Static Transfer Switch

how the static transfer switch functions and how it transfers the load without interruption ?

Frequency

how the transformer size will decrease when the operating frequency is increased ? and what are the factors effect the size of transformer when frequency increased ? ,when frequency increase what changes will occur related to size in an alternator and ac motor ?

Ngr

we are having 16 MVA 33/11 kv power transformer . delta/ star connection. the neutral from secondary is grounded through a NGR of 15.88 ohm , 400 amps. we are having different kilowatt rating motors. my doubt is for a 75 kw rating motor what should the earth conductor size (body earth ) and on what bassis the earth conductor size will decide.............

Ring Main Unit

what is ring main unit ? ia there any difference between switchgear and rmu

Speed Above 3000 Rpm

If motor is designed for 2880 rpm. at 415 volts 50 hertz supply.... and it is running with vfd. vfd max freaquency is 400 hertz. can we run the motor above 2880 rpm? if it is possible what are the corresponding changes in voltage and current? is it safe to run the motor beyond the rated rpm in load condition? the motor rating is 75 kw..