PurePower 3000 AC Regenerator Review

[Geert]

I like to see that NEC code section, The recommended NEC max voltage drops are Fine Print Notes that are not enforceable. (only recommendations.)

Recommended is exactly what I said.

 

[Geert]

În a winter days I have sometimes 160Vac. The street electricity grid was very weak, probably because the step-down transformer was undersized for winter consumption. Without the UPS the audio system wouldn't even turn on. With the UPS inserted into the system, the audio system worked flawlessly.
About five years after I moved there, the poles, power lines, and transformers were replaced and now things are going well.

OK, but that's a different story then mains power grid output impedance is audible. It’s what I referred to as an edge case, where an UPS or regenerator can help indeed. Most western countries have regulations for mains grid voltage tolerance, something like +10% / -6%. That’s why they fixed your problem eventually.

 

[DualTriode]

What these generators are mostly about is mains voltages dropping waaayyy below the nominal value or increasing above certain levels (so poorly regulated mains for whatever reason). In that case the output voltage remains stable and does not sag.
This may well be beneficial with equipment using linear power supplies.

Forking out $ 5k is a lot to fix that. There are probably cheaper regenerators around,

I worked at the Facility Design and construction department at a large 500 bed hospital and many Medical School Labs and teaching facilities on a 110 acer campus. The three largest electrical loads on site 1) were fans, compressors and motors in general 2) lighting and 3) computers. Most every building had a emergency generator. All these systems had power supplies that were not so linear. All the step-down transformers were K rated to handle the Harmonic Distortion caused heat created by the not so linear power supplies. Some of the early generation VFD's, Variable Frequency Drives, were so sensitive that they would trip off line when the utility would switch in Power Factor Correction capacitators. The heart catheterization lab computers would drop off line due to the HD's and spikes on the hospital power system. The large 3-phase power supply isolation transformer for the Cath Lab did not workout so well. Turns out the cath lab equipment power supplies were the source of lab's own problems.

See the ABB white paper attached below for good discussion of dirty power and good graphic illustrations.

https://search.abb.com/library/Download.aspx?DocumentID=1TQC194900E0001&LanguageCode=en&DocumentPartId&Action=Launch

 

[kyuu]

As I said in the review, I plan to test some "solar generators." I like them better because they use lithium batteries unlike the unreliable lead acids still used in UPS systems. I just haven't had the time to test the two I have.

For home use, those "solar generators" are quite adequate. However, there are certainly "proper" UPSes that use LiFePO batteries these days. APC has some, but they are outrageously expensive. I'm actually in charge of the UPS systems at my place of work, and due to APC wildly overpricing their LiFePO options I'm in the process of transitioning over to Vertiv Liebert as they age out. We primarily use their line-interactive models, but they also have online double-conversion models. They're reasonably priced, IMO, given the advantages of never needing battery replacements, more reliable runtime during outages, and being so much easier to handle for installs.

 

[Svend P]

When I worked with off shore wind turbines, we had issues with circuit breakers tripping from over harmonious currents, even when the actual load was below the rating of the breaker.

The internal 230 V supply in the turbine was full of noise from the converter. As far as I remember it was around 10% - it was certainly a lot more that what was allowed in the grid. Some circuits were supplied through an APC smart UPS, and they did not experience any problems. It's only job was to keep the controller online for 24 hours in case of a grid failure, but the filtering turned out to be a welcome side effect.

Later models of the turbine had a choke installed to remedy the problem for all circuits.

 

[milosz]

That's a very beautiful suit of clothes, Emperor sir....

 

[gpauk]

Regular UPS sends the incoming power to output so other than some rudimentary filtering, it doesn't do anything. There are some online, dual conversion which do something similar but I have not measured any. They tend to be more expensive although likely not this expensive.

As I noted in the review, I plan to test the new power plants that have become so popular now. Will see what their power quality is.

All the UPS we use do not do this. They generate a sine wave AC out all the time, this is powered by battery or incoming mains if it's there. There is no direct path

 

[Fleuch]

When I worked with off shore wind turbines, we had issues with circuit breakers tripping from over harmonious currents, even when the actual load was below the rating of the breaker.

The internal 230 V supply in the turbine was full of noise from the converter. As far as I remember it was around 10% - it was certainly a lot more that what was allowed in the grid. Some circuits were supplied through an APC smart UPS, and they did not experience any problems. It's only job was to keep the controller online for 24 hours in case of a grid failure, but the filtering turned out to be a welcome side effect.

Later models of the turbine had a choke installed to remedy the problem for all circuits.

My understanding is that wind turbines require an external supply for excitation from the grid, which explains why wind turbines cannot contribute to a black start up following a grid failure. Also I understand that wind turbines, and solar panels, generate at DC which is then inverted to AC. Although inverter technology is always improving, it is unlikely to produce a pure sine wave.

As renewable penetration on the grid increases, will the additional harmonics at the wall plug significantly affect the performance of power supplies used in audio - or just require a larger capacitor across the power rails?

 

[dasdoing]

Then I suppose class D amps can't generate a sine wave?

A simple PWM UPS typically produces a modified sine wave (basically a stepped square wave) because it's easier and cheaper to generate using basic pulse-width modulation. True sine waves require more sophisticated control of the PWM duty cycles plus filtering to approximate the smooth AC waveform.


With high-frequency PWM and precise modulation, it’s absolutely possible to approximate a sine wave very closely. The PWM signal gets passed through low-pass filters (like inductors and capacitors) that strip away the high-frequency parts, leaving behind a smooth sine wave.


There are a few reasons why many PWM UPSs don’t do this:

• Cost constraints – adding proper filters and high-speed switching components makes the UPS more expensive.
• Component stress – generating a clean sine wave requires more robust electronics that can handle the load.
• Target use case – budget UPS models assume you’re mostly powering stuff that doesn’t care about power quality (like PCs with switching power supplies).

That said, most modern "pure sine wave UPS" units are actually PWM-based internally. They just use more advanced modulation and better filtering to deliver a true sine output.

 

[dasdoing]

Definitely not better, research the types of ups, that one is cheap crap.

I actually searched for an online type, so I thought this would be. but it is not, correct.
I was misled by an algo. but your example has 3.5 stars

it is also not cheap crap. not everybody needs an online type. I don't need my sine-wave to be perfect.

 

[PristineSound]

You may be confused, we are talking about online UPS, the one that does double conversion, meaning from AC to DC then DC back to AC. The DC back to AC on commercial double conversion UPS uses PWM and the output is true sinusoidal.

Moreover PWM has nothing to do with the ability to create sinusoidal waves or not. Class D amps uses PWM.

 

[ElJaimito]

Definitely not better, research the types of ups, that one is cheap crap.

My IT company supplied Cyberpower UPS as standard for server installations for about ten years after having endless issues with APC. The performance for the price was excellent, and unlike APC, their bottom line did not seem to depend on burning out lead-acid batteries. We only had one faulty out of quite a lot sold, and that was rapidly dealt with by the company. We also used Eaton, but they stopped manufacturing UPSs at reasonable prices. Now we only sold high spec ones, but I have myself a 650VA line interactive Cyberpower as well as the online 2500VA Cyberpower my sound studio runs on, and I have had no issues. Main unit on its second set of batteries now. To be clear: IOE APC UPSs served their purpose well - data protection - but the battery life IOE was appalling and we had a high rate of DOA and warranty issues. The output waveforms were brutal in the 650 VA series. This is of course just one data point (though involving ~100+ units)

As far as the review is concerned, I agree that an online UPS would do the same thing more economically -- and that's what I have done. I live deep in the Spanish countryside, and at the end of a long supply line, so throughout the day we get voltage drops, and the boost function of the UPS running my studio operates multiple times a day. The UPS is also essential due to fairly frequent (though brief, seconds) outages, it was not so useful of course with the 19 hour failure we had recently! So, I have:

- Cyberpower online 2500VA on the recording studio
- Cyberpower line interactive 650VA on the Starlink (no fibre here) and POE switch for wifi
- Eaton online 650VA on my wife's computer
- Emerson Liebert online 650VA on the networking and server closet

They all earn their keep. The online UPS output seems pretty clean and does not cause any audio issues in the studio - though I haven't scoped it.

 

[kklarqvist]

If this re-generator unit was designed for Europe why is the output 60Hz? Most places in Europe use 50Hz mains. 10Hz offset between input and output frequency seems like a bad idea for audio. Assuming it is actually regenerating the AC by electronic means. It was tested in the US using '240V 60Hz ' input but for a re-generator targeted for Europe I would expect the output of 240V 50Hz. --- I assume it is not a synchronous motor, balance wheel, and generator inside the box.

 

[kyuu]

If this re-generator unit was designed for Europe why is the output 60Hz?

It's rated for both 50 and 60Hz. Amir fed it 60Hz, so it output 60Hz. Presumably if you feed it 50Hz, it will output 50Hz.

 

[kklarqvist]

View attachment 454153

It's rated for both 50 and 60Hz. Amir fed it 60Hz, so it output 60Hz. Presumably if you feed it 50Hz, it will output 50Hz.

Why would I assume that if I fed it 60Hz it would output 60Hz — it is a re-generator, I would assume it to generate the correct waveform for the application.

My comment was based on my assumptions on how the re-generator is functioning, I was not expecting it to lock to the mains frequency, but to synthesize AC using a more stable oscillator, with less phase noise, than the input signal.

The primary function may not be to reduce mains noise and distortion. Another function which was not explicitly reported (or measured) would be to reduce the "wall plug" impedance.

 

[Cbdb2]

Another function which was not explicitly reported (or measured) would be to reduce the "wall plug" impedance.

Which does what for your audio? Nothing except increase your amplifier peak output before clipping by .2db. If thats an advantage for you, you have bigger problems.

 

[amirm]

The primary function may not be to reduce mains noise and distortion.

The designer explicitly told me to test for this.

 

[elberoth]

Here are some pics of an older 2000i model I took a while back:

Under the floor, there are 6 SLA 12V batteries like this one:

https://www.amazon.com/dp/B06ZZ54QJB

There is nothing "audiophile" in the design of this unit - just a generic battery charger and inverter.

For what it is worth - I though it improved the sound of a Krell integrated, esp. when you went completely off grid (depending on the components you have , you could run from batteries for 1-2h). Later, I found out, that putting a AC mains filter improved it even further - which makes sense if you condiser the HF spikes it produces.

 

[a.dent]

I'm a bit late to the party but I bought one of these about 10 years ago when I had a buzzing transformer in a (very) expensive Danish integrated amplifier. When I complained about the buzzing the dealer took it back but claimed he couldn't replicate the fault. He blamed DC on my home power!

I naively accepted the amp back and bought one of these to clean up the power. (from the same dealer)
It worked to reduce the buzzing considerably but it had noisy fans so I replaced one background noise for another.

I changed the fans for much quieter ones, which solved the fan noise but of course negated any warranty. Within a year the Pure Power unit overheated and stopped working.

I sold the amp and the (repaired) Pure Power and bought a Japanese amplifier that is completely silent even at full volume.

So it seemed to clean up the power and make an audible difference.

I'm not sure if the latest versions have fans but if they do they will annoy you!

 

[michaelahess]

I actually searched for an online type, so I thought this would be. but it is not, correct.
I was misled by an algo. but your example has 3.5 stars

it is also not cheap crap. not everybody needs an online type. I don't need my sine-wave to be perfect.

Agreed 100%, but believe me, I do data centers, this is a good "low end" device.

I use cheaper line interactive liebert ups', with solar/battery ess, and my Cybertruck as backup to that. Much clear power, many great sound.