f = PN/120 where f is frequency of power supply, P is number of poles in the machine and N = speed in rpm. So, Synchronous speed N = 120f/P. Thus for 50 Hz supply, 2 pole machine; synchronous speed = 3000rpm. ETRICAL
Within our solar system quite a bit of exploration has been done by spacecraft including orbiters and landers. Planets outside our solar system will be difficult or impossible to explore with spacecraft in our lifetimes, so astronomers and astrobiologists use other techniques to search for signs of life on these planets. In particular, astronomers are interested in planets within the habitable zone of stars.
The Solar System is located in the Milky Way, a barred spiral galaxy with a diameter of about 100,000 light-years containing about 200 billion stars. The Sun resides in one of the Milky Way's outer spiral arms, known as the OrionâCygnus Arm or Local Spur.f those objects that orbit the Sun directly, the largest eight are the planets, with the remainder being significantly smaller objects, such as dwarf planets and small Solar System bodies such as comets and asteroids. Of those that orbit the Sun indirectly, two are larger than the smallest planet.