I have an inverter, then a UPS, as the inverter does not always keep the PC on. The inverter does not power the UPS so it cuts out after a few mins, I then have to take the UPS out of the system until the power comes back on?

We all use many devices and equipments that run on electricity. For all these to function properly they need uniform power supply (constant flow of electricity). As the electric supply in many countries is not uniform there is a need for a device to correct it. There are many such devices available in the market today. For example UPS (Uninterrupted power supply), Voltage Stabilizer, Constant Voltage Transformer are such devices available today.<br /> <br /> <b><u>Why buy a UPS?</u></b><br />We can never guarantee that we will get constant power. The power supply always has fluctuations. Surges, Spikes, Brownouts, Blackouts and Noise can damage your electrical appliances especially your computer. To prevent this from happening you need a device that does power conditioning. Electricity has to be uninterrupted. If the voltage is higher than the specified level then it is 'Over Voltage'. If the voltage is lower than the specified level then it is 'Under Voltage'. Both Spike and Surge come under 'Over Voltage' category. But there is a small difference between spike and surge. If there is very high voltage for an instant but comes back to normal immediately then it is called 'Spike'. If there is very high voltage for a slightly longer period then it is called 'Surge'. If the voltage is dangerously reduced to very low within a short period of time then it is called 'Brownout'. When this happens, the computer can be seriously damaged. If the power supply is totally cut then it is called 'Blackout'. Noise can mix with electromagnetic or radio waves or any signals. This is called 'Line Noise'. This may also reduce the voltage level to very low within a short period of time.<br /> <br /> <b><u>How can the UPS provide power when the main electrical supply is cut?<br /></u></b>A UPS has an internal battery. With this battery charger, an Inverter is also present. The inverter converts the 'Direct current' supplied by the battery to 'Alternatinc current' as required by the computer. When there is electrical supply the charger in the UPS charges the internal battery. When there is a power cut, the battery kicks in to supply the DC which is converted to AC by the inverter and power is supplied to computer.<br /> <b></b> <br /> <b><u>What if the battery loses its power?</u></b><br />When there is power cut, the required power is taken from the battery. Therefore the battery keeps losing its capacity. If the power supply comes back before the battery is depleted then the battery charger will start recharging, but if the power supply doesn't come back then the battery keeps supplying until it totally drains out. When the battery drains below a certain level the UPS sounds an alarm for your to shut down your computer and turn off the UPS. Some UPS' even have a built in system that shuts your computer down for you after a certain amount of UPS uptime.<br /> <b></b> <br /> <b><u>How long can the UPS provide power when there is a blackout?</u></b><br />This all depends on the specifications of the UPS and the requirement of the computer. A 600vA UPS for example can supply power to a computer with a 550W power supply for about 10 minutes or more.<br /> <b></b> <br /> <b><u>Tips for buying an UPS</u></b><br />The backup time of your UPS is the most important you need to consider. Other than that, you should know how many KVA (Kilo Volt Ampere) your UPS has. A computer needs atleast 0.5 KVA (500VA) to function. If you are planning to connect more than one computer to a single UPS then you need to get one with a higher KVA.<br /> <b></b> <br /> <b><u>What type of battery does a UPS use?</u></b><br />UPS uses <b>SMF</b> batteries (Sealed Maintenance Free). These type of batteries can be used for 5 to 7 years continuously.