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.
LOS ANGELES (AP) â Astronomers searching for planets outside our solar system have discovered the tiniest one yet â one that's about the size of our moon. But hunters for life in the universe will need to poke elsewhere. The new world orbits too close to its sun-like star and is too sizzling to support life.