FAQ's on UPS

Wave Design Systems believes a greener future is a must for our children and thus sustains it's effort to make the world pollution free. Wave Design systems designs and manufactures UPS from 100VA to 3000VA for varied applications for homes and small offices.  These UPS systems are powered by Solar Energy to charge the battery banks using the Sophisticated WPTO Charger system which can charge the battery banks even during cold, foggy cloudy conditions.  Please read the WPTO Controller FAQ for more information.


An FAQ is presented for people who are new to UPS and inverter technology and as well as for many who use UPS at homes but would like to know more.

Q: Glossary: Terms used in the FAQ

Blackout

Complete loss of power. Some literature considers a voltage drop below about 80V to be a blackout as well since most equipment will not operate below these levels.

Sag or Brownout

Decrease in voltage levels which can last for periods ranging from fractions of a second to hours. Can be caused by heavy equipment coming on line such as shop tools, elevators, compressors etc. Also occurs when utility companies deliberately do this to cope with peak load times.

Spike

An tremendous increase in voltage over a very short period of time often caused by a direct lightning strike on a power line or when power returns after a blackout.

Surge

An substantial increase in voltage lasting a small fraction of a second, often caused when high powered appliances such as air conditioners are switched off.

EMI/RFI Noise

ElectroMagnetic Interference and Radio Frequency Interference. Caused by, inter alia, lightning, generators, radio transmitters, industrial equipment.

MOV

Metal Oxide Varistors are added to circuits in order to control spikes. These are common in Power Strips. If you see more than two, you likely have a fairly decent Power Strip. They look like largish disk capacitors.

Inverter

Circuitry that converts DC battery power to AC power required by most computer equipment.

Surge Protector

Circuitry consisting of MOVs, capacitors, rod-core inductors etc. for suppressing surges and spikes usually embedded in a power strip.

Line Conditioner

A transformer that attempts to smooth out fluctuations in input voltage to provide near uniform output voltage or voltage waveform. 

TOPIC: What is a UPS and how does is work

Q: What is a UPS?
A: An Uninterruptible Power Supply is a device that sits between a power supply (e.g. a wall outlet) and a device (e.g. a computer) to prevent undesired features of the power source (outages, sags, surges, bad harmonics, etc.) from the supply from adversely affecting the performance of the device.

Q: How do you pronounce "UPS"?
A: Many pronounce it "ups", but most of the literature seems to favor "you pee ess", since they use "a UPS" instead of "an UPS". This document will try to follow the literature. Neither pronunciation will get you laughed at by those who are experienced in the field.


Q: How can it help you ?
A: A UPS has internal batteries to guarantee that continuous power is provided to the equipment even if the power source stops providing power. Of course the UPS can only provide power for a while, typically a few minutes, but that is often enough to ride out power company glitches or short outages. Even if the outage is longer than the battery lifetime of the UPS, this provides the opportunity to execute an orderly shutdown of the equipment.

Advantages:
1. Computer jobs don't stop because the power fails.
2. Have Electricity at home for all applianaces just like normal KPTCL supply
3. Equipments like Tubelights, Fans, TV's grinders, Pump's continue to work normally
4. Provide power for some time after a blackout has occurred.

 In addition, UPS/software combinations provide the following functions

1. Automatic shutdown of equipment during long power outages.
2. Monitoring and logging of the status of the power supply.
3. Display the Voltage/Current draw of the equipment.
4. Provide short circuit protection
5. Provide alarms on certain error conditions.


Q: How long can equipment on a UPS keep running after the power goes?
A: That depends on how big a UPS do you have and what kind of equipment it protects. For most typical computer workstations, one might have a UPS that was rated to keep the machine alive through a 15 minute power loss. If it is important for a machine to survive hours without power, one should probably look at a more robust power backup solution that includes a Solar chargers and Bigger battery banks. Even if a UPS powers a very small load, it must still operate its DC (battery) to AC converter (the inverter), which costs power.

Q: Given the same vendor claims, how can I tell a "good" quality UPS from a "poor" quality UPS?
A: Testing, testing, testing. I can't emphasize this enough. There are many good and bad units out there that call themselves UPSes. There are many good units that are wrong for your situation. Caveat Emptor.
Some properties you might look for include:
1. Sinusoidal power output. In general, the closer the AC output of the UPS is to a sine wave, the better it is for your equipment. Many UPS units, especially the cheaper ones, deviate a great deal from a sinusoidal output. Some of them generate square waves.
2.  Does the UPS have a manual bypass switch? If the UPS is broken or is being serviced, can you pass power through it to your equipment? The last thing you want is for a broken UPS to be the cause of extra downtime.
3.  The more information about a UPSes operation you can get from watching the unit itself, the better. How much power (or percentage load) the equipment is drawing, how much battery life is left and indications of the input power quality are all very useful.
4.  Some newer UPSes can communicate with their monitoring software via a network connection and SNMP. This is wonderful if your network is on a UPS. Also, beware, I have heard of dealers advertising "Network UPS" monitoring where the network is the normal serial connection.

 If you do have a UPS that does not output a sinusoidal waveform, I strongly urge you to not put a surge protector between the UPS and the computer. The surge protector might mistake the non-sine waveform as a power surge and try to send it to ground. This could be bad for your UPS, not to mention your equipment. I don't know if this has happened or not, but I wouldn't chance it.

TOPIC: How big a UPS do I need?

 

Q: How are the "sizes" of UPSes determined?
A: Typically, a UPS has a VA rating. The VA rating is the maximum number of Volts * Amps it can deliver. The VA rating is not the same as the power drain (in Watts) of the equipment. (This would be true if the load were only resistive or the circuit were DC, not AC). Computers are notoriously non-resistive. A typical PF (power factor: Watts/VA) for some computers may be as low as 0.6, which means that if you record a drain of 100 Watts, you need a power source with a VA rating of 167. Some literature suggests that 0.7 may be a good conversion factor, but this will depend heavily on the specific equipment. Moreover, there's really no way to determine these numbers besides measuring them.

Q: How can I tell what VA rating I need for my equipment?
A: First, when possible, get VA rather than wattage ratings.  There are a couple of ways to evaluate your electrical load:

 1. Direct measurement. You can get equipment to measure the current draw of your equipment directly. You may or may not have access to this. If you are part of an organization that has its own facilities/electrical type people, they're likely to be able to do this. They might help you out if you ask nice. If you're on a budget and don't want to shell out for a high-quality ammeter, you might want to dry a device called the "Kill A Watt" electric usage monitor made by P3 International.

2.  Compare notes. If you know someone with the same setup you're using, ask them what they use and how close they are to the maximum VA rating.

3. Use the equipment rating. Most pieces of computer equipment have a power rating on some back panel near where power cord enters the chassis. This number is usually very conservative, as it is necessary for the manufacturer to play it safe or they'll get sued. Also, these numbers generally represent a conservative estimate of total draw of the equipment when it is in its most power-hungry configuration. Typical device configurations may be less demanding.

Generally the 3rd Option is the best and most reliable to get an approx power requirement figure at homes. Please feel free to speak to me in case you require any assistance on the same.

Q: What else should I consider?
A: It would be nice to know how long your site's typical power outages are. In some places, with nice weather and a flaky power grid, the power is almost never out for more than 5 minutes, but this could happen quite frequently. In this case, you may as well use a UPS with a VA rating close to your equipment rating with no extra batteries. If your area has longer outages, in the half hour or hour range, as is often the case in thunderstorm areas like the coastal regions of karnataka, you can either buy UPSes with multiples of the VA rating of the equipment, since oversizing a VA rating for a UPS has the effect of lengthening the amount of time your equipment can stay up in case of a power outage, or you can buy additional battery units for a smaller UPS. You can probably get away with doing simple math to determine how much longer a larger UPS will keep your equipment running, but I recommend running a few tests before committing to a large purchase order.

 
Q: How about I use one of these UPS thingies for a laser printer?
A: Generally, this is not a good idea. If you ever measured the current draw of a laser printer during startup (and during printing) you'd likely be stunned at what it pulls. UPS manufacturers generally recommend that you not do this. Some UPSes are available that are specifically inteded for use with laser printers, but most don't. At the very least, don't do this unless you have carefully sized your equipment and your UPS vendor has committed to supporting this particular configuration.

Please feel free to write to wavedesignsystems@gmail.com on any information you are looking for in terms of technology or business whichever you are interested in.