what is the difference between a star system and a delta system? (electrical power systems)?
92400
Usually a delt system is compared with a "Y" (wye) system.  A delta is a Greek letter often represented as a three-sided triangle and a Y is a letter with three members (two arms and one leg).  The important feature is threeness.\n\nElectrical power is supplied in three phases (single-phase, two-phase and three-phase) involving voltages of 110, 220 and 440 Volts, respectively.  Single phase is used for light bulbs, two-phase is used for heaters (such as clothes dryers and kitchen ranges) and three phase is used for very large motors.  Alternating current (AC) forms a sinusoid and in three-phase current the sinusoids are out of phase (reaching peak voltages at different times (but 60 times per second each) and this delivers high voltage and maximum power.\n\nThere are two common methods of winding transformers and motors to take advantage of three-phase current and these are referred to as "delta windings" and "Y-windings."  For purposes of circuit analysis they are equivalent.
348003
Have a look at http://science.howstuffworks.com/power.htm
751409
Depending on your sign convention, power can be negative, but it's no longer power being produced, but power being consumed, instead. Or vice versa, again depending on your sign convention (ie in thermodynamics, positive power is power being produced, but in circuits, positive power is power being consumed).
1166968
There are many differences.\n\nBy the wording of your question, it sounds like you are speaking about the movement of celestial bodies.\n\nMost stars (except the sun, seem to stay in the same position in relation to one another.  The sun, moon and   the planets, change their position against the background of the "fixed" stars.  \n\nThis is because the objects in our solar system are close to us, so their change in position is much easier to see.  The fixed stars are so much further away, that their motion is harder to detect.\n\nThis is similar to the experience of riding in a car.  If you look at a distant mountain,  the appearance of it doesn't change very quickly.  But as you come close to a street or a building, the appearance changes dramatically. \n\nThe reason is that if you measure apparent motion by an angle,  an object twice as far from you must move twice the distance across your Field of vision to have the same apparent motion.
23553
Star's are for the most part the same as our star/sun. The difference being we named our star The Sun.
540687
An active satellite is a one that generates power for its own functioning.\n\nA passive satellite needs external power supply for its operation. The external power supply may be provided with solar cells etc.
1068516
Stars are classified by their spectral type and absolute magnitude. The main spectral types run OBAFGKM, in order of decreasing temperature.  The absolute magnitude is the brightness of the star corrected for distance. A plot of these two characteristics for a group of stars is called a Hertzsprung-Russel diagram.\n\nCan't help with the biology stuff, sorry.
412964
use the delta when you are starting a large motor since it can be hooked to energize only part of the windings of the motor at a time this allows for less amperage to be used to get the thing turning
1008829
The similarity is that neither works so far. \n\nThe difference is that if one creates ions of deuterium and tritium which have positive electrical charge one can confine them with a magnetic field in a device called a tokamak and heat them until they are at a temerature where fusion can occur.  The device works, sort of, but requires more energy than it produces.\n\nThe use of lasers to create fusion involves creating pellets of deuterium-tritium and zapping them with a combination of lasers to both compress and heat the pellets to create enough energy to cause fusion to occur.  This can also be theoretically accomplished using ion beams instead of lasers. Both are being experimented with.
1040867
Using 3 phase current, it is possible to get 3 times the energy down the same wire - so it is much more efficient.  Each phase is 120 degrees out from the others, so the signal looks kind of like braided hair, when one phase is at the peak, the other two are crossing at 70%, one going up the other going down.  Once we get the energy to where we want to use it, then we can tap off the different phases for single phase use. \n\nI forget about the delta and wye stuff, it's been a while. \n\nCheers!
189365
u know water flows from higher altitudes to lower.ie, for the flow of fluids a hight difference is needed ,,interms of energy a difference in potential energy is needed.like that for the flow of current a difference in electric energy is needed .this energy difference is called potential difference.\n\n              if we connect an emf source to a resister,the energy difference form btn the terminals of resister
922773
Hydraulic power is not a power source.  There is no energy storage in a hydraulic system.  Power sources like batteries with electric motors or an internal combustion engine with a gas tank are power sources because they can store energy for use at a later time.\n\nThe great thing about hydraulics is the very high power density (lots of power in a small space) and the flexibility in having both linear and rotary actuators.  The main drawback (at least for me working in robotics) is the need for a real-time continuous power input to run the system.
391184
A blue star is hotter than a red star.  Both stars are a color due to how hot they are (just like an electric stove-top).  The main color goes from red to blue as things get hotter.
438982
Electronics - named the Queen of technologies - is a subsidiary of Electrical Science, which focused on low-voltage circuits; while electrical science mainly concentrates on power production, distribution, and loss.
471954
Greetings,\n\nI would imagine they both could be depending on the size, age, and life cycle of the particular star.\n\n-matt
356177
In lay man's terms:\n\nA star: a huge ball of fire, emitting heat and light, mostly composed of gasses and the source of the heat is the nuclear reactions happening isnide it due to the massive pressure in its core. An example is the sun, the temperture of its surface if more than 5000 degress centigrade, while the temperature of its core is several million degrees. A star is 'usualy' much larger than planets(thouthands to millions of times larger) . Some stars have planets orbiting around them (e,g, our sun)\n\nPlanets: Intert masses that do not emit light or radiate heat. Planets revolve around stars and are far much smaller than stars(e.g. earth, mars, saturn, jupiter,etc). Some planets have moons(much smaller planets) revolving around them.Mostly planets are solid masses, but sometimes they are made of gases. The temperature of planets is far cooler than stars.
752296
With a bus topology, all devices are connected to a single backbone.  In a star topology, all devices are connected to a single hub.