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Electrical Theory & Applications for HVACR
Glossary
Page 127
Glossary
A
alternaƟng current (AC)
electrical voltage and current that changes in magnitude and direcƟon in a cyclic characterisƟc; AC
electricity in North America cycles 60 Ɵmes per second
ammeter
an instrument used to measure current flow through a circuit
ampere
a unit of current flow equal to one coulomb of charge moving through a circuit in one second
analog meter
a meter that displays informaƟon using a needle moving over a scale
anode
posiƟve terminal of an electrical device
atom
the smallest unit of an element, made up of protons, electrons and neutrons, (except hydrogen)
B
BriƟsh thermal unit (Btu)
a unit of energy based on the amount of heat required to raise the temperature of one pound of
water one degree Fahrenheit
C
capacitance
a measure of the energy stored in a capacitor; units of capacitance are farads
capacitor
a device made with two conducƟve plates separated by a dielectric used to increase an inducƟve load
efficiency by changing the phase angle and electrostaƟcally stores electrical energy
capacitor‐start motor
a modificaƟon of a split‐phase motor that uses a capacitor in series with the start winding; the
capacitor causes a phase displacement for starƟng
capacitor‐start inducƟon‐run motor
a motor in which the capacitor assists start under high load condiƟons; once started, the motor
operates on the run winding only