Engineering Applications Electricity and Electronics I Terminology Terms For Test #4

Engineering Applications

Electricity and Electronics I

Terminology

Terms

For Test #4


1.

contactors
–

a device for repeatedly connecting and interrupting an electric power

circuit. Auxiliary
contacts are usually provided in addition to the main power

conta
cts.


2.

control contacts
–

contacts in a circuit used to control the delivery of power to

motors.


3.

eutectic alloy solder
–

a type of alloy that has a very low melting point and

quickly becomes solid when
heat is removed.


4.

jogging
–

frequent starting and stop
ping of a motor for short periods of time.


5.

magnetic flux
–

the lines of force that exist about a magnetic body and collectively

constitute a
magnetic field.


6.

motor control
–

a broad term used to describe any device that controls the

operation of an electr
ic
motor.


7.

motor starters
–

a type of controller which is designed to start a motor. Motor

starters may include
overload protection devices.


8.

plugging
–

to stop a motor by reconnecting it so that it tries to turn in the oppo
s
ite

direction.


9.

relays
–

a devi
ce that responds to input conditions by making or breaking contacts.


10.

reversing starter
–

a type of controller used for reversing the rotation of the motor

shaft.


11.

sequence control
–

automatic and orderly control of a series of operations.


12.

solenoids
–

a c
oil of wire that, when energized, acts as a magnet and will pull a

moveable iron core or
armature to a new position.


13.

sump
–

a pit or reservoir for draining or holding liquids.


14.

conduction
–

the transfer of cold or heat through a substance.


15.

control relays

–

an auxiliary device used to switch control circuits and large

starter coils.


16.

convection
–

the transfer of cold or heat through radiation.


17.

latching relay
–

a relay that is designed to maintain contacts by using a

mechanical latch, which can be
released

either mechanically or electrically.


18.

orifice
–

an opening or hole.


19.

timing relay
–

a relay that can be energized and de
-
energized at variable time

intervals.


20.

brushes
–

a conductive metal or carbon block that makes contact with a turning

armature.


21.

commu
tator
–

a circular arrangement of bars or segments that are insulated from

each other and the
rotor of a DC motor.


22.

induction motors
–

an ac motor where the primary winding on one part (usually

the stator) is connected
to the power source and the secondary

winding on the other

part (usually the rotor) carries an induced
current. These currents produce an

opposite
-
polarity magnetic field in the rotor and the stator. The
attraction between

the opposite stator and rotor magnetic fields produces torque and caus
es the motor

to
turn.