What is UPS, how does it work, how many are there, how much does it cost, what does it do for me? We will try to solve all these questions in this article, considering that we are aimed at beginner users.
What is UPS
UPS is the vocabulary of words Uninterruptible Power Supply (Uninterruptible power supply). It is a device that provides us with electricity just like an outlet in our home, even if the electricity provider cuts off its connection to our home. In short you have a power outlet that will continue to power your appliances even if your power outage is interrupted.
UPS capabilities usually cover uninterrupted power supply for a few minutes. Do not imagine that it will last an entire night or that you can go for a week off and simply download the power switch of your home. The time offered by UPS is enough to safely turn off a sensitive electronic device and reopen it when the power is turned on. Or until a generating pair, ie a diesel engine, starts generating and supplying electricity as long as its tank is full of oil.
Do we need it?
Your home is full of sensitive devices. Your computer, your TV, your stereo and generally any electronic device is sensitive and requires constant and constant power supply.
But the entire power grid in your home is not as stable as you think. If your provider offers you electricity 230V- 50Hz and if you decide to measure it with an instrument you will see it continuously oscillate from 190V to 250V. It all depends on many factors and that is why each region has its own tolerance. In addition, when the power is cut and restored, you can even measure 500V at the time of recovery.
Not to mention what happens on the net when there is a thunderstorm and lightning outside. Any device that is plugged in can be destroyed in a fraction of a second and your provider will not reimburse you, since a contract between you requires that you have a lightning protection device installed on your electrical panel (which no one does).
In a nutshell, the UPS is an indispensable device for limiting the impact of electric incidents.
How UPS Work
The UPS is nothing more than a simple battery (or batteries) that, through a whole process and conversions, gives exactly that and a home electrical outlet.
Its structure consists of the following main parts:
- The Battery: An Electric Storage.
- The Charger: A device that charges the battery.
- The Rectifier: Converts AC to DC.
- The Inverter: Converts the DC current to AC power.
The third last components are usually an electronic board and it is not unfair to say that, at least for home UPS, they consist of a battery, a board and plastic parts. So in small household UPS, if the board breaks down, you just throw it in the recycling bin.
The operating mechanism of each type of UPS is not the same, but they all follow the following general principles:
- When the utility network is normal: The UPS battery is charged and ready to operate.
- When the room's power cuts: The UPS battery turns into AC power and supplies the electrical equipment connected to it.
How many species are there
UPS is divided into three main categories related to their technology and operation. Let's see:
A. Offline/ Standby UPS
Such a UPS sits quietly in its corner, making sure it always has its battery charged and waiting for power to drop. When there is a lack of voltage then it switches the mains power to the battery. This change, and therefore the lack of power, is needed from 20-100 milliseconds, but is not dangerous for most electronics.
Standby systems are the cheapest of their kind but have the disadvantage of having to switch from network to battery. If you have a UPS and do not write what kind it is, then consider it to be a Standby. Not suitable for hypersensitive electronics, or even for normal sensors, but expensive electronics (servers etc)
It is an Offiline UPS (case A) but with an additional transformer inside and has the following operating mechanism:
Σε συνθήκες κανονικής τάσης, ο αυτόματος μετασχηματιστής δεν θα επηρεάσει την τάση εισόδου. Η τάση και η ισχύς εισόδου και εξόδου είναι ακριβώς η ίδια με αυτή του offline UPS και ουσιαστικά αυτή που σας παρέχει κάθε στιγμή ο πάροχος σας.
When the power supply voltage increases or slightly decreases compared to the default standard limit, the AC adapter will affect the input voltage so that the output voltage supplied to your computer is maintained at normal levels. Therefore, although the power supply of your computer is still the mains of your area, the input voltage and output voltage will be different.
Only in the event of a power failure will the unit eventually disconnect the power supply circuit of the city and switch to the battery circuit. The DC current from the battery turns into AC power.
Ουσιαστικά έχει την ίδια λειτουργία με την περίπτωση Α που είδαμε παραπάνω, αλλά έχει ένα αξιοσημείωτο πλεονέκτημα έναντι αυτής, ότι παρέχει μία λειτουργία σταθεροποίησης της τάσης τους δικτύου και γιαυτό άλλωστε είναι και πιο ακριβά. Ειδικά αν έχετε παρατηρήσει τα φώτα του σπιτιού σας να τρεμοπαίζουν ή να χαμηλώνουν σε ένταση αρκετές φορές τότε το Line interactive είναι ιδανικό για εσάς.
Under normal circumstances, the UPS will continuously switch the AC from your network to DC with an equivalent voltage as the battery voltage and then convert that DC back into AC. It will then give this constant electrical voltage to its output.
When the power supply fails, the unit will use the battery circuit. Battery direct current is converted to AC power to power your equipment.
Χάρη σε αυτή τη λειτουργία, το UPS online δεν απαιτεί έστω και τον ελάχιστο χρόνο για να κάνει την μεταγωγή από ρεύμα σε μπαταρία και έτσι εξασφαλίζει μέγιστη σταθερότητα στην τάση εξόδου. Είναι η ακριβότερη κατηγορία στο είδος τους, αλλά και η καλύτερη.
UPS features and applications
The main job of UPS is to help electronic equipment avoid interruption, damage or loss of data due to sudden power outages. Depending on the purpose of use, and how much electricity this equipment needs, the UPS can range from a simple power outlet to a closet array.
Depending on the design, it can be compact (a box that contains everything), the batteries can be separate and the electronic part can be separate, it can even be modular where additional batteries can be added or replaced at any time, without interruption of power supply.
Also, depending on the power, it can be single-phase or three-phase. For your home the usual case is single phase. Finally, depending on the installation location, it can be a simple box, or it can be made to be placed in a 19 ”rack, or it can be a tower type (tower, like desktop computers) or a closet.
The most serious machines improve the quality of the power source, stabilize the frequency, offer a noise filter, protect against lightning, are equipped with sending reports and have the ability to shut down your computer smoothly before running out of battery.
As a result, UPS is widely used in the fields of information technology, health, industrial production, security and defense.
How much do they cost
The range, as you all know from the above, is huge. The market ranges from very small UPS to huge cabinets. Their cost can range from 30,00 euros to several tens of thousands of euros. Usually a home UPS for a single computer costs from 30,00 to 280,00 euros.
It depends on how good you want and how much time you want to have. But what is autonomy?
What does it do for me.
This is a painful story. That is, knowing your power needs and by extension how much UPS you need. Let's look at two basic technical terms.
The UPS is also measured in KVA (kV). It is a KW (kilowatt) unit of electricity that usually measures the consumption of your electrical appliances.
KW is the actual power that a utility system uses. But every system also has losses. So KVAs are the total power consumption of a system (utility + losses). Supposedly we consider the losses to be 10% of KVA and profitable to 90%. So to see how much KVA the UPS should have, you add all the KWs listed on the device labels that you want to connect to the UPS and then divide the whole by 0,90. The result is the KVAs you are looking for. K in front of VA and W stands for va or watts multiplying X 1000.
So far so good, but with several assumptions. First of all, the signs refer to the maximum consumption of the machine, which will probably never reach that number. Especially on computers, consumption is measured by the KW of the power supply, which is usually well above demand.
Let's go over this part for now and go below. UPS usually when reporting how many KVAs it is, estimates that if all these KVAs are required then the machine will last about 5 minutes. If you want more, then the hardships begin. Each UPS is accompanied by a performance curve or a table where you can find how many minutes the UPS will last depending on how much Watt or KW load you have connected to it.
You can find such tables on the manufacturer's website. For example, its UPS APC BK500EI can power your devices for 3,9 minutes if they have total 300 Watts consumption or for 24 minutes if your devices are consuming 100 Watts.
So you can easily choose a machine as long as you know your Watts of consumption and how long you want autonomy. For simple home cases with a desktop computer, an LED technology display and an injectable printer, a UPS 500 VA will keep you around for 13 minutes and cost you from 42,00 to 170 euros.
What about maintenance?
UPS does not have as many requirements as your computer. They can withstand much higher temperatures and humidity. So, first the computer will "hit" and then the UPS. But be careful not to cover its ventilation holes and do not wash it with coffee.
It has electrical protection and rarely burns but if you bring it down it will give you up. Be careful how many outlets it has, make sure it reaches you and check if the ones you use are battery-powered and not just mains sockets.
Finally his battery (s) want replacement every 2-3 years. Replacing a home UPS is usually a simple matter. Requires a crossbow and your hands to catch a little.
Σβήστε το και βάλτε το από την πρίζα, ξεβιδώστε το καπάκι της μπαταρία και ξεκουμπώστε την μπαταρία από τα δύο καλώδια (κόκκινο και μαύρο). Αμέσως μετά πατήστε το κουμπί ώστε να ξεφορτίσουν οι πυκνωτές για θέμα ασφαλείας. Αντικαταστήστε την μπαταρία, επανασυνδέστε τα καλώδια στην σωστή θέση (το κόκκινο στο + πόλο της μπαταρίας), βιδώστε το καπάκι και τελειώσατε.