Database of UPS inverter output waveforms (updated)

Others (A-F)




On-line rackmount unit labeled 1 kVA/700 W. Ablerex is the original manufacturer. Idle power draw ranges from 20 to over 70 W as the PFC cycles so the true value is somewhere between.


AEC (Armen Electric Corporation)

Star T3 3 kVA (ST-3100)


High-power on-line (double conversion) UPS, 3 kVA/2.1 kW. Battery cabinets may be stacked, but with just one cabinet the recharge times are already very long. It MUST be closed during loading otherwise it overheats.





Smaller grey brick with french outlets (type CEE 7/5) with power of 800 VA/450 W. Line-interactive with two accumulators, what a coincidence the output is similar to one of those APC Back-UPS RS 800 VA units.


Best Power Technology

Fortress LI 660 VA (QLI660VA)


An antique UPS, most likely line-interactive. Labeled power 660 VA/400 V. After 13 years the driving logic was not able to operate anymore with unknown brand c(r)apacitors, after replacement with quality ones it operates normally again.


It is impressive how close this thing is to a sine wave. On the other hand, battery charging is quite rippled.



PowerLan Plus 750


A UPS from times when back-up time still meant something, 750VA/525W model with four accumulators (2×2 in series). Line-interactive with sine wave output. It is a small horror to get to the batteries.



Professional Rackmount LCD Series 1500 VA (PR1500ELCDRT2U)


An on-line rackmount 2U UPS with power of 1.5 kVA/1 kW. Uses low-profile high-power type-A relays, it is difficult to get spare ones. Probably of Must Power (or similar) origin, I personally do not trust these OEMs.




The low-end and very cheap CyberPower units are – unsirprisingly – made by Must Power, pretty much as almost everything else in this price segment. It is dirty cheap and dirty bad 600VA/360W unit, line-interactive. Well, not that bad actually, unlike older units from Socomec, this one was at least capable of providing almost full power: with 340watt output it managed to do 1 minute and 2 seconds with brand new Panasonic 9Ah battery. One would expect at least five minutes, but than it is still better than less-than-a-minute which Socomec showed, here you have at least a chance to turn your PC off. But it is mostly the craziness of sucking over 30 amperes from single battery manufacturers do which results in so short runtimes. Modified sinewave output as usually, idle power draw 11.5 W.



3105 350i


The Eaton 3105 350i is a low-end unit with integrated accumulator which provides power of 350 VA/210 W. It is of course an off-line model with modified square wave, you can see the output quality with long periods of almost zero voltage.


Ellipse ECO 1200 USB FR (EL1200USBFR)


Line-interactive standing UPS with Schuko outlets (so not a FR for sure) with that EcoControl-thingy, whatever that is. Provides 1,2 kVA/750 W. Waveform is modified square wave, somewhat better than in the case of 3105 and it can truly work with some 500watt ATX PSUs with active PFC and another kilowatt in non-backuped plugs. More load trips the integrated circuit breaker.


Nova AVR 1250 (66824SG)


The Eaton Nova AVR 1250 is an older, now EoL’d line-interactive series. On first glimpse it reminds me of the Must Power units, but the internals are completelly different. It seems that these units may have something in common with the MGE Nova AVR models from MGE UPS Systems which Schneider Electric had to sellto Eaton when it acquired the APC. The electronics of this unit is very simple though it uses quality PCB at least, the UPS also has much larger transformer (with true copper winding). It is rated 1250 VA/660 W. Its fan is constantly-running though. The output is the usual square wave and the idle power consumption is slightly over 29 watts.


5E 850 VA (5E850iUSB)

With the 5E (aka essential) series Eaton is most likely trying to compete with all the chinese plastic craps from Must Power (or similar ones as they all look alike). This unit also looks quite similar to most of the others and it is very likely they actually have it made on separate line, or possibly they bought some of the chinese fabs to produce these wonders for themselves. The design is likely theirs as the board appears different though. As the others, this wonder uses the el-cheapo board material with so thin paths (who knows whether is is even copper, or how pure), very difficult to solder or otherwise work with. Filled with Jamicon TK crapacitorsa nd often garbage accumulators (such as Leoch). There is also large transformer with large (but light) iron core and aluminium winding for sure to make it as cheap as possible. The 5E850iUSB is rated at 850 VA/480 W.

The modified square wave looks like exactly the one from the Must Power units we’ve seen sold under many brands. There is not really that much to invent on modified square wave, but these waveforms look pretty much the same still. The idle power draw is quite low at just about 13.7 watts, which is nice, however Eaton just promises something not capable of providing regarding the rated power. Their own loading diagram ends at some 375 W and 1 minute runtime, with full load it goes down in just a few seconds and that’s with brand new Panasonic 9Ah accumulator. That’s quite obvious as the efficiency I managed to quickly measure was not even 60 % with current reaching over 55 A – single accumulator of this size can not provide that, the voltage falls down very quickly. With just 315W load it worked for like 2 minutes with 66% efficiency. For me this is terrible to see how deep Eaton is willing to sag. Not that APC is much better with their latest generation of cheap units, but…I would expect some decency from certain brands to just don’t cross some line. Guess that money does not stink, eh?

5E 1500 VA (5E1500IUSB)

This is slightly larger version rated at 1500 VA/900 W. Again filled with Jamicon TK crapacitors, linear voltage regulators burning lots of power (so the no-load consumption is around 20 W) and garbage Leoch accumulators. It only held about half the specified runtime (granted, it was slightly overloaded).

The modified square wave looks like pretty much the same as the 850VA variant above outputs.

5SC 750 VA Tower (5SC750i)


Modern line-interactive brick with pure sine wave output. Equipped with advanced electronics, it strongly dislikes induction load (2kVA separation transformer not without any other load, not with 40W light bulb on the transformer secondary, not in parallel with its primary) so this one seems to not be good for motors. I don’t know where the problem was but I have only seen half-waves in there.



Modern line-interactive series with sine-wave output. Capacity of 1550 VA/1100 W.


PowerSure PSI PS1440RT2-230


Emerson, now Liebert, rack-mount model of 2U size, line-interactive with 1.44 kVA/1.08 kW output. Sine wave.




Eurocase EA620, aka rebranded East EA620, labeled as line-interactive sine-wave unit with 2000 VA/1600 W capacity. While the inverter is able to provide such power, for a limited time at least, only three 9Ah accumulators definitelly are not at all so do not count on more than couple tens of seconds. At least the H variant of this model with four accumulators (48 V nominal) is needed for any decent runtime, or the East should rate it lower at aprox. 1500 VA/1200 W. Also while the PCB is not such a garbage as one would expect from unit of this price, the transformer with aluminium winding definitelly is, for that reason the idle power draw is huge: 47 watts. For this reason its fan runs constantly and even than the UPS smells when new. We measured efficiency around 78 %. Also the front panel buttons are quite insensitive (and you must press two of them simultaneously for many actions on top of that).

FSP Group



I first thought FSP would be manufacturing their own uninterruptible power supplies, but I could not be further from the truth. Well, it depends, I heard FSP has some share in the manufacturing company, supposedly Must Power. The EP family consists of blue/black models with just LEDs, no display. These units have very simple and cheaped electronics, they often suffer from overheating LM7812CT linear regulator baking surrounding components. It has capacity of 1000 VA/600 W, only passive (thus very bad) cooling. This particular piece also had some polish LEOCH batteries which failed in less than 3 years, leaked and have completelly eaten through the wire connecting both batteries.


The ordinary simulated „sine wave“. Sine wave in their dreams maybe. Thanks to poor efficiency, the output voltage is low and because of the waveform, even incandescent light bulb is visibly flashing.



The blue/black or black FSP PP family is one of the many OEM versions of plastic chinese Must Power UPSes (which come under tens of other brands). This versions comes with LCD but the electronics is the same in both cases. This is 2kVA/1.2kW version with integrated fan, but it still runs quite hot and has bad efficiency as the main transformer has aluminium windings, both primary and secondary. All these chinese units share such transformer. This unit had Yuasa batteries which failed in 3 years anyway. Modified square wave output.


Galleon 3k


The FSP Galleon is on-line UPS labeled 3 kVA/2.4 kW, of course with true sine wave. OEM is possibly Must Power again, or some other chinese company.

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