Originally Posted by mcvane
We tend to have a lot of brown outs and power interuptions that tend to reset computers and appliances (like clock radios and VCRs) in some rooms in our house.
I have a UPS for my main computer, but I have several, and instead of investing in more UPS'es, I would like to possibly install something on the main circuit panel that is even a 30 second battery backup - it doesn't have to be long...just so that computers don't reboot and VCRs don't reset in the 1/2 second of time when power is cut and reestablished.
Is there such an item out there that is available for consumer purchase?
There is such a device bit it only works if the supply is relatively stable ie supply fluctuations that only last for 1 or 2 cycles (1 cycle equals 16.7 milliseconds). The device is a ferroresonannt transformer aka a constant voltage transformer.
Normally these devices are used to overcome small transients in an otherwise stable supply. A typical application would be protecting sensitive electronic equipment. The problem is that they are expensive & you may not find one big enough to supply your whole house. I guess the biggest economical size would be about 10kVA.
Stick with your UPS units. If they are the "online" type, all the better. A UPS to supply your house would cost a small fortune.
Another alternative is an AVS (Automatic Voltage Stabilizer). They are more suited for extreme supply fluctuations and are priced according to size. At a guess, a typical family household would have a demand not exceeding 20kW. An AVS of this size would also be very expensive.