A standby ups is thought of the cheapest power conditioner and battery backup for computer equipment.
Generally AC power comes in, charges the batteries, and provides AC output. Take note of the location of the switch. If incoming power is lost, power is "switched" between input AC and your batteries. There is a 2-5ms transfer time when the UPS actually switches to batteries. Note with critical loads, this means loss of data, hard drive lockup, or in the medical industry, instrument failure. Typically this type of UPS is best suited in the home use, where equipment costs are at a minimum. However, a standby uninterruptible power system can be bought for as low as $50.00.
Often times the UPS is accompanied by some sort of equipment warranty, claiming if it damages any of your equipment, they will pay for it. Do not fall for this trap, because it will never happen. There is no way for you to prove that it was actually their UPSs fault.
Advantages:
Stand-by uninterruptible power systems are very inexpensive.
You will get some battery backup during a power outage, if your equipment does not lock up.
Disadvantages:
Very unreliable. Sometimes they will not even switch to batteries
No output voltage regulation. Whatever voltage comes in, goes right to your equipment
No static bypass. If anything goes wrong with this UPS internally, it will automatically turn off.
Very poor filtering (if any). Units will not protect against most surges
No frequency regulation. Now, more then ever, while utility companies are deregulating, frequency is now becoming a growing issue.
Because the unit has to transfer to batteries via a switch, this can cause problems with your equipment
Because of the cheap charging methods, dont be surprised if you are not replacing your batteries every year
About the Author:
Damion McHenry is a power consultant that has worked in the power industry for many years. He worked for a major manufacturer of uninterruptible power supplies in marketing/sales/technical support.
View more information about UPS systems at http://theupspeople.com