Tuesday, September 27, 2011

How Wind Turbines Work!!!

Wind ENERGY
How Wind Turbines Work!!!

-Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetation. Humans use this wind flow, or motion energy, for many purposes: sailing, flying a kite, and even generating electricity.

-The terms wind energy or wind power describes the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity.

-So how do wind turbines make electricity? Simply stated, a wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. Take a look inside a wind turbine to see the various parts in the following figure.

-This aerial view of a wind power plant shows how a group of wind turbines can make electricity for the utility grid. The electricity is sent through transmission and distribution lines to homes, businesses, schools, and so on.



Types of Wind Turbines
-Modern wind turbines fall into two basic groups: the horizontal-axis variety and the vertical-axis design, like the eggbeater-style Darrieus model, named after its French inventor.

-Horizontal-axis wind turbines typically either have two or three blades. These three-bladed wind turbines are operated "upwind," with the blades facing into the wind.


-Utility-scale turbines range in size from 100 kilowatts to as large as several megawatts. Larger turbines are grouped together into wind farms, which provide bulk power to the electrical grid.

-Single small turbines, below 100 kilowatts, are used for homes, telecommunications dishes, or water pumping. Small turbines are sometimes used in connection with diesel generators, batteries, and photovoltaic systems. These systems are called hybrid wind systems and are typically used in remote, off-grid locations, where a connection to the utility grid is not available.

Inside the Wind Turbine

 Turbine Technical Drawing Enlarged
Anemometer:
Measures the wind speed and transmits wind speed data to the controller.
Blades:
Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate.
Brake:
A disc brake, which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies.
Controller:
The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 55 mph. Turbines do not operate at wind speeds above about 55 mph because they might be damaged by the high winds.
Gear box:
Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1000 to 1800 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes.
Generator:
Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.
High-speed shaft:
Drives the generator.
Low-speed shaft:
The rotor turns the low-speed shaft at about 30 to 60 rotations per minute.
Nacelle:
The nacelle sits atop the tower and contains the gear box, low- and high-speed shafts, generator, controller, and brake. Some nacelles are large enough for a helicopter to land on.
Pitch:
Blades are turned, or pitched, out of the wind to control the rotor speed and keep the rotor from turning in winds that are too high or too low to produce electricity.
Rotor:
The blades and the hub together are called the rotor.
Tower:
Towers are made from tubular steel (shown here), concrete, or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.
Wind direction:
This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind," facing away from the wind.
Wind vane:
Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.
Yaw drive:
Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind.
Yaw motor:
Powers the yaw drive.



This Info are from http://www1.eere.energy.gov

Thursday, September 22, 2011

Diesel Generator sizing - How to Determine What Size You Need??

Diesel Generator sizing - How to Determine What Size You Need??

-Getting a generator that can handle all your power generation needs is one of the most critical aspects of the purchasing decision.  Whether you are interested in prime or standby power, if your new generator can't meet your specific requirements then it simply won't be doing anyone any good because it can put undue stress on the unit and even damage some of the devices connected to it.  Unfortunately, determining exactly what size of generator to get is often very difficult and involves a number of factors and considerations.
-Making a choice amongst single phase, three phase, kW, KVA, welder, standby or motor starting generators can be mind-boggling. To prevent such confusion, this article was developed to help you get a better idea of how the sizing process works and some key things to keep in mind.

Generator Size Variations
-With the latest advancements in the field of electrical engineering, generators are now available in a wide range of sizes. Generators with power supply capacities of 5kW to 50kW are readily available in the personal and home use markets, while industrial generators are anywhere from 50kW to over 3 Megawatts.  Handy and portable gen sets are available for homes, RV's and small offices, but larger businesses, data centers, buildings, plants, and industrial applications need to use the much larger sized industrial generators to meet their higher power requirements.

Generator Sizing - How Much Power
-Many people believe smaller generators can be used for standby electric power because they are not running all the time. This is not only a myth but can actually be very detrimental. Unfortunately, generator under sizing is one of the most common mistakes committed by buyers.  Not only does it involve the risks of damaging your new asset (the generator), but it can also damage other assets connected to it, create hazardous situations, and even limit overall productivity of the unit and/or the business relying on it.  If nothing else, the key thing to remember here is that more is always better than less.

Know Your Requirements

Going to a dealer and buying the best or cheapest generator available without any other consideration is clearly not the best approach. It is always better to delve deep into your power generation requirements before making a choice. You can do this in the following ways:

- Make a list of the items that need to be powered by the generator
- Make a note of the starting and running wattage of the respective items
- Calculate the total power requirements in KVA or KW

Advantages of choosing the right size generator
Now that you have an idea on how to choose the appropriate size of generator to suit your needs, here's just a few of the benefits obtained by going through that process:

- No unexpected system failures
- No shutdowns due to capacity overload
- Increased longevity of the generator
- Guaranteed performance
- Smoother hassle-free maintenance
- Increased system life span
- Assured personal safety
- Much smaller chance of asset damage

Tuesday, September 20, 2011

Ingress Protection Codes and Classification IP CODE

Ingress Protection Codes and Classification IP CODE

- The IPCODE (IP code) is used to stipulate the environmental protection applicable for specific equipment enclosures.
-When we purchase any electrical equipment, mechanical devices, household instruments, or enclosures, it is important to identify what degree of IP rating or IP Code (Ingress Protection) the equipment offers. Ingress of solid or liquid particles into the equipment can be dangerous to humans as well as machinery.
-The intention of this rating is to provide consumers and end users clearer details than advertising terminology such as "rainproof" or "waterproof."
-The IP code is used to stipulate the environmental protection used for specific equipment enclosure.
**Normally an IP code has two numbers:
  • Protection from solid particles
  • Protection from liquids
As an example, with the rating "IP 23," the first digit "2" describes the level of protection from solid objects and second digit "3" describes the level of protection from liquids.
  • 2 = Protected against solid objects up to 12mm, e.g. fingers.
  • 3 = Protected against direct sprays of water up to 60° from the vertical.

IP Standards

An engineer working within industry should understand the types of enclosures provided against hazardous parts and the ingress of solid foreign particles for all equipment located in the plant. Also during design of machines, an engineer should take care of IP codes of equipment, considering its application and the surrounding condition of placement.
The applicable European standards for ingress protection are:
  • BS EN 60529 Specification of Degrees of Protection Provided by Enclosures
  • IEC 529 Specification of Degrees of Protection Provided by Enclosures
Both of these provide a numerical code to classify the degree of protection offered. Please click on the following link to view the table.





This information source from ‘’ ContractorsUnlimited.co.uk ‘’.

Monday, September 19, 2011

OPERATION JOB OR TECHNICAL PLANNING ??

HELLO EVERYONE

I want to share with you an important question , and I hope you have a reply for me ?
What would you choose if there are two offers for work and why ?

The first Offer , is to work as an operational Engineer at Electricity Power Generation Utility and you have to make the proper control and optimization for the whole unit.

The seconde Offer , is to work at Technical Planning Engineer for a company in telecommunication Sector , and you have to make proper tenders and recommendation for purchasing and order of Electrical Equipments like Diesel Units , Batteries , Medium Voltage Panels , UPS , INVERTERS , Rectifirers.


I want your replies so soon , please , and thanks for your interest.

Khaled Hamza