Database of UPS inverter output waveforms (updated)

Others (G-Z)




Line-interactive UPS with sine wave output, labeled power 1.5 kVA/900 W. The OEM is Ablerex. Capacitors in charger go bad and then it stops recharging batteries. Be extremely cautious while doing hot-swap change of batteries, they flow against the earth grounding (and UPS metal casing)! Newer G-TEC units are mostly of Must Power origin.



This is quite interesting unit a the brand is one of local major ISPs. I did not know they ever had any UPS series, it is possible it was just for their internal use. Anyway, I have identified this unit to be basically identical to russian Powerman Black Star series and also the SW application Powerman provides works with this unit. I am not sure if it is Powerman OEM’d, or they share third-party OEM, but they definitelly are the same. The internal electronics is somewhat poor, potentially hazardous if you ask me. It is line-interactive 1000VA/600W unit with square-wave output, as could be expected.


Even with new Panasonic 9Ah accumulators it only lasts about 5 minutes at full load and the transistor heatsinks get incredibly hot so also some modding in this regard was also necessary. The reason is that it uses unusual configuration with two tranformer windings, one fed from each accumulator, so while each accumulator only provides half the current, together it works with up to 60 A at only 12 V (nominal). Despite that it has reasonable peak efficiency of about 80 %. The only good thing is the unit uses metal chasis so you at least have somewhere to conduct all the heat- should you decide to make the improvements – in factory state it is an ordinary El Cheapo. Idle power draw is just around 19 watts but also the charger (based upon LM317 linear regulator, at least it has decent heatsink) is quite weak so it takes about 14 hours to fully charge the unit.


T750 G2

Line-interactive model rated at 750 VA/500 W with sine wave output (which is not that very clean though). It reminds me of some Ablerex units, but I cannot confirm whether this company is the OEM, or not. Not yet anyways. Idle power draw is about 19 watts and efficiency under full rated output aproximately 79 %.

T1500 G3 (T1500 INTL)


Line-interactive 1.5kVA/950W UPS with sine wave output. Quite an honest peice of hardware with a fan and three accumulators.


Integra Tech

E-Plus 1500


Another plastic brick from Must power, same as all the others. This 1.5kVA/900W version from Integra Tech has a fan and some incredibly no-name batteries which failed after only two years. Such batteries often lose their seal and the electrolyte escapes, where it may damage other parts of the device. Also it has bad capacitors and it is very difficult to solder that cheap PCB material Must Power uses.


Heat Master 200/F200


Once again a Must Power unit, you can tell that from the display used. This time however, it is in metal enclosure and with low power of only 250 VA/200 W. Recommended for central heating pumps, it has two internal 9Ah accumulators as well as the possibility of using external ones. It lacks fan and is actually a stepped approximation to sine wave unit with added module to bring the waveform closer to sine wave. This will not hurt motors so much as the waveform these units normally provide, but it is still far away from true sine wave. Another component which may fail inside already problematic chinese unit, I would not buy such a thing.





The Powerbank EH-500L provides 500VA/300W of sine-wave power. These are line-interactive units using external accumulators up to 200 Ah which they can charge with high-power charger (up to 16 A). They handle inductive loads well and are often used for central heating pumps. With 100 Ah accumulator the idle power draw is about 25-35 W (depending on accumulator capacity and whether the fan is on). With such spread of usable accumulators (17-200 Ah) it varies as larger accumulators have higher leakage currents, resulting in higher consumption. Efficiency peaks at roughly 70 %.


The charging is quite regularly pulsed, possibly an attempt at desulfation.



5115 1400i (PW5115-1400i)


Powerware, later acquired by Eaton, model 5115 1400i provides 1.4 kVA/950 W. Supposedly hot-swap accumulators replacement, but in real world it is somewhat difficult to get to them while in operation. A line-interactive unit with more or less sine wave output.


Prestige 3000 2000 VA (2000P3HV)


Two-part on-line UPS (external accumulator cabinet in the same plastic case). The power unit itself has turbocooling with multiple high-speed fans, sometimes even used in series. Few of them survived so long, they are quite faulty. Labeled power of 2 kVA, possibly 1.4 kW.


9120 (PW9120-2000i)

The on-line unit (Eaton) Powerware 9120 (PW9120-2000i) is likely a next generation product replacing the Prestige 3000 above, from around the 2000s. Rated at the same 2000 VA/1400 W, this time it comes in ordinary metal chassis which includes the 9Ah accumulators (8 pieces, 96 V nominal). Being an on-line (=double conversion) unit, the no-load power consumption is about 60 watts, which is not that bad, also considering the two rear turbines run constantly.


NEtDialog 2000 (NDG 200)

Older office unit rated at 2000 VA/1200 W. Outputs just the ordinary moddified square wave. It is quite similar to all the Must Power&Co. craps, however, it is not any familiar PCB so likely made by some different chinese OEM. Still quite crappy though, cheapest PCB and other materials, likely aluminium transformer winding as it consumes humongous amount of power – almost 50 watts. For this reason, its fan runs all the time to keep the transformer at least somewhat warm (instead of burning hot). Efficiency under full load peaks around 83 %, but with just three 9Ah accumulators it could not provide the power for more than a minute.


SLC3000-Twin Pro


An on-line UPS with power of 3 kVA/2.4 kW.





Generic plastic brick most likely of Must Power origin. Both units I received had deformed plastic body under the main transformer from excessive overheating, I suspect aluminium windings again. Nominal power of 800 VA/480 W, but heavily underrated, with only a single accumulator it handled less than a minute of 400W load. With full load you won’t even turn your computer off on time before it dies completelly.



Intelligent UPS 650 VA (PP200)


Sweex PP200 is another Must Power plastic brick unit with single accumulator. Labeled power is 650 VA/360 W and of course usual modified square wave.


The charging pulses are quite hardcore.


Intelligent UPS 1000 VA (PP210)


More powerful and bigger version labeled 1 kVA/600 W. Completelly identical to many other units/brands. Uses two accumulators and for sure an aluminium-wound transformer. Passive cooling only, runs quite hot. Waveform is modified square wave. Idle power draw tops slightly under 23 watts.


Intelligent UPS 1500 VA (PP220)


This one is labeled 1.5 kVA/900W, has two 9Ah accumulators and fan, otherwise the same hardware.


Trueful Electronics Corporation

EPS-300PII (Conrad Power Manager Mini NSV 300)

Labeled Conrad in the front, this unit was actually made by Trueful Electronics as the back label states. It is msot likely the tiniest UPS I have ever seen, I barely squeezed the accumulator inside without blowing a hole to it. This is ancient and off-line 300 VA/200 W unit made around 1994. Maybe just older components have been used and it was actually introduced in 1997 with Pentium II systems (as the PII in the name would suggest). After replacing all the capacitors and making some improvements (using safety rated Y capacitors, thicker accumulator wire etc.) I still had some troubles with its sensitivity when the unit was switching to inverter and back like crazy. After many hours of study all it took was to slightly shift the only variable resistor in the unit, now it works OK. With 9Ah accumulator it takes about two days to fully charge as it has just a weak and inefficient charging supply (utilizing its small iron-core transformer). The inverter output is square wave of course. The idle power draw is about 9 watts.



NetPro 3000+


Old Victron on-line unit labeled 3 kVA/1.8 kW. Sine wave output of course.


Volt Polska


Sinewave unit labeled 800 VA/500 W. Appears to be quite popular for backing-up heaters (furnaces) and boilers (gas or coal fired) together with their circulation pumps. Judging from the internals, the OEM design is based upon the usual Must-Power-or-similar stuff, although using decend PCB material at least. The unit uses toroidal transformer (with several windings for different purposes) and linear drop-down regulators, which is quite reliable on one hand, but quite ineffective on the other.

For that reason, while the idle power consumption is still acceptable at 12,3 watts, during charging with 10A maximum current, all the losses take effect so rough efficiency is well below 70 %. Inverter efficiency at (close to) maximum load is not great either, slightly over 75 %.

Source: inlandpolitics, DiiT, Esa Tuunanen

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