The Pelton turbine is an impulse turbine that extracts energy from the impulse of moving water and is the preferred turbine for hydro-power.
Sunday, 24 June 2012
Sunday, 17 June 2012
With a big 5" (12.7 cm) touchscreen, more than 5 million points of interest (POIs) and spoken turn-by-turn directions, nüvi 50LM makes driving fun again. Plus, with FREE lifetime map updates, you always can keep your roads and POIs up to date.
Get Turn-by-turn Directions
nüvi 50LM’s intuitive interface greets you with 2 simple choices: “Where To?” and “View Map.” Touch the screen to easily look up addresses and services and to be guided to your destination with voice-prompted, turn-by-turn directions that speak street names. nüvi 50LM’s speed limit indicator shows you how fast you can go on most major roads. With its “Where Am I?” emergency locator, you always know your location. It also comes preloaded with millions of POIs and offers the ability to add your own.
Enjoy FREE Lifetime Map Updates
With FREE lifetime map¹ updates, you always have the most up-to-date maps, POIs and navigation information available at your fingertips. Map updates are available for download up to 4 times a year with no subscription or update fees and no expiration dates.
Know the Lane Before It’s Too Late
Now there’s no more guessing which lane you need to be in to make an upcoming turn. Available in select metropolitan areas, lane assist with junction view guides you to the correct lane for an approaching turn or exit, making unfamiliar intersections and exits easy to navigate. It realistically displays road signs and junctions on your route along with arrows that indicate the proper lane for navigation.
¹ FREE lifetime map updates entitle you to receive up to 4 map data updates per year, when and as such updates are made available on the Garmin website, for this specific Garmin product only until this product’s useful life expires or Garmin no longer receives map data from its third party supplier, whichever is shorter. The updates you receive will be updates to the same geographic map data originally included with your Garmin product when originally purchased. Garmin may terminate your lifetime map updates at any time if you violate any of the terms of the End User License Agreement accompanying your nüvi product.
Features
Stay up-to-date on changing roads and POIs with FREE lifetime maps.
View routes on the big 5" (12.7 cm) touchscreen.
Look up addresses for over 5 million points of interest.
Hear spoken street names.
Know the lane before it’s too late with lane assist with junction view.
Keep out of trouble with the built-in speed limit indicator.
Friday, 15 June 2012
In electricity supply systems, an earthing system defines the electrical potential of the conductors relative to the Earth's conductive surface. The choice of earthing system can affect the safety and electromagnetic compatibility of the power supply, and regulations can vary considerably among countries. Most electrical systems connect one supply conductor to earth (ground). If a fault within an electrical device connects a "hot" (unearthed) supply conductor to an exposed conductive surface, anyone touching it while electrically connected to the earth (e.g., by standing on it, or touching an earthed sink) will complete a circuit back to the earthed supply conductor and receive an electric shock.
A protective earth, known as an equipment grounding conductor in the US National Electrical Code, avoids this hazard by keeping the exposed conductive surfaces of a device at earth potential. To avoid possible voltage drop no current is allowed to flow in this conductor under normal circumstances, but fault currents will usually trip or blow the fuse or circuit breaker protecting the circuit. A high impedance line-to-ground fault insufficient to trip the overcurrent protection may still trip a residual-current device (ground fault circuit interrupter or GFCI in North America) if one is present.
In contrast, a functional earth connection serves a purpose other than shock protection, and may normally carry current. Examples of devices that use functional earth connections include surge suppressors and electromagnetic interference filters, certain antennas and measurement instruments. But the most important example of a functional earth is the neutral in an electrical supply system. It is a current-carrying conductor connected to earth, often but not always at only one point to avoid earth currents.
The NEC calls it a groundED supply conductor to distinguish it from the equipment groundING conductor. In most developed countries, 220/230/240V sockets with earthed contacts were introduced either just before or soon after WW2, though with considerable national variation in popularity. Until the mid 1990s, US 110V power outlets generally lacked protective earth terminals. In much of the developing world, the situation is stil unclear, and earthed outlets may or may not be provided, and where they are these may not always be reliably connected.
In the absence of a supply earth, devices needing an earth connection often used the supply neutral. Some used dedicated ground rods. Many 110V appliances have polarized plugs to maintain a distinction between "live" and "neutral", but using the supply neutral for equipment earthing can be highly problematical. "Live" and "neutral" might be accidentally reversed in the outlet or plug, or the neutral-to-earth connection might fail or be improperly installed. Even normal load currents in the neutral might generate hazardous voltage drops. For these reasons, most countries have now mandated dedicated protective earth connections that are now almost universal.
source: Wikipedia
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