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Electrical Theory & Applications for HVACR
Glossary
Page 141
service entrance
the point of entry from the main electrical power line into the building
short circuit
an unintenƟonal connecƟon of low resistance resulƟng in excessive and oŌen damaging current flow
between two points in a circuit
single‐phase
describes a device that uses or produces only one alternaƟng current
slip
the difference between the speed of the rotaƟng magneƟc field of a motor and the actual rotor speed
SoŌ start
the use of a PosiƟve Temperature Thermistor (PTC) with or without a start capacitor connected in
series with the motor start winding.
solenoid
an electromechanical device that moves an iron core when energized
start winding
a winding which operates out of phase to help in starƟng a single phase electric motor
switch
a device that makes or breaks contacts to either complete or open a circuit
T
tag‐out
the pracƟce of labeling switches to inform others that repairs are in progress
terminal
a connecƟon point on an electrical device
three‐phase current
a combinaƟon of three alternaƟng currents that are 120 degrees different in phase
torque
twisƟng or rotaƟng force measured in inch or foot pounds
transformer
a device with two or more electromagneƟc coils, used to increase or decrease or isolate an AC voltage
transistor
a semiconductor used to perform switching or amplifying of electrical signals