Power Conditioners vs. UPS
If you live in an area where the electrical power suffers surges frequently, then you may be helped by the use of a power conditioner. What you want to find out about the conditioner is if it is just a series of high priced inductors, filters and surge protectors or if it is of a design that actually does double conversion with completely regulated and shaped output.
Most of the high priced power conditioners are marketing marvels, but do little to actually provide clean power as they claim. If you get down to the exact claims, you will find they cover a pretty narrow spectrum of the power issues one might expect to encounter. One thing that they are intended to suppress is harmonics that are superimposed on the power line that may “leak” into the audio or video. Truth is some brands will do a good job with the upper (higher frequency) harmonics and a poor job with the lower harmonics. The problem is while it looks good on a graph, in practice the lower frequencies will have a greater effect on equipment than the high frequencies as most power supplies in equipment will not pass the high frequencies through their transformers, but will pass the lower frequencies.
There are some power conditioners that use what is called double conversion in where the AC line is converted to regulated DC and then the output is another conversion back to AC. What you end up with is a completely regulated and shaped sine wave output that is isolated from the line power. This type of power conditioner is recommended over the surge protectors. For a discussion comparing these two types of power conditioners see:
Taking this double conversion one step father adding a battery in the DC power stage will allow for momentary power outages to prevent satellite receiver reboot or the shock to high powered lamps in DLP, LCD and LCOS type displays. Here we are talking about a Uninterruptible Power Supply or UPS.
Now bear in mind there are three types of UPS units and depending on the use and the degree of protection you desire, will determine the type you will want to consider. The three type are Standby, Online and Line Interactive.
Standby UPS (Offline)
The AC line is the primary power source. The battery/inverter circuitry supplies the load in case of a power failure for fluctuation. Any drop in the voltage or current is detected by the UPS, which automatically switches the battery into the circuit, cutting of the main power line-thus allowing the battery to supply the required power. The transfer time should not take more than 4 milliseconds, as this is the tolerance limit of a typical computer power unit.
This UPS operates with the inverter as the primary power source supplying the load and therefore there is no transfer time in case of power failure. This type of ‘on-line’ power eliminates any interruptions in the flow of electricity. And since it uses more electronic wizardry than offline UPS, it is priced higher. Besides the high price, on-line UPS also have the disadvantage of high running costs and temperature. Since the battery acts as the primary power source to the system, an on-line UPS battery charger has to be powerful enough to generate enough power to compensate for the batteryâ€™s power drain. This conversion from AC mains to DC for the battery and back to AC through the inverter results in a 25-to 30-percent power loss. The heat generated as a consequence of the power loss shortens the life of electrical components and reduces battery life.
The AC line power is the primary source and is being constantly filtered. In case of a brownout condition the automatic voltage regulation circuitry is activated to correct the problem. The battery and inverter circuitry supplies the backup power in case of a blackout.
Now in my mind the Online will give you the ultimate in power protection and conditioning for your system and if you live in an area where you have particularly dirty power, this would be a good solution. It is also the most expensive. A good second choice is the Line-Interactive UPS where the inverter output tracks the line voltage and is ready to provide a seamless switch to UPS power when trouble arises. The main advantage of this type UPS is the reduced current required by the inverter circuitry, thus increasing its life expectancy. It has been my experience that this is the best overall UPS for home theater use. The Offline UPS because of the switching time will cause a very short power outage of typically 4ms which is normally not going to cause the connected devices any problems, but in my mind it would be better to spend a bit more money and eliminate the power loss altogether.
A couple of other benefits of using a UPS is the ability to power down high powered lamps with the cool down fan still running. This assumes you are watching the TV when the power is lost and you turn the TV off manually. Additionally satellite receivers can be connected to the UPS to avoid lengthy reboot times. Finally I connect my VCR (yes I still have one of those) to keep the time settings during short power outages.
Avr 750VA US120V Line-int 8 OUTLET 5-15R Tel USB 750 Va
A 750VA (approx 600 watts) will handle most LCD, DLP and LCOS displays with enough power to spare to connect a satellite receiver and VCR.
Tripp Lite Omni Vs OMNIVSINT1000 - US( External ) - Ac 230 V - 1000 Va - Ups B
For a bit more power this 1000VA (800 watts) will offer a bit better surge protection and longer backup time.
OPTI-UPS E-Series 1400 - UPS ( external ) - AC 120 V - 1400 VA - 4 output connector(s)
For even more power this 1400VA(1120 watts) for complete system backup.