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Everything about UPS.

TechEkspert 16374 50
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  • #31
    alojzy7719 wrote:
    I need a UPS to power my music equipment from an external soft-start power supply. The online topology UPS (for about PLN 1000) did not work (the equipment did not start, only the LED in the power supply from the above-mentioned equipment was flashing - probably due to the simulated sine wave). Will UPS Line Interactive AVR pass the exam?

    Line Interactive AVR (generally speaking) is inferior to Online UPS (VFI).
    If the VFI UPS was not suitable then it probably was not the online VFI UPS or there is some other problem.
    The price is also different than the online VFI equipment (for example, UPS RACK 2U 1000VA with batteries ~ 10 minutes costs about PLN 2,500).
    If you want the UPS to be VFI all the time (output voltage parameters independent of frequency and supply voltage), disable the high efficiency options (if available), as they often involve starting an internal bypass and turning off the inverter power stage. For double-conversion operation, the output voltage comes from the inverter powered by the DC bus. Power to the DC bus is supplied by a rectifier (when the supply voltage is present) or by batteries (when a power failure occurs).

    When operating the UPS 1f "in the field", check the correct power supply of L and N cables and, of course, the continuity of PE (some models indicate incorrect connection). It is worth paying attention to this detail because the N conductor inside the UPS is usually a non-detachable connection (sometimes there are LC filters on it). All connecting elements (including the bypass) are located on the L cable. It is easy to notice that unfavorable effects may occur with an incorrect power supply.
  • #33
    The device in the link is not an online UPS (VFI).
    On the same page there are also devices powered from 12V, for 24V it would be required min. e.g. connecting two 12V batteries in series.
    Generally by in the description, these are devices with AVR functionality, they are probably equipped with basic overvoltage protections, but I would treat them as a type D arrester (perhaps C, but it is unlikely). Anyway, failure to precede the UPS with appropriate protectors will not protect the loads against surges.
  • #34
    Level 36  
    Thank you for your answer. What kind of protectors would I have to use before the inverter?
  • #35
    If you want to reduce the risk of damage from overvoltages, then:
    1.If the UPS / converter is not equipped with overvoltage protection, and the facility has a B arrester in the main switchboard and a C arrester in the multi-storey switchboard (or there is B + C), then a D arrester can be used.
    2. if B + C or B and C is in the facility and the UPS provides protection such as a D arrester (usually it is so), then nothing needs to be done.
  • #36
    Level 33  
    As for the grounding + on the telephone exchange, it is designed to protect the cables from corrosion in the event of insulation damage. They did not write this in this answer, but I asked a specialist from the headquarters a long time ago.
  • #37
    Level 15  
    Has anyone come across really high-power UPSs, e.g. 500kVA with a programmable / adjustable soft start characteristic? I mean such a situation that:
    1.After a power outage, the UPS was sending electricity to the receivers
    2. I run a power generator with a capacity not much greater than a UPS, approximately 700kVA
    3. I connect the UPS to the generator. The characteristics of the motor are such that it can be loaded up to 30% of the rated power at one time in order to maintain the U and f parameters as such.
    4. I need a UPS that will gradually load the input to the required power.

    Maybe someone has such a soft start characteristic of such a UPS, because it may work, it will stimulate a little with voltage and frequency at the input, but it will stabilize.

    In the UPSs available on the Internet and known to me:
    - EVER
    - APC
    - EATON

    I did not find it ...
  • #38
    A very interesting question, in smaller UPSs, e.g. EATON 93xx series,
    the specification includes the following:
    Soft start capability: Yes

    I have not encountered the possibility of programming the time and soft start characteristics.
    If the above-mentioned UPSs lack such functionality, you can ask e.g. Socomec (they developed new technologies),
    Recently, I was surprised that the UPSs are also produced under the brand Legrand also worth asking, maybe they are open to new solutions.

    I am curious if it will be possible to find a UPS with a programmable function of gradually loading the input with load power after the power is restored.
    If you can, let us know about the results of further searches.

    Do these 500kVA UPSs work on a common bus? If not, maybe it is possible to attach receipts in sections?

    The 0.7MW generator takes a while to get the rated power, is it correctly feeding the ATS, maybe the ATS switches the load too early?
  • #39
    Level 14  
    TechEkspert wrote:
    It is a mandatory condition only for 48V power systems in telecommunications, in other 48V power systems there is no such obligation.
    The grounding of the DC system other than the 48V telecommunications power plant can be done on a voluntary basis, but after making sure that there are no fuses or other protections in the grounded power path.

    So the earthing (positive pole) from such a battery with a voltage of 48V, a link to the earthing bus and the PE wire from the inverter (UPS) which gives me, for example, 230VAC and power xx kW I also plug in there? Is this solution correct?
  • #40
    DC telecommunication loads and UPSs are two different systems, both devices will have a ground connection terminal, looking "from the side" of the PE conductor, both systems will be connected to it in the manner provided by the manufacturer.
  • #41
    Level 6  
    How could I calculate the UPS runtime on battery power,

    I mean specifically about sustaining 250W for 2 hours.

    What UPS would be a sufficient solution?

    best regards
  • #42
    250W for 2h is 500Wh.

    The question is whether this device is powered from 230V?

    If so, let's assume that we have a small UPS powered by a single 12V battery.
    It is easy to estimate that at 12V and 500Wh the battery capacity is about 42Ah.
    Unfortunately, with this power, the battery current will be quite high (~ 20A).

    For a slightly higher power UPS, there will usually be 4 batteries and at 48V the capacity of one battery should be around 11Ah.
    The current for such a set of batteries will be less, more than 5A.

    Of course, as you will find here: VRLA the voltages of the batteries will be higher than those stated above.

    In addition, there are processing losses and, for example, 12V 42Ah can be 52Ah or much more, and with 4x12V 11Ah, for example 14Ah or more.

    If the device (s) has a power supply, e.g. with a specific DC voltage, e.g. 9-12V, a better solution may be a buffer power supply + or a high-efficiency DC / DC converter at the output.
  • #43
    Level 6  
    Thanks for the answer,

    Yes it is 230V

    However, I am surprised that you add up AH with 4 12V batteries giving 48V, i.e. connected in series. It seemed to me that AH in series connection do not sum up only in case of parallel connection.

    It is hard to find a 12V battery of your choice on the market, usually 7AH or 9AH. Still need to add this value?

    Many thanks for any comments.
  • #44
    Administrator of HydePark
    So1dat wrote:

    However, I am surprised that you add up AH with 4 12V batteries giving 48V, i.e. connected in series. It seemed to me that AH in series connection do not sum up only in case of parallel connection.

    Of course, you are right.

    Go to the APC website and look for "active plots" for each model.

    For example, I have an APC-SMRT 750XL (2x12V 17Ah). The equipment that powers it loads it at 33% and the backup time is 75 minutes.

    Added after 12 [minutes]:

    I looked at the APC website and it comes out that you need an APC Smart-UPS XL 2200VA UPS, and the specific model is SU2200XLINET
    At 250W, you have 148min. 4x12V 17Ah enters there.
  • #45
    The ampere-hour reserve in identical batteries connected in series does not add up,
    but the tension is
    and thus also the watt hours are added up, which means that having, for example:
    - a 12V 7Ah battery powering the converter generating power for the system, we have at the ~ 84Wh input
    -but at the 4x 12V 7Ah battery pack, we already have 336Wh at the input
    This, of course, is only an approximation to show what's going on.

    When we use standard UPSs with built-in batteries, the power and price of the UPS will also increase as the hold time increases.
    Another solution may be a lower power UPS but with an external additional battery pack that will extend the operating time.

    In the event of a possible modification of a UPS with a lower capacity, there are some problems to remember:
    - the charger system may need to be adapted to the large capacity of the batteries
    -UPS may not be adapted to long operation (e.g. cooling), as standard batteries discharge e.g. in 15 minutes ...

    Does it have to be AC and 230V? :) (e.g. circuit pump AC motor).

    However, can it be DC adapted to the power supply of the receivers and their internal structure (usually another DC / DC converter)?
    Avoiding voltage increase and AC generation would help to significantly reduce losses.
  • #46
    Level 6  
    I would like to connect to the topic if the Author does not object and maybe even uses his advice ..

    I have ups online model: Socomec UPS NETYS RT 7000VA / 5400W

    I know that it works with 16 external batteries with a voltage of 12v 5Ah. When combined, they give 192V with a power of 5Ah.

    It is also possible to connect one more package, i.e. another EBM unit with the same parameters, I think
    ? I've read so much. So a total of 32 batteries with a capacity of 192v and 10AH ?? Because something is not the mode ..

    And I have an idea to make a small off-gride based on this unit.

    Theoretically, it writes on the housing on the back that you can connect the maximum 192vdc with a voltage of 21.5 at (5kva) or 30A (at 7kva).

    My idea is to connect it with pv panels that would supply batteries in a buffer system ..
    But how to work around it to use the existing ups or possibly what would be needed to make the idea work ...

    Because I understand that there is everything in this unit, i.e. a charger, etc.
    And if I wanted to combine it with panels, how would it look like it wouldn't burn anything?

    The connection of the panels so that they oscillate within the limits of 192V or more and the regulator, I think right?
    PV specification
    Current at mpp: 8.11A
    Voltage at mpp: 30V

    The UPS would, of course, be disconnected from the ZE network .. Please advice how to bite it ..

    Ps. Well, the second question, possibly, what would it look like if I would like to have the possibility to connect an aggregate like this (2.5-3Kw) .. on cloudy days when the sun would not give energy.

    I messed up a bit but I hope everything is understandable and quite legible ..

    Thanks in advance for the reply and any suggestion ..

    Best regards.
  • #47
    Is it possible? probably yes, but if the UPS allows you to connect and configure 1 EBM, it will not "know" that there are 2 EBMs and, for example, it will show the expected operating time incorrectly, the charger will charge the battery strings longer, cooling the UPS may be a problem with extended work charger / inverter, there is also a chance that some charging error may occur (e.g. too long charging time if the UPS has such capabilities, although it is less likely).

    The second part is more difficult, i.e. buffer charging of PV batteries,
    it is best that the PV installation supplies an inverter that will supply the UPS with mains voltage and the UPS will charge the batteries with its charger.

    PV inverters are most often adapted to work in synchronization with the grid and here is the problem because you want to build a system that works outside the grid.

    Of course, charging the batteries from PV is theoretically possible, but it requires a lot of attention not to lead to problems, the amount of work can be quite a lot ... experience is required, caution and I do not know if I would do it ... DC from PV can be dangerous, just like energy stored in the AGM battery string.

    I would be more inclined to install with an inverter that can work without the mains, but usually it will be able to work with batteries, so UPS becomes optional.

    A power generator, if it has the appropriate parameters (voltage stabilization), could supply the UPS with mains voltage and recharge the batteries.

    Generally a research topic ;) you would have to count how much energy you need, how much can you generate as the balance comes out. Does it have to be 230V AC or maybe the loads can work with 12 / 24V DC etc.

    I propose to start a new topic because we are actually starting to slowly leave the UPS area.

    The topic is quite old, I can see that UPSs with LI-ion batteries appear more and more boldly in the meantime, besides, most of the information from the first post is still valid.
  • #48
    Level 6  
    Thanks for the answer..

    Ultimately, 10kw on-grid will be in the house anyway. Although I would prefer to have a hybrid .. And the problem would be .. So much that the hybrid inverter costs 2 times as much as in China, and in turn from China I will probably not be able to report it to the ZE because certificates and all papyrology, etc., because I would probably be tempted .. I read, and the farther into the forest, the darker it becomes, balancers, regulators, etc., and usually everything up to 48V, because higher DC can kill .. If nothing makes sense, I will separate a line for the UPS- and I will charge the battery through his own charger .. He is naturally adapted to 2 EBM, so errors will not be poured .. And from poverty, when there is no electricity, these 2kw, if I count well in the battery for a while, and as for the terrain, the generator + battery should be able to do it ..
  • #49
    Level 14  
    Yes, from my own backyard, I have a 5kW MPPSolar inverter (basically it's a UPS with the possibility of connecting PV panels) one phase with an 18kWh battery and the battery voltage is from 56V to 40V, additionally (especially now, at this time of the year), recharging these batteries is from the 2nd tariff (such a simple timer and contactor). There are not too many panels because 7kW. For my 4th person, the family is just right. I recommend alkaline batteries, they especially like long discharges, so for me they fulfill their task perfectly. I've been using it for 4 years now. This year I added about 5l of electrolyte to all batteries, which is not a big cost, in 5 years I will have to change the electrolyte, charge and then another 10 years from the head. I keep wondering why people don't use alkaline batteries.
  • #50
    I have never used, or even seen a live alkaline battery with topped up electrolyte ...
    Maybe you can write something about your experiences and about alkaline batteries in general in articles ?
  • #51
    Level 14  
    TechEkspert wrote:
    I have never used, or even seen a live alkaline battery with topped up electrolyte ...
    Maybe you can write something about your experiences and about alkaline batteries in general in articles ?

    Basic Ni-Cd batteries with KOH electrolyte
    KPL, KPH, KPM, such a series, depending on the application, appropriate types are used. The best is KRH, and as in the case of acid, you can draw a lot of electricity without harm to the battery.
    And this is how it looks with me, you have a photo and a catalog card because I was buying from them.
    For me, they work in conditions from -10C to plus 28C - this is the maximum temperature that I have recorded over the years, cold is not afraid of heat, it's important not to overload, and so you forget about their existence for a year. As cooler, I raise the charging voltage, and warmer I lower it. The most important thing is that they are the most durable on the market and the average number of discharge / charge cycles is (in my case) 12000. The disadvantage is the loss of 5% of energy while charging, a lot of weight, but for me it does not matter.