Question { UltraTech, 6497 }

i want to know is it possible to generate usefull power by
coupling generator with motor & supply gives to motor by
battery source then generator generates power. remove the
battery source given to the motor & feed the supply from
some of the generated power supply to the motor & motor
runs continously. generator generate power contnously.is it
possible ?

Answer

It is not possible.........to do so either motor or
alternator efficiency should be more than 100% which is not
possible.....
Ex.. let motor i/p power= P1
o/p power= p2
generator i/p power= q1
o/p power= q2
here p2 cannot be more than p1 ,lly q2 cannot be more than
q1 because of copper,friction and windage losses......so
obviously q2 lesser than p1....so motor cannot run

Note: Energy neither be created nor destroyed...only it can
be transferred from one form 2 other....

Question { 8214 }

Megger type of instrument is used to check??

Answer

generally under ground cables have very high insulation
resistance in the range of mega ohms.........to measure such
high insulation resistance we use Megger instrument...........