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Circuit Control Devices
A.
Bhatia
Overview
Circuit control
in its simplest form, is the application and removal of power. This can also be expressed as turning a circuit on and off or
opening and closing a circuit. Before you learn about the application
of circuit control devices, you should know why circuit
control is needed. If a circuit develops problems
that could damage the equipment or endanger personnel, it should be
possible to remove the power from that circuit. The circuit
protection devices (fuses and breakers) are not the control devices;
these are protection devices that will remove power
automatically in event of overload conditions. Circuit
control devices allow you to turn the device ON when
it is needed and OFF when it is not needed.
There are
three type of common circuit control devices; switches, relays and solenoids.
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A switch, in
simple terms, contains two metal pieces called contacts that touch to make a
circuit and separate to break the circuit.
Switches can
be classified according to the arrangement of their contacts.
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Relays are protective, or
control, devices, which complete or break an electrical circuit in response to
electrical changes in an external circuit.
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Solenoids consist of one or
more coils surrounding an iron core. The coil(s) and the core are moveable in
relation to each other. The axial or rotary movement is a result of the
magnetic flux of the coil. It is designed to convert electrical energy into
mechanical energy.
This 3-hr course provides general requirements,
classifications, installation, maintenance, testing, and application information
for circuit control devices, and covers the requirements for switches, relays
and solenoids. The course is
based entirely on Naval
Education and Training Materials (NAVEDTRA
14175),
Electricity and Electronic Training Series;
Module-3 and covers Chapter 3 titled “Circuit Control Devices”.
The student must take a multiple-choice quiz consisting of
fifteen (15) questions at the end of
this course to obtain PDH credits.
Specific Knowledge or Skill Attained
This course teaches the following specific knowledge and
skills:
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The reasons for
providing circuit control devices
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Three general types
of circuit control devices
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The schematic
symbols for a switch, solenoid and relay
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The difference
between a manual and an automatic switch and the reason why multi-contact
switches are used
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The type of switch
used to prevent the accidental energizing or de-energizing of circuit
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The meaning of the
current and voltage rating of a switch
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The operating
principle of a solenoid and how to check a solenoid for proper operation
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The operating
principle of a relay and how it differs from a solenoid
Course
Click on the following PDF attachment and review the document prior to taking
a quiz for credit.
Circuit Control Devices (497 KB)
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To obtain PDH credits for this course, you will need to take a quiz for
credit. Click on the link below.
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