UPS
An Uninterruptible Power Supply (UPS) is a device that sits between an A/C outlet (i.e. a wall outlet or power strip) and an electronic device (such as a computer, server, or phone equipment) to prevent wide range of power disturbances such as outages, sags, surges, spikes, noise, etc. from affecting the performance and life of the electronic device and vital data.
There are basically three types of UPS: Offline, Line-interactive and On-line.
An Offline UPS provides filtering and protection from spikes and surges, While "standing by" with batteries in the case of a low voltage, high voltage or blackout condition. If one of these conditions occurs, the inverter automatically switches to battery mode to condition the power.
Line-interactive UPS provides automatic regulation to the I/P voltage. It regulates the input voltages and provides O/P voltage within range. Line-interactive UPS fall between an online and offline in terms of cost and performance. In a blackout situation, V-GUARD line-interactive UPS will switch to battery mode in less than 4 milliseconds. Additionally, line-interactive units provide protection from spikes and surges, plus RFI and EMI filtering. V-Guard offline UPS is designed with pseudo sine wave O/P in battery mode.
The on-line UPS provides the highest quality of power protection by incorporating a double-conversion technique, whereby power coming in to the UPS is converted from AC to DC. Power is then conditioned and converted back to AC at the output of the UPS. There is no transfer or switching time since power actually runs through the battery system. By isolating the input from the output, on-line UPS provide true sine-wave power to connected equipment that is clean and free of any power anomalies.
The wattage and VA (volt amp) ratings on a UPS indicate the amount of devices you can safely plug into the unit. They are different ways of measuring the amount of power a device takes. For some appliances, the VA rating and the wattage ratings will be the same (such as an incandescent bulb), however for most computer equipment, the maximum wattage will be less than the VA rating. Each UPS has a VA/wattage rating which is displayed on their listing page.
The following kind of equipment can be connected with a UPS: Personal Computers, LCD Monitors, Printers, Modems, Scanners, Plotters, Cash Registers, Security systems, LCD Projectors, Recording systems, Medical Equipment and more
AVR stands for Automatic Voltage Regulation. A unit equipped with AVR is able to take sagging or high voltage and correct them into an acceptable range without using battery power. Units that are not equipped with AVR will still protect the load in the event of a power sag or spike, but they will simply switch to battery power which may drain the battery causing the UPS to turn off the load once the battery is depleted.
There are three major types of loads: Resistive load (Lamps), SPS load (PC power supply) and Capacitive Load (Motors). All the types of load can be used with Pure Sine wave. However, only Resistive and SPS loads can be used with Modified Sine wave.
Any UPS should be initially charged for 8-10 hours to get the required back-up from the UPS. Avoid UPS installation near to the magnetic field. Ensure the rating of the MCB used at the input of AC outlet and also proper make sure earthing of the system is also appropriate.
You should look at the following parameters before choosing the right kind of UPS:
- Load to be supported by the UPS
- Understand specifications of UPS
- Consider the requirement of power quality
- Understand the current capacity of UPS and consider the future expanding
- Look for a better network of service and sales network
- Choose the UPS based on your requirements
You should look at the following parameters before choosing the right kind of UPS:
- Microcontroller based technology
- Cold start facility
- Performs in a wide input range
- Off mode battery charging with high voltage cut-off
- Battery over charge and deep discharge protection.
- Generator compatibility