In the near future, wind energy will be the most cost
effective renewable source of electrical power. In fact, a good case can be
made for saying that it has already achieved this status. By 2050 except coal
all other fossil fuel sources (oil & gas) will be depleted.
Wind
energy has a fundamental advantage over traditional solar power, however in
that its energy is more and the wind being available in a mechanical form is
easily converted to useful work.
The major technology developments
enabling wind power commercialization have already been made. India has been working
well in wind energy. They have taken a master plan to generate 1200MW power
from the wind mills.
A windmill
is a machine with rotating blades that is designed to convert the energy of the
wind into more useful forms. Most modern windmills, more appropriately called
wind turbines, are used to generate electric power. Generation of electricity
by the kinetic energy of wind requires a minimum average wind speed of 21.6
km/hr, which equals 11.67 knots (1 knot = 1.85 km/hr). In Bangladesh
there are some coastal areas which have similar wind power to install a wind
mill. Compared to other renewable energy wind mill is most familiar in the
world because in the most of the country of the world like Denmark, USA, UK, Sweden, Netherland, Argentina,
Bulgeria, Kenya, are established in wind
mill. India
has done better in wind mill.
Wind data from Bangladesh Meteorological Department and
different previous and ongoing wind resource assessment projects are briefly
described in the subsequent sections.
1.2.1 Advantages:
·This energy is the least expensive. It is
available round the clock.
·It doesn't cause any pollution like power plants
do. Power plants depend on the combustion of fossil fuels which can pollute the
air.
·Windmill generators do not give off atmospheric
emissions that can cause acid rain and greenhouse affect.
·As wind turbines are usually built on ranches
and farms, these places benefit most from them. Farm owners get rent payment from
the power plant owners and at the same time, they can continue to work on their
property since these turbines only use a portion of the land.
·One of the greatest advantages of wind energy is
that it is simple and renewable. The cost of producing wind energy has come
down by at least eighty percent since the eighties. Along with economy, Wind
Energy is also said to diminish the greenhouse effect.
·One other advantage of wind energy that it is
readily available around the clock. Wind energy may be the answer to the
globe's question of energy in the face of the rising petroleum and gas prices.
·Before the invention of steam engine wind energy
was extensively used in boats, ships etc.
1.2.2
Characteristics of Wind Power:
1.
Wind power systems are non-polluting
2.
It is a renewable source of energy
3.
The energy generated by wind power systems it cheaper
4.
Wind energy system avoid fuel provision and transport
1.2.3
Wind Energy Source:
All referable energy ultimately comes from
the sun about 1-2% of sun’s energy that received by the earth is converted to
wind energy. A wind turbine obtains its power by converting the force of the
wind into torque acting on the rotor blades.
Biogas may be the most promising renewable energy resource
for Bangladesh.
Presently there are tens of thousands of households and village-level biogas
plants in place throughout the country. Biogas units are of three major types:
floating cover, fixed cover, and plastic bag plants. Of these models, the fixed
cover (dome) model has become very popular and units are disseminated
throughout the country by the Institute of Fuel Research & Development
(IFRD) of BCSIR. These is a real Potential to harness basic biogas technology rural
electrification, via village-level biogas production and internal combustion
(or even micro turbine) power generation. Such an arrangement would have the
added value of providing some self-sufficiency to rural populations during
periods of power shortfalls and load shedding.
Micro-hydro and Mini-hydro have limited application in
Bangladesh, with the exception of Chittagong and Chittagong Hill tracts.
Previous hydropower assessments have identified a handful of possible sites
from 10 KW to 5 MW; however, no appreciable capacity has been installed. There
is one large hydro facility in the country at Kaptai, installed in the 1960s
and producing 230 MW (Three unit of 50 MW and four unit of 20 MW).
1.3.3
Bio-diesel energy
Bio-diesel may also be one of the promising sources of energy
in Bangladesh.
Government ofBangladesh
has taken necessary steps for Jatropha plantation, a source of Bio-diesel. A
Pilot projecthas already been considered to verify its commercial
viability. This may be a potential source ofrenewable energy.
Biomass is the most significant
energy source in Bangladesh
which accounts for 70% of the total final energy consumption in Bangladesh. The
main sources of biomass fuels are
Trees (wood fuels,
twigs, leaves, plant residues)
Agricultural
Residues (paddy husk, bran, bagasse, jute stick etc.) and
Livestock
(animal dung).
Land use pattern and different biomass fuels of Bangladesh are
described below in separate subsections. Approximate land use pattern of the
country is
Geothermal energy is the natural heat of the Earth. It is a
renewable source of energy if the exploration process doesn’t hamper the
ecosystem or emit greenhouse gases. Geothermal reservoirs that are close enough
to the surface to be reached by drilling can occur in places where geologic
processes have allowed magma to rise up through the crust, near to the surface,
or where it flows out as lava. The crust of the Earth is made up of huge
plates, which are in constant but very slow motion relative to one another.
Magma can reach near the surface in three main geologic areas:
Where
Earth's large oceanic and crystal plates collide and one slides beneath
another, called a subduction zone The best example of these hot regions
around plate margins is the Ring of Fire and the areas bordering the
Pacific Ocean: the South American Andes, Central America, Mexico, the
Cascade Range of the U.S. and Canada, the Aleutian Range of Alaska, the
Kamchatka Peninsula of Russia, Japan, the Philippines, Indonesia and New
Zealand.
Spreading
centers, where these plates are sliding apart (such as Iceland,
the rift valleys of Africa, the
mid-Atlantic Ridge and the Basin and RangeProvince
in the U.S.A.).
Places
called hot spots fixed points in the mantle that continually produce magma
to the surface.
Because the plate is continually moving across the hot spot,
strings of volcanoes are formed, such as the chain of Hawaiian
Islands. There is a known hot salt water spring, known as
Labanakhya, in Bangladesh
at 5 kilometer to the north of Sitakunda (40 kilometer from Chittagong). Possibility of extracting energy
from this site or any other unknown sites can be investigated by Satellite
Remote Sensing or Physical Surveys.
Bangladesh
has got 710 km (441 mi) long coastal belt along the Bay
of Bengal. If the marine RETs become viable option in the future,
then the country may harness energy from marine RETs. The main marine RETs are
DC Brushed motors have been used in the RC hobby from the beginning
of electric flight. Until recently, the only electric motor typically
found on model trains, planes, cars and boats was a DC brushed motor.
For reference, the term “brushed” simply means that there is
something (brushes) touching the rotor (commutator) in order to form an
electrical circuit between the battery and the armature coil windings
(the copper wires you see inside). The armature is mounted to the steel
axle and has multiple coil windings attached, each providing an
electromagnetic force when energized by the current flowing from the
brushes through the commutator.
The commutator is made of multiple contact surfaces wired to each coil
so that the brushes are “handing off” energy to the next coil in order
to maintain rotation of the rotor. Each rotation hands the coils off to
the opposite brush which means each armature coil is energized creating
magnetic attraction, pulling itself towards the next permanent magnet.
The motor housing has fixed, permanent magnets of opposite poles mounted
around the spinning armature. This sets the stage for a consistent
magnetic environment for which the armature coils can either push or
pull, creating rotation.
Airplane Use
Pros and Cons:
Inexpensive Performance degrades over time Easy to wireHigher resistance than brushless Electronic Speed Controls (ESCs) are cheaperLess powerful than brushless Can be “ganged” together in parallel and powered by the same ESCHeavier than brushless counterpart
Common Types
Canned/Can Motors
The picture above is of a typical “canned” motor. Canned motors are
usually included in a kit, are very inexpensive, use lower strength
ferrite permanent magnets, plastic or porous brass bearings and are
non-serviceable. They will fly the model they were supplied with just
fine but if you want to get higher performance out of your airplane, you
can upgrade to a brushed motor with higher quality components and,
specifically, better magnets and brushes or even move into a brushless
configuration.
Rare Earth Motors
Rare earth motors commonly use Cobalt or Neodymium magnets to achieve
much higher performance than their ferrite counterparts. Another added
advantage is that Cobalt and Neodymium experience less performance
degradation than Ferrite as temperatures increase.
Rare earth brushed motors are made of better materials all around, such as:
Better cases with improved heat dissipation
Roller bearings for reduced friction
Replaceable brushes for longer overall serviceable life
Higher quality components with better conductivity and less wear
General Considerations
An unfortunate characteristic of magnets is that they lose strength
the hotter they get. Higher quality magnets perform better in higher
temperatures but also cost significantly more.
You can install a heat sink over the motor housing (avoid covering
air holes) to help dissipate heat and maintain performance. Check for
proper clearance before mounting; heat sinks require more room than the
stock motor alone. The following image is a typical slip-on heat sink
for an electric motor.
Another unfortunate characteristic related to brushed motors is that the
brushes and commutator break contact during rotation. This results in a
loss of energy transferred to each stator coil. This also causes all
of the stored electrical energy to “arc”, resulting in Radio Frequency
Interference (RFI). This electrical “noise” can wreak havoc on your
radio receiver and even your servos. 2.4 GHz radios operate outside of
the susceptible frequency range but you can still get interference to
your other components.
The effective use of a capacitor on each motor lead can isolate or
“buffer” this condition and reduce or eliminate any interference the
motor is generating. Some motors already have capacitors installed
internally but you should always investigate before launching your model
and losing control! There is more information regarding interference
in the Radio Systems section and the break-in section below.
Wiring
**Always use caution and keep your hands and all other
objects out of the path of a moving prop. These seem like toys but
smaller models can remove finger tips and larger models can actually
amputate fingers and even cause death**
One of the benefits of a brushed DC motor is that it uses only two
wires to operate. As conventional as it seems, you have a positive and
negative lead from the Electronic Speed Control (ESC) that provided
variable current to the motor for proportional (gradual) control from
idle to full speed. Connections are polarity sensitive and in order to
get the correct rotational direction you may have to reverse the leads
from the ESC going to the motor NOT FROM THE BATTERY TO THE ESC!!!.
Connect the esc to the motor without the prop installed (safest) and
gently increase the throttle to see which way it is turning. If it is
turning in the wrong direction, power off, reverse the two wires, and
reconnect. The illustration above shows a brushed DC motor properly
connected to an ESC, connected to a battery and radio receiver.
As the old saying goes with gas engines: “Break it in, or [you'll]
break it down!” While it’s nothing quite that extreme with electric
motors, a properly broken-in brushed DC motor will give many hours of
cooler, more efficient and more powerful operation. Breaking-in a motor
refers to “seating” the brushes properly on the commutator. The goal
is to gently wear the brushes against the commutator in order to achieve
a smooth fit, maximizing the contact surface area. This makes for a
more efficient transfer of energy and reduces arcing which results in
less heat created on the commutator surface as well as less Radio
Frequency Interference (RFI). A broken-in motor can produce 10-30% more
power than one pulled out of the box and put into full service.
** Note ** All procedures mentioned are assuming a bare motor, with
no prop attached or gearbox. Break-in procedures are most effective
under no load! Also, break-in the motor in the intended operational
direction for most effectiveness.
Methods and Variables
Let the debate begin! Each hobbyist has a different method they
swear by for breaking in a DC brushed motor. Manufacturers even have
their own procedures. I would recommend for starters investigating the
manufacturer’s recommended break-in procedures for your specific motor
as any other method may void the warranty. But, if there are no
specific recommendations and you are comfortable going out on your own,
let’s begin with the major factors to consider: Low Temperature - Heat is not required to break in a
motor! In fact, room temperature is just right. Some people even ice
their motors during break-in. Minimal Arcing - Arcing causes pits to form both on
the brush surface as well as the commutator. Arcing also generates
unwanted heat. Break-in recommendations are to supply 1/3 to 1/2 the
normal operating voltage. This greatly reduces arcing. Cleanliness - As the brushes wear against the
commutator, small carbon particles begin to collect and blow around
inside the motor. While this is relatively minimal, the particles do
stick everywhere and also grind between the brushes and commutator.
Some people say this is beneficial to getting a good seat and I’m not
here to debate the point, but my personal preference is to keep the
motor clean during break-in. Voltage - Break-in recommendations typically average
the supply voltage to around 1/3 to 1/2 operating voltage. Again, the
goal is to minimize heat and arcing and allow the brushes to gracefully
seat themselves into the commutator. So, on a 12 volt motor you’d break
it in on 4-6 volts. It’s perfectly ok to start at 2 or 3 volts and
ramp up to a higher voltage over time. Something you will see during
the break-in is the amperage will decrease going to the motor. If
you’re savvy with a multi-meter, or have an amp meter, watch the
amperage decline while the motor is running as the brushes become more
efficient! Time - Most break-in procedures range from 60-120
minutes. Some battery chargers even have a motor break-in feature that
allow you to set the step voltage and time for your motor break-in to
your liking. It will automatically increase the voltage over the course
of the break-in for a gentle ramp through the RPM range. If you
monitor the amperage draw, you will see it “level off” at some point.
Once this is achieved, the break-in is finished and you’re ready to run
your motor at standard operating speeds. If you are using the battery
method and cannot monitor the amperage draw, I would recommend at least
an hour break-in to obtain effective results.
DuraTrax IntelliPeak ICE charger breaking-in a Brushed DC motor
** Note ** Do not directly connect Lithium Polymer or Nickel-Metal
Hydride rechargeable batteries for motor break-in unless you plan to
disconnect them before they reach minimum voltage. Lithium Polymer
(Li-Po/Li-poly) and Nickel-Metal Hydride (NiMH) batteries should not be
discharged below certain levels or they become permanently damaged or
suffer reduced life and performance. See the Batteries section for more
information about proper usage of your rechargeable batteries. If you
plan to use a direct-connected rechargeable source, I keep an old 4 cell
(4.8 volts) Nickel-Cadmium (Ni-Cd) battery around; they have no problem
with being fully discharged.
Wet -vs- Dry
Wet
Wet break-ins involve submerging the motor (not the battery or anything
else) in liquid in order to keep it cool and wash away carbon debris. A
common myth is that the water will cause a short in the motor and even
overheat the battery. Simply not true.
Some people use Distilled Water, Rubbing Alcohol or common tap water.
I would caution the use of tap water due to the fact that minerals in
the water leave deposits all over the inside of your motor. Those same
minerals also greatly increase the conductivity of the water, not that
this is really a problem during break-in, but I’m not keen on leaving
abrasive, conductive minerals all over inside my electric motor.
Rubbing Alcohol does pose some fire risk, albeit minimal, but
evaporates nicely after the break-in is finished. Consider performing
the break-in outdoors and away from structures if you are using rubbing
alcohol. Water break-ins must be cleaned afterwards to avoid corrosion
and rust. I use compressed air through the holes and this works pretty
well. You also will want to lubricate the bushings at the end of the
axle with some very light weight hobby oil or even a couple drops of
3-in-1 or sewing machine oil. GO SPARINGLY. An oily motor collects
dirt and can greatly interfere with your commutator/brush efficiency.
Avoid getting it all over inside the motor and avoid penetrating
lubricants such as WD-40. Just a drop on the bushings from the outside
will do. Don’t disassemble the motor after break-in! The brushes
typically do not seat the same after re-assembly. Dry
Dry break-ins are most common and are very easy. In fact, many people
do their break-ins with alkaline batteries as the power source and a
heat sink snapped over the motor to help keep it cool. They simply let
it run until the batteries are dead. Again, we have almost nothing to
lose here! Even a partially broken-in motor will out-perform a new one.
With dry break-ins, keep the motor in a well ventilated area, away
from heat sources, and you’ll have excellent success. Use the Voltage
recommendations below to properly size your source batteries.
Researchers at NASA’s Jet Propulsion
Laboratory (JPL) and the California Institute of Technology (Caltech),
both in Pasadena, have developed a new type of amplifier for boosting
electrical signals. The device can be used for everything from studying
stars, galaxies and black holes to exploring the quantum world and
developing quantum computers.
“This amplifier will redefine what it is possible to measure,” said
Jonas Zmuidzinas, chief technologist at JPL, who is Caltech’s Merle
Kingsley Professor of Physics and a member of the research team.
An amplifier is a device that increases the strength of a weak
signal. “Amplifiers play a basic role in a wide range of scientific
measurements and in electronics in general,” said Peter Day, a principal
scientist at JPL and a visiting associate in physics at Caltech. “For
many tasks, current amplifiers are good enough. But for the most
demanding applications, the shortcomings of the available technologies
limit us.”
The new amplifier (above) consists of a superconducting material,
niobium titanium nitride, coiled into a double spiral 16 millimeters in
diameter.
Although the amplifier has a host of potential applications, the
reason the researchers built the device was to help them study the
universe. The team built the instrument to boost microwave signals, but
the new design can be used to build amplifiers that help astronomers
observe in a wide range of wavelengths, from radio waves to X-rays.
Greenhouse emissions and Global warming are
not just news stories; they are concerns that are driving change.
Electrical "Green" technologies are gathering momentum for new
development; retrofit solar- electric augmentation, energy smart homes
and commercial buildings. Are you ready?
We at E & S Electric are staying above the curve of the latest
technologies in our industry. We can assist in the designing,
application, installation, analysis, LEED certification, and work with
your local utilities reimbursements process.
"Green" Technology often translates into huge savings especially on
electricity costs, enough to pay for the project over the long-run. Also
it could mean tax breaks. Remember save the Earth and save money too.
We've been researching and implementing "green" for years. Our ongoing
research and training will give our clients the best for this evolving
change "green" has to offer.
Here is a list of the "Green" Retrofit jobs we have completed.
St Vincent DePaul locations in Madison, Waunakee and Stoughton
Mt. Horeb School District
Sun Prairie School District
Belleville School District
Suttle Straus, Waunakee
VFW Post 7591, Madison
Monroe Lumber
Piggly Wiggly Sauk City
St. John Catholic School Waunakee
CL Swanson, Madison
Federal Industries, Belleville
Mt. Horeb Youth Center
Robert W. Baird, Madison
Movie Gallery, Mt. Horeb
Here is a list of completed jobs with energy saving lighting controls:
Iconica, Madison
Madison National Life Insurance, Madison
Wells Fargo, Madison
Tomotherapy, Madison
Associated Bank, Madison
State Bank of Cross Plains, Mt. Horeb
Amcore Bank, Madison
Farmers Saving Bank, Mt. Horeb
First National Bank of Platteville
UW Credit Union locations in Madison, Monona, Glendale, Sun Prairie, Middleton
Holliday Inn, Madison
USDA, Madison
The Gialamas Company, Madison
Kalahari, Lake Delton
Minitube, Mt. Horeb
Mirus, Madison
Hill & Wilson Dental Clinic, Madison
Madison Vein and Laser, Madison
What is LEED?
LEED stands for - Leadership in Energy and Environmental Design.
LEED provides third-party certification for buildings to meet the
highest standards for energy efficiency and environmental
responsibility. LEED provides building owners and operators with the
tools they need to have an immediate and measurable impact on their
buildings. The LEED program is helping the industry; adopt where we
design, locate, build and retrofit buildings to achieve sustainability
in our work and life styles" E & S Electric goal is to be doing
green (vs. going green)with help from loyal customer and our community
to generate sustainable revenue, achieving sustainability now and for
the future for Mother Earth. LEED Accredited professionals are
professionals who understand the green building practices, principles
and a familiarity with LEED requirements, they can help you understand
the LEED process and be the resource for you to move to the
sustainability movement by following guidelines of the USGBC.
THE U.S.GREEN BUILDING COUCIL (USGBC) is a nonprofit composed of
leaders from every sector of the building industry working to promote
building communities that are environmentally responsible, profitable,
and healthy place to live and work.
