More Info On Power Protection.

• What is the Difference Between VA and Watts?
• What is a Smart UPS?
• Why Do I Need UPS Monitoring and Automatic Shutdown Software?
• Can UPS Software from One UPS Manufacturer Be Used With a Different Brand of UPS?
• How Do I Calculate Battery Runtime?
• Is There Any Equipment I Should Not Connect to My UPS?
• What is "Switching Time"?
• What is "Buck and Boost"?

What is the Difference Between "VA" and "Watts"?

UPSs are traditionally rated by their power output capability measured in VA, which stands for volt-amps, or volts x amps. Watts is a measure of power consumption and for UPSs is commonly used to indicate the UPS's load capacity, which is the total number of watts above which the UPS would be overloaded. Watts ratings are lower than VA rating. The relationship of watts to VA is by a "power factor" typically ranging from 0.6 - 0.7, or 60 - 70%.

What is a "Smart" UPS?

The real meaning of a "smart" UPS is one which has a built-in microprocessor and an RS-232 interface port. Many people mistakenly believe that in order to have an automatic shutdown capability, a UPS must be "smart". In fact, a UPS with a contact closure serial interface port can normally do an automatic shutdown. A "smart" UPS adds the additional functionality of being able to monitor more operating parameters, for example temperature, humidity, voltage level, etc.

Why Do I Need UPS Monitoring and Automatic Shutdown Software?

During a power interruption, a decision must be made when and if to gracefully shutdown the computer system. On a computer system that always has someone within earshot and eyeshot, this is usually done manually - when the UPS kicks on during a power failure, the administrator decides whether to ride it out on battery power or to save files and close programs. However, on an under-attended or unattended computer system, nobody is around to make that decision. In that case, during a power failure, the UPS will kick on and run the computer system, but only until its battery is depleted. Therefore, it is important to have an automatic shutdown software that will gracefully shut down the computer system after a pre-configured time period of when the computer receives a low battery signal from the UPS. UPS monitoring and automatic shutdown software also can broadcast power fail messages to network workstations, keep an historical log of abnormal power conditions, and alert the system to page the administrator.

Can UPS Software from One UPS Manufacturer Be Used With a Different Brand of UPS?

Generally not. Different software programs have different ways of communicating, use different cable topologies, and different brands of UPSs have different pin assignments on the serial interface port on the UPS.

How Do I Calculate Battery Runtime?

Runtime is the amount of time your UPS can run on battery power before it turns itself off automatically to protect itself against total battery depletion. Runtime is difficult to determine with precision because it depends on many factors, including the actual power consumption, as opposed to the rated power consumption, of the computer or other electronic equipment you are using. Other determinants of runtime include battery type, battery age, UPS design, and various other operating and environmental factors such as temperature. The best way to estimate battery runtime is to gather information about the rated power consumption of all the equipment you will connect to the UPS, and then ask the UPS manufacturer what approximate runtime you can expect to achieve.

Is There Any Equipment I Should Not Connect to My UPS?

In general, you should never connect a laser printer to your UPS because a laser printer draws a tremendous amount of power and will likely overload your UPS and cause the UPS fuse to blow. Most other office equipment, such as computers, monitors, fax machines, and networking equipment, should work fine with most UPSs. Do bear in mind that larger size monitors consume much more power than smaller monitors and will likely reduce battery runtime significantly.

What Is Switching Time?

Switching time refers to the time it takes an offline, or stand-by, type UPS to switch from AC operation to inverter operation when a power interruption occurs. Technically speaking, switching time includes the time it takes for the UPS to sense the power interruption and the time it takes for the UPS to switch over to inverter operation. Generally, most reputable brands of UPSs switch in 2 to 10 milliseconds, depending on the way the interruption is introduced, which is well within the time that the computer's internal switching power supply still outputs some power. For critical applications where you absolutely don't want to take any chances, or if you have some lingering doubts about switching time, but you don't want to spend significantly more money for an online type UPS, you can consider purchasing a product called Glitch Master that is an inexpensive add-on product for your internal switching power supply.

What is Buck and Boost?

Buck and boost are terms used in reference to certain types of voltage regulation. A UPS with built-in voltage regulation capabilities provides correction of high and low voltage conditions. Buck lowers a high voltage and boost raises a low voltage.