Lamp with Single Switch Connection
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I.
Objective
After completing this
experiment, you are expected to be able to install a lamp with a single switch.
II.
Introduction
A switch is an
electrical device, usually electro-mechanical, used to control continuity
between two points. It can break an electrical circuit, interrupting the
current or diverting it from one conductor to another. There are many kinds of
switch such as switches for power installation, for lighting installation, etc.
But switches that we are most familiar with in our daily life at home, at
school and other community places are the lighting installation switches. One
of which is a single switch.
The main function of
these single switches is on/off a lamp. In this single switch, there are only
two contact points that connect the phase line with the lamp.
1) First, shut off the power to the
circuit—never work on an energized circuit. If you’re replacing an
existing switch, use a screwdriver to remove the plastic faceplate and to
unscrew the existing switch from the electrical box. Use an electrical tester
to check the wires that go to the existing switch (or the new wires that are
intended for the switch) so you can be sure they are not active. Place one
probe on the bare ground wire inside the box and touch the other probe on each
of the wired screw terminals of the switch or the bare end of the black wire
that will carry electricity to the switch. No voltage should register. Once
you’re sure the power is off to the switch, use the screwdriver to remove the
existing switch (if there is one) from its wires.
2) Straighten the ends of the circuit
wires you will be connecting to the switch, and then use wire
strippers to remove 1/2-inch of insulation from the wire ends.
3) Secure the circuit’s bare or green
grounding wire to the green grounding screw on the switch. If the
switch has its own grounding wire, twist the bare end together with the
circuit’s grounding wire, using lineman pliers, and secure it with a copper
compression sleeve or wire nut. Note: If you are using a metal box, include a
grounding jumper from the ground wire connections to the box.
4) Connect the two black wires
(sometimes called “hot” wires) to the switch’s screw terminals. It does not
matter which wire goes to which terminal. Note: Some switches have holes in the
back of the switch for the wires, which you can use instead of the terminal
screws on the side.
5) Mount the switch (be sure it’s
right side up). First, fold the wires behind the switch and carefully push the
switch into the box. Next, align the switch vertically by adjusting the screws
in the mounting slots. Also make sure the switch is flush with the wall. If it
isn’t, shim it out using the break-off portions of the switches plaster ears or
use special washers sold for shimming purposes. Screw the switch to the box.
6) Screw the faceplate to the switch
using the screws included with the faceplate.
In addition to wiring a switch of the single-pole
type, you can wire three-way switches that allow you to turn the light on and
off at two different locations, such as at either end of a hallway or
stairwell. It is also possible to wire a four-way switch that allows you to
control a light from three locations. Just remember the cardinal rule when
working with electricity: Make sure the power is turned off to the area you
are working on.
V.
Evaluation
1, Based on its capacity, 1mm is the minimum
crossing-sectional area for the copper wire.
2, Types of Switches
Any switch designed to be operated by a person is generally called a
hand
switch, and they are manufactured in several varieties:
Toggle switches are actuated by a lever angled in one of two or more
positions. The common light switch used in household wiring is an example of a
toggle switch. Most toggle switches will come to rest in any of their lever
positions, while others have an internal spring mechanism returning the lever
to a certain
normal position, allowing for what is called
"momentary" operation.
Pushbutton switches are two-position devices actuated with a button that is
pressed and released. Most pushbutton switches have an internal spring
mechanism returning the button to its "out," or
"unpressed," position, for momentary operation. Some pushbutton
switches will latch alternately on or off with every push of the button. Other
pushbutton switches will stay in their "in," or "pressed,"
position until the button is pulled back out. This last type of pushbutton
switches usually have a mushroom-shaped button for easy push-pull action.
Selector switches are actuated with a rotary knob or lever of some sort to
select one of two or more positions. Like the toggle switch, selector switches
can either rest in any of their positions or contain spring-return mechanisms
for momentary operation.
A joystick switch is actuated by a lever free to move in more than one axis
of motion. One or more of several switch contact mechanisms are actuated
depending on which way the lever is pushed, and sometimes by how
far it
is pushed. The circle-and-dot notation on the switch symbol represents the
direction of joystick lever motion required to actuate the contact. Joystick
hand switches are commonly used for crane and robot control.
Some switches are
specifically designed to be operated by the motion of a machine rather than by
the hand of a human operator. These motion-operated switches are commonly
called
limit switches, because they are often used to limit the motion
of a machine by turning off the actuating power to a component if it moves too
far. As with hand switches, limit switches come in several varieties:
These limit switches closely resemble rugged toggle or selector hand
switches fitted with a lever pushed by the machine part. Often, the levers are
tipped with a small roller bearing, preventing the lever from being worn off by
repeated contact with the machine part.
Proximity switches sense the approach of a metallic machine part either by a
magnetic or high-frequency electromagnetic field. Simple proximity switches use
a permanent magnet to actuate a sealed switch mechanism whenever the machine
part gets close (typically 1 inch or less). More complex proximity switches
work like a metal detector, energizing a coil of wire with a high-frequency
current, and electronically monitoring the magnitude of that current. If a
metallic part (not necessarily magnetic) gets close enough to the coil, the
current will increase, and trip the monitoring circuit. The symbol shown here
for the proximity switch is of the electronic variety, as indicated by the
diamond-shaped box surrounding the switch. A non-electronic proximity switch would
use the same symbol as the lever-actuated limit switch.
Another form of
proximity switch is the optical switch, comprised of a light source and
photocell. Machine position is detected by either the interruption or
reflection of a light beam. Optical switches are also useful in safety
applications, where beams of light can be used to detect personnel entry into a
dangerous area.
In many industrial processes, it is necessary to monitor various physical
quantities with switches. Such switches can be used to sound alarms, indicating
that a process variable has exceeded normal parameters, or they can be used to
shut down processes or equipment if those variables have reached dangerous or
destructive levels. There are many different types of process switches:
These switches sense the rotary speed of a shaft either by a centrifugal
weight mechanism mounted on the shaft, or by some kind of non-contact detection
of shaft motion such as optical or magnetic.
Gas or liquid pressure can be used to actuate a switch mechanism if that
pressure is applied to a piston, diaphragm, or bellows, which converts pressure
to mechanical force.
An inexpensive temperature-sensing mechanism is the "bimetallic
strip:" a thin strip of two metals, joined back-to-back, each metal having
a different rate of thermal expansion. When the strip heats or cools, differing
rates of thermal expansion between the two metals causes it to bend. The
bending of the strip can then be used to actuate a switch contact mechanism.
Other temperature switches use a brass bulb filled with either a liquid or gas,
with a tiny tube connecting the bulb to a pressure-sensing switch. As the bulb
is heated, the gas or liquid expands, generating a pressure increase which then
actuates the switch mechanism.
A floating object can be used to
actuate a switch mechanism when the liquid level in an tank rises past a
certain point. If the liquid is electrically conductive, the liquid itself can
be used as a conductor to bridge between two metal probes inserted into the
tank at the required depth. The conductivity technique is usually implemented
with a special design of relay triggered by a small amount of current through
the conductive liquid. In most cases it is impractical and dangerous to switch
the full load current of the circuit through a liquid.
Level switches can also be designed to detect
the level of solid materials such as wood chips, grain, coal, or animal feed in
a storage silo, bin, or hopper. A common design for this application is a small
paddle wheel, inserted into the bin at the desired height, which is slowly
turned by a small electric motor. When the solid material fills the bin to that
height, the material prevents the paddle wheel from turning. The torque
response of the small motor than trips the switch mechanism. Another design
uses a "tuning fork" shaped metal prong, inserted into the bin from
the outside at the desired height. The fork is vibrated at its resonant
frequency by an electronic circuit and magnet/electromagnet coil assembly. When
the bin fills to that height, the solid material dampens the vibration of the
fork, the change in vibration amplitude and/or frequency detected by the
electronic circuit.
Inserted into a pipe, a flow switch will detect any gas or liquid flow rate
in excess of a certain threshold, usually with a small paddle or vane which is
pushed by the flow. Other flow switches are constructed as differential
pressure switches, measuring the pressure drop across a restriction built into
the pipe.
Another
type of level switch, suitable for liquid or solid material detection, is the
nuclear switch. Composed of a radioactive source material and a radiation
detector, the two are mounted across the diameter of a storage vessel for
either solid or liquid material. Any height of material beyond the level of the
source/detector arrangement will attenuate the strength of radiation reaching
the detector. This decrease in radiation at the detector can be used to trigger
a relay mechanism to provide a switch contact for measurement, alarm point, or
even control of the vessel level.
Lamp
Connection with Single Switch and Junction Box
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I.
Objectives
After completing this experiment, you are
expected to:
1. Understand
the connection between a lamp, single switch, and junction box.
2. Understand
of the connection between a lamp, a single switch, and junction box.
II.
Introduction
An electrical Junction Box is a container for
electrical connections, usually intended to conceal them from sight and deter
tampering. The symbol of a junction box is shown at Figure (a), and Figure (c)
is its wiring diagram. Inside the junction box, there are three connection
points. One point is used as ground point and it is connected to the
installation grounding. The other two points are used as phase and neutral
line.
Standard colors used to different the cable
lines are:
Ground Line :
Green with yellow stripe cable.
Neutral Line :
Blue cable.
Phase Line :
Red, Black, and/or Yellow cable.
III.
Apparatus
Main :
Socket Lamp PTE-045-010 1 Unit
1 Phase MCB PTE-045-011 1 Unit
Single Switch PTE-045-015 1 Unit
Single Switch PTE-045-017 1 Unit
Connecting Leads
Auxiliary :
Incandescent Lamp 1 Unit
Other :
Junction box, Hammer, Phillips screwdriver, standard screwdriver, Wire
strippers, Wire strippers, Wire nuts, and Junction box cover
IV.
Procedure
Step 1
Determine the
size of box you need based on the wire size you wish to join. Junction boxes
sold at any home improvement retailer work for home projects.
Step 2
Mount the box
in place with the fasteners provided with it.
Step 3
Pull the wires
into the box leaving 6 inches of each wire hanging out the box, and then cut
off the excess.
Step 4
Cut away all
of the cabling’s outer jacket that is visible inside the junction box.
Step 5
Bring the
exposed copper wires together, twist their ends together in a clockwise motion
then cover then ends with a wire nut.
Step 6
Strip away 1
inch of the white wires insulation and then twist and cover with a wire nut.
Repeat the process with each color of wire.
Step 7
Push all of the
wires back inside the junction box and seal it with a junction box cover.
V.
Evaluation
1.
The
rules on installing a junction box.
-Check your
local electrical codes to know how many wires you are allowed to join in one
junction box.
-If working
with a metal junction box, affix a ground tail to it and then connect this to
the other exposed ground wires so the box itself is grounded.
-Ensure that
the power is off to the area where you are working by switching off the
breaker. Not doing this can result in serious injury or death to you and anyone
in the building. It is also a good idea to use a voltmeter to check that the
power is off before working near any exposed wires.
-Visually
verify that all of the wires are the same gauge before proceeding. Attaching
wires of different gauges is a fire hazard
2.
All
junction boxes have capacity associated with them in cubic inches. Most
non-metallic boxes on the home stores will have a Cubic Inch per Junction box
printed in them.
3.
4.
The
standard colors for line cables connected to the junction box socket are:
Ground Line : Green with yellow stripe cable
Neutral Line : Blue Cable
Phase Line : Red, Black, and/ or Yellow cable
Other sources
Each conductor Wires-Hot (black), red or
others not white or green), Neutral (White) and Ground (bare or green).
v
Correction
Power Factor for Fluorescent Lamp Circuit
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I.
Objectives
1.
Understand the
connection between fluorescent lamp
2.
Excess usage of
fluorescent lamp and incandescent lamp with the same power.
3.
Repair Power
Factor of Fluorescent lamp by using load capacitive.
II.
Introduction
Power Factor is a measure of how efficiently
electrical power is consumed. In the ideal world Power Factor would be unity.
Unfortunately in the real world Power Factor is reduced by highly inductive
load to 0.7 or less. This induction is caused by equipment such as lightly
loaded electric motors, luminaire transformers and fluorescent lighting
ballasts and welding sets, etc.
Apparent Power:
S= V.I
Reactive
Power: Q=I.V Sinφ
φ
Active Power: P=I.V Cosα
Where S=V.I (Volt Ampere)
P=V.I Cosφ (Watt)
Q=V.I Sinφ
III.
Apparatus
IV.
Procedure
V.
Evaluation
1.
Fluorescent
Bulbs Vs Incandescent Bulbs
While Fluorescent (CFL) bulbs
generate light by sending an electrical discharge through an ionized gas,
incandescent bulbs emit light by heating the filament present in the bulb.
When CFL bulbs were first introduced
in the 1970s, they were expected to spell the end of the traditional
incandescent light bulb. After all, they are much more energy-efficient.
Indeed, CFL bulbs have risen to promise in the last two decades. But owing to
their higher cost, taking longer to achieve full brightness and the environmental
concerns over bulbs that contain mercury, CFL bulbs have not yet made
incandescent light bulbs obsolete.
Advantages and Disadvantages
Fluorescent light
bulbs are better than incandescent bulbs in almost every way: lifetime cost,
environmental impact and energy savings.
Longevity
Fluorescent light
bulb is known to reduce replacement cost and is an energy saver. It also lasts
10 to 20 times longer than incandescent bulb. They do suffer from flickering
problems and shorter life if used at a place where it is frequently switched on
and off. These bulbs also require optimum temperatures to work well; they are
known to function under capacity when switched on in lower temperatures.
An incandescent
light bulb is very sensitive to changes in voltage and hence its longevity can
be double by adjusting the voltage supply. However, this affects the light
output and is known to be used only in exceptional circumstances
Energy Efficiency
Fluorescent bulbs
save energy and last longer, but are more expensive. These bulbs also convert
more of the electricity supplied into visible light than their popular
counterparts. Along with that, a fluorescent light bulb emits lesser heat and
distributes light evenly without putting a strain on the eyes.
Health Issues and Environmental
Impact
Though there hasn’t
been an official study, some people suggest that incandescent bulbs impose
lesser risks to the body than the fluorescent bulbs do. The fluorescent light
bulb is an energy saver so in the sense it is beneficial to the environment.
But it also harms the environment due to the mercury content in it. When these
lamps are disposed, the mercury content in them evaporates and causes air and
water pollution.
Incandescent bulbs
contain tungsten which is not hazardous to the environment. Hence, the bulbs do
not impose as much health risk as fluorescent bulbs do.
Price
When CFL bulbs were
first introduced, they were significantly more expensive than incandescent
bulbs. But now the price difference has virtually been wiped out. The cost
varies by manufacturer and retailer.
