kikiam,
binili ko magnetic starter in evangelista area in manila, likod ng quiapo church. you could also buy it from electrical supplies.
a magnetic starter is actually used in motor starting. the size of the starter would depend on the number of PCs you have. you need a good industrial electrician to help you in installing it.
when the magnetic starter is activated, all your PCs are connected to it. this means that after your circuit breaker, the contacts of the starter is connected in series supplying your computers.
in my shop, my aircon is also connected to the starter also to protect the aircon.
to give you a better idea, the starter is similar to the power-on-delay (POD) used for aircons and refs. the difference is that PODs reset automatically after several minutes while the magnetic starter could be started manually. your power would be restored once you push the start button. dont use a POD alone coz it won't be enough for all your PCs. kung apat lang PC mo ok na ang POD intended for aircons.
i remember, when i first installed my magnetic starter, i used a POD to reset it. but i decided to remove it coz power restoration (waiting time) is quite long.
an avr won't be of help during fluctuation. UPS dapat talaga yan nga lang mahal kung lalagyan mo lahat ng PC.
if you find an electrician in your area, text mo ko ang i will give him instructions on how to do it. 09175009313 Alex