences.
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Power |
Rate of work, equals
work divided by time.
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Power Factor |
Watts divided by voltamps (VA), KW divided by
KVA. Power factor: leading and lagging of voltage versus current
caused by inductive or capacitive loads, and 2) harmonic power
factor: from nonlinear current.
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Power Outlet |
An enclosed assembly that may include
receptacles, circuit breakers, fuseholders, fused switches,
buses, and watt-hour meter mounting means; intended to supply
and control power to mobile homes, recreational vehicles, park
trailers, or boats or to serve as a means for distributing power
required to operate mobile or temporarily installed equipment.
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Premises Wiring (System) |
That interior and exterior wiring, including
power, lighting, control, and signal circuit wiring together
with all their associated hardware, fittings, and wiring
devices, both permanently and temporarily installed, that
extends from the service point or source of power, such as a
battery, a solar photovoltaic system, or a generator,
transformer, or converter windings, to the outlet(s). Such
wiring does not include wiring internal to appliances,
luminaires (fixtures), motors, controllers, motor control
centers, and similar equipment.
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Primary |
The
windings of a transformer which receive energy from the supply
circuit.
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Pulsating Current. |
Direct
current which changes regularly in magnitude.
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