UPS Inverter

While choosing the right inverter or UPS might seem a little complicated at first, it really isn’t. To begin with, you just need to answer the following questions: What are the different types of appliances you need to run? Are they sensitive to electrical fluctuations? Such sensitive appliances may include your computer or that expensive TV.

If yes, then it is highly recommended that you purchase a Sine wave inverter/home UPS with minimal transfer time (explained below). If not, then normal appliances such as regular fans or tube lights run just fine with regular inverter/home UPS systems which are much cheaper than comparable sine wave ones.

Yes, if you have bought a square wave inverter/UPS. A humming sound with such inverter/UPS systems is normal.

Nothing in particular. All you need to be careful of is the type of equipment and appliances you want to run. For sensitive ones, a Sine Wave UPS with a short transfer time is recommended. If you wish to run only fans and tube lights, a square wave inverter/home UPS will suffice. The backup time will depend on the capacity of the battery.

There could be two main reasons for this:

1. Your battery needs to be either charged or replaced. 2. You are trying to run the wrong appliances:

However, for other electrical appliances such as an air conditioner, your existing inverter or UPS might not be enough. This is because some of these appliances need a lot of power to start (sometimes as much as 300% of their operational power). In this case, even if your inverter/UPS is rated above the power rating of a heavy appliance, it might not be able to run it, simply due to the high start-up power required.

Your battery does not have enough charge to power your fans and lights. Please re-charge and re-check the water level of your battery. If that doesn’t solve the problem, change the battery (in case dimming is a persistent problem even after proper charging and refilling the battery). Also, ensure that you are not overloading the inverter/UPS as even this might cause some appliances to run below their actual capacity.

No. Automotive batteries are only suitable for cars since they are used to provide power for a short duration. Hooking up these batteries to an inverter or UPS might damage the battery and the inverter/UPS in addition to voiding the warranty.

The power drawn by computing equipment is expressed in Watts or Volt-Amps (VA). The power in Watts is the real power drawn by the equipment. Volt-Amps are called the “apparent power�? and are the product of the voltage applied to the equipment times the current drawn by the equipment. Both Watt and VA ratings have a use and purpose. The Watt rating determines the actual power purchased from the utility company and the heat loading generated by the equipment. The VA rating is used for sizing wiring and circuit breakers. The VA and Watt ratings for some types of electrical loads, like incandescent light bulbs, are identical. However, for computer equipment the Watt and VA ratings can differ significantly, with the VA rating always being equal to or larger than the Watt rating.

Yes, you can add a separate line interactive UPS for your desktop even if you already have an inverter/home UPS. Your existing inverter/home UPS may take as much as 2-3 seconds to power on. This is enough to switch off your computer randomly. Not only do you stand to lose important data, there is also a risk that the computer might get damaged. A small line interactive UPS (about 600 VA) will allow you to continue working without any problems whatsoever.

A pure sine wave inverter/home UPS with a short transfer time is recommended for sensitive equipment. Sensitive equipment requires a stable power source that only such systems can provide during a power cut. Even in the absence of a power cut, these systems can stabilize the fluctuations in electricity, thereby protecting your equipment from damage.

The power supply that you get from the local electricity board looks something like this: All your appliances are built according to this smooth, ‘sine wave’.

However, when the power goes off, a UPS or an Inverter, depending on its technology can produce any of the following waves to give you back up power:

Square Wave:
This is the electricity output from an inverter/UPS that produces a square wave. Clearly, this does not look like the actual smooth wave that comes from the mains. This is one of the reasons why sensitive appliances are not recommended for square wave inverters and UPS systems. Since these systems are cheaper, running basic appliances such as fans and tube lights on these systems is not a problem. However, a square wave can produce a humming sound from fans and tube lights. If this is not an issue, a square wave inverter is perfect for those who want to run basic appliances such as fans and lights.

Modified Sine Wave
These systems are somewhere in between a square wave inverter/UPS and a pure sine wave one. Modified sine wave inverter and UPS systems produce an output that crudely resembles a sine wave. In other words, the output is a lot better than square wave systems. What this does is that it eliminates the humming sound associated with square wave inverters/UPS systems. Even though the output is better than a square wave inverter, running sensitive equipment such as computers is still not recommended.

Pure Sine wave
The output from a pure sine wave inverter /UPS looks exactly like that received from the mains. These systems can be used to run anything from a computer to a television, provided, of course, that the capacity is enough to run such appliances. Since there is hardly any difference between power received from the mains and the power produced by these systems, the cost is accordingly higher.

Transfer time is simply the time taken by an inverter/home UPS to switch on when electricity (from the mains supply) goes off. The transfer time can range from as high as 500 milli seconds (ms) to as low as 10 ms. The lower the transfer time, the better. With a short switch over time, appliances do not need to restart. However, if transfer time is on the higher side, appliances will switch off when the mains power goes off and then switch back on when the inverter/home UPS powers on.

If you have LED TVs, computers or any other sensitive equipment at your home or office, the use of a sine wave inverter/home UPS with a short transfer time is highly recommended. This is because the appliances do not switch off when the mains power goes off and the risk of damage to the equipment is minimized.

Online UPS: These systems are usually employed in places such as banks, IT firms, hospitals etc. where power outages cannot be tolerated. All of these places have highly sensitive equipment and online UPS is the perfect tool for these places. Not only does an online UPS provide clean power by stabilizing fluctuations, the switch to back up power from a battery is instantaneous. What this means is that every appliance running on an online UPS is protected from damage regardless of a poor input source or lack of power.

Advantages
--Stabilizes voltage fluctuations --Instantaneous switchover to battery power in case of a power cut --Ideal for places that keep sensitive equipment --Can be used to run any and every appliance without a problem

Disadvantages
--Expensive --Bigger units require a large number of batteries and therefore a lot of storage space.

Line Interactive or computer UPS: Like an online UPS, a line interactive UPS also regulates voltage to certain extent. However, its switchover time to battery power isn’t instantaneous and it is therefore not recommended for super sensitive equipment such as servers and hospital equipment.

Advantages --Stabilizes voltage fluctuations to a certain extent --Cost effective --Usually small in size. Can be stored or hidden anywhere.

Disadvantages
--The switchover time isn’t instantaneous as in the case of an online UPS --Usually comes with an in-built battery that provides back up for only a short time.