Electrical Engineers and Master Electricians (EEAME) Portal
Home
Dictionary
Tutorials
General
Specifications
Forums
Disclaimer
Devices
Dictionary of Electrical Engineering
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
ALL
Commonly used terms in the Electrical industry.
core-type transformer
a transformer in which the magnetic circuit upon which the windings are wound takes the form of a single ring. When the coils are placed on the core, they encircle the core.
See
core
corona effect
flow of electrical energy from a high-voltage conductor to the surrounding ionized air. This effect only becomes significant for potentials higher than 1000 V. This effect is characterized by a faint glow, a crackling noise and conversion of atmospheric oxygen to ozone.
corona resistance
capacity of a material to bear the action of the corona effect. This capacity is particularly important for polymeric materials, which have to withstand the chemical degrading effect promoted by ozone generated by the corona effect.
See
corona effect
counter-EMF
a voltage developed in an electrical winding by Faraday's Law that opposes the source voltage, thus limiting the current in the winding.
counter-EMF starter
a type of DC-motor starter that reduces the resistance in the starting circuit as the voltage across the armature rises.
counter-torque
torque developed in opposition to the rotation of a machine. It is produced as load current flows in the presence of and perpendicular to magnetic flux in a machine that is generating electric power.
counterpoise
a ground wire buried beneath an overhead line to lower footing impedance.
counterpoise ground
buried conductor routed under transmission lines designed to achieve low earth electrode resistance.
coupled line filter
a type of microstrip or stripline filter that is composed of parallel transmission lines. Bandwidth is controlled by adjusting the transmission line spacing. Wider bandwidths are obtained by tighter coupling. A two-port circuit is formed by terminating two of the four ports in either open or short circuits, which leaves ten possible combinations. Different combinations are used to synthesize low-pass, bandpass, all pass, and all stop frequency responses.
crest factor
the ratio of the peak value of a signal to its RMS value.
critical clearing angle
(1) following a balanced three-phase fault at the stator terminals of a synchronous machine, the maximum value of the angular position of the rotor prior to the removal (clearing) of the fault such that the rotor will obtain synchronous speed without slipping poles following the removal (clearing) of the fault. The corresponding time for the rotor to achieve this angle is specified as the critical clearing time.
(2) the largest allowable angular deviation from synchronism that may be borne by a power system such that the system remains stable: the edge of instability.
CT
See
current transformer
cumulatively compounded
a compound-wound DC machine in which the flux produced by the MMF of the shunt field winding and the flux produced by the MMF of the series field winding are in the same direction.
current
the flow of charge, measured in amperes (1 ampere = 1 coulomb/s).
current density vector field
the field (commonly denoted J ) that is related to the electric field intensity vector field by the conductivity of the medium that the fields are located in. One of the quantities found on the right side of Ampere's Law. The units are (amperes/square meter).
current distribution factor
in economic dispatch studies, the proportion of a power line's total current which is contributed by a particular generating plant.
current limiting
the output current is limited to a preset level even under a shorted output condition. This can be accomplished by reducing the output voltage to prevent the current limit from being exceeded.
current limiting fuse
a fuse that limits the level of fault current from that which is available. It operates by developing a substantial voltage across the fuse following the melting of the fuse element.
current regulator
a device used to control the magnitude and phase of the current in DC, AC or other electrical variable speed drives. May use different control strategies like hysteresis current control or ramp comparison current control.
current transducer
a device used to measure current in a variety of applications including variable speed drives. May give out a current proportional to the measured current or a voltage proportional to the measured current. Electrical isolation may be obtained by using a current transformer (cannot be used at DC) or a hall effect transducer that can be used down to DC.