Aldi £59 petrol generator and television

Yep. Too bad it was incomplete. Generators have an irritating habit of producing distorted waveforms when loaded unevenly between phases. This is fairly common with generators that have two phases, 180 degrees apart, for outputs. Load one at 400VA and look at the waveform. It's fairly ugly.

The problem is that all switching supplies that actually comply with some governments conducted radiation standard has a 50/60 Hz low pass filter on the AC input. That's great for keeping the high frequency hash from radiating out the power line, but not so great when presented with an input waveform full of harmonics. It's not too horrible, but it is a consideration. For example, if the input to the switcher were a square wave, 1/3 of the power would be in the harmonics. That power has to go somewhere. Some is reflected, but most of it is dissipated in the input filter. At 400 VA, that's about

133 watts of smog.

With an unbalance load, most generators will have up to 5% of the power in harmonics. It's worse for small generators because the cores like to saturate at rated power output. At 400 VA (one phase), that's about 20 watts dissipated. Some switchers can handle it, others prefer to blow the input fuse, if there is an input fuse or breaker.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com               jeffl@cruzio.com
# http://www.LearnByDestroying.com               AE6KS

Jeff Liebermann wrote

Just like yours on how SMPSs fail was.

Irrelevant to the generator being discussed which can't do that.

But the generator being discussed doesn't.

And you don't get that with the generator being discussed.

You don't get that with the generator being discussed.

Not with the generator being discussed it isnt.

It isnt with the generator being discussed.

It isnt with the generator being discussed.

Not with the generator being discussed it doesn't.

Not with the generator being discussed it isnt.

Not with the generator being discussed it isnt.

Can't happen with the generator being discussed.

Not with the generator being discussed it doesn't.

Not with the generator being discussed it isnt.

Doesn't happen with the generator being discussed driving the TV being discussed.

Don't waste your time with this troll.

An unbalanced load isn't required, which only creates even order (asymmetric) distortion. A single phase generator will happily create odd order (symmetrical) distortion without an unbalanced generator load. For example:

Scroll down to the oscilloscope photograph. Note the noise and distortion. This is fairly typical of cheapo small geneators with mechanical regulators. I've seen worse.

Speaking of worse, not the oscilloscope photos:

It's this garbage waveform that causes switching power supplies to complain and UPS power supplies to refuse to run on generator power.

Incidentally, if you plan to look at the waveforms produced by a gasoline generator with an oscillosope, use two scope probes and differential inputs. One probe connects to each side of the power line. The two probe grounds go to the generator frame ground. The scope input selector is set to A-B. That will remove any common mode noise on the display, and provide some protection against accidentally getting the oscilloscope case at line potential.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Jeff Liebermann wrote

But you don't get anything like the amount of distortion you were going on about, so it isnt a problem with an SMPS being powered from that particular generator being discussed.

No SMPS will have a problem with that.

You don't know that the generator being discussed is anything like that.

You don't know that the generator being discussed will produce that result.

One of those wasn't even being discussed.

No news to me.

[not much]

Why are your posts so content-free?

-- Tim

"That excessive bail ought not to be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted" -- Bill of Rights 1689

empty vessels....

-- To people who know nothing, anything is possible. To people who know too much, it is a sad fact that they know how little is really possible - and how hard it is to achieve it.

The oscilloscope photos in the URL's mentioned show the output waveforms with and without loads. As I indicated, and you apparently missed, it is NOT necessary to have an unbalanced load on the generator in order to produce a distorted waveform. Also, it's a fair assumption that this 800 watt generator is going to be powering more than one device while camping. Besides the TV, there might be some lamps, a laptop charger, satellite TV receiver, smartphone charger, inkjet printer, and all the conveniences of portable modern living. In general, the generator waveforms become more distorted with increased load.

As I previously suggested, some substantiation would be helpful. If you had impeccable credentials, were a recognized authority, had previously demonstrated expertise in this area, and perhaps were a Nobel Prize recipient, I might accept your unsubstantiated judgments without question. However, lacking those requirements, and being apparently only able to produce one-line erroneous statements of negligible value, you do not qualify. Please explain why numerous articles on generator to UPS compatibility should be ignored.

In the past odd 20 years, I've run emergency generator versus switching power supply problems many times. My favorite was while working with computahs at a medical billing office. Someone dragged in a Genrac 8kw(?) generator and wired it to a transfer box. It was a professionally done installation by a licensed electrician. I stupidly suggested we do a dry run with the building on full power, and was immediately assigned the task. The day arrived, the big switch was thrown, the generator started immediately, and about 30 assorted UPS backup power supplies beeped a few times, and shut down in self defense. That powered down all the servers and network hardware, which effectively shut down the network.

On the APC SmartUPS line (as opposed to the BackUPS line), there is a switch to reduce the sensitivity to input waveform distortion. We went around flipping switches and rebooting servers (after a 30 minutes file system check). When everything was back up and running, the power was again switched off, and again all the UPS's shut down.

I drove to my palatial office and back with an oscilloscope to look at the waveform. Even without a load, it looked something like this:

When I added all the non-computer loads to the Genrac generator, the waveform became asymmetrical, because the load was not balanced between the two phases. My clamp-on ammeter showed about 10A on one leg and 7A on the other. It didn't take much to cause problems.

After about 8 power fail simulations, we were never able to bring everything back up gracefully on generator power. It wasn't just the UPS's that were having issues. The DVR for the security camera systems refused to run. The wall warts for powering some Netgear switches blew up and had to be replaced. Several CRT monitors acted strangely and refused to produce a stable display. The Lucent phone system would go into protection mode intermittently.

After the exercise was over, I elected to restore two of the servers from backup tapes, because I didn't want to take the chance that all the power thrashing had caused any data corruption. That took most of the night. When business resumed on Monday, it was soon discovered that the one server that I did NOT restore, had some minor data corruption.

There was no way the office was going to run on this 6kw(?) generator. The generator was removed, permits arranged, and a rather monstrous and expensive 25kw diesel generator was installed. Attached to the power leads was a large box full of low pass filter components to remove spikes. I didn't need to look at the waveforms as it ran the various UPS devices and switching power supplies perfectly.

You don't know what I know.

True. You haven't learned anything. I judge people by their willingness and abilities to learn. You fail both criteria.

A while ago, I attempted to classify various usenet personality types.

At the time, I hadn't even considered a classification suitable for your style. You post useless and erroneous comments, and then wait for those with some understanding of the topic to correct your misinformation. The more attention you attract, the more useless comments you produce, resulting in a positive feedback mechanism. I suspect that your primary purpose is to attract corrective attention, rather than answer the questions or debate the validity of the proposed explanations. Had you demonstrated some understanding of the topic by asking some intelligent questions, I might consider continuing, but as it stands, I have no interest in entertaining you or cleaning up your mess. Good day.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Er Jeff, this is Rod Speed, ultimate Internet idiot par excellence you are addressing.

Don't waste our bandwidth,.

--
To people who know nothing, anything is possible.
To people who know too much, it is a sad fact
that they know how little is really possible -
and how hard it is to achieve it.

Jeff Liebermann wrote

Yes, but you don't in fact get anything like the distortion that you were going on about with unbalanced loads on

2 phase generators which aren't even relevant to the particular generator and load being discussed.

Didn't miss anything. The distortion actually seen with the particular generator and load being discussed is nothing like enough to be a problem with a well designed SMPS.

Yes, but that's not necessarily much of a load.

None of which are much of a load.

Duh. But even with all of those you listed, it won't be a problem for a well designed SMPS.

You didn't provide any of that yourself until I rubbed your nose in the fact that you never provided any yourself on your claim about how SMPSs fail.

You in spades with your claim about how SMPSs fail.

Because we arent discussing UPSs, we are discussing TVs instead.

Completely and utterly irrelevant to what was being discussed, that PARTICULAR generator mentioned in the subject and a TV.

Completely and utterly irrelevant to what was being discussed, that PARTICULAR generator mentioned in the subject and a TV.

All completely and utterly irrelevant to what was being discussed, that PARTICULAR generator mentioned in the subject and a TV.

I do know that you were rabbiting on about two phase generators and UPSs that have NOTHING to do with what the OP asked about.

Yep, none of the irrelevant shit you posted is any news to me.

No one give a flying red f*ck how you stupidly 'judge' people.

Particularly when you keep raving on about about situations that have NOTHING to do with what was actually being discussed.

Everyone can see for themselves that you are lying.

Alas you are wasting effort arguing with woddles - the most clue resistant poster uk.d-i-y has known...

While the evidence would suggest otherwise, logic suggests that he can't actually be totally stupid, because to be so consistently wrong on every single one of the many topics he is willing to submit his opinion, must actually take some considerable effort. Most clueless twonks actually get the right answer by accident sometimes.

--
Cheers,

John.

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|        John Rumm - john(at)internode(dot)co(dot)uk              |
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I can't imagine a 2 stroke aldi generator would even last long enough to destroy any electronics. the thing must last about 2-3 minutes tops before seizing, assuming it even starts out of the box.

That'll be why they give a three year warranty? Instant money back - provided you have the receipt. Wish others did as well.

--
*If only you'd use your powers for good instead of evil.

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

it could be a 100 year warranty. There's no way such a generator isn't complete trash and won't have the endurance of a birthday cake candle.

We have a local iced cream truck that rides around through the park at various parts of the day. It has one of those hanging on the back, operating the freezer I presume. It seems to work for them just fine, sounds funny though ;)

Jamie

That one tells jokes? I'll get me coat.

I can't vouch for their 2 stroke model but I do own an Aldi 4 stroke generator that has served me well for 8 years. It doesn't come out often but when it does it performs faultlessly. It powers everything in the house (not all at the same time) during power outages, runs power tools away from the mains, and lighting and PA equipment at an annual outdoor event. The longest daily use was 7 years ago when we had no power for 5 days, it ran approx. 18 hours a day every day.

Mike

I dunno anything about the Aldi one but several years ago I bought a cheap 2 stroke, 800w, made-in-china one from Menards for $100 or less and it's still working fine.

We had a nasty ice storm, lost power and after the house dropped to 60, it was either do something or find a hotel.

It chugged along for hours sitting outside in 20F degree temps, we have hot water gas heat so it only needed to run the circulation pump. Just did a quick mod to the electrical on the furnace and ran a heavy guage cord thru a drilled hole in the wall.

Since then I've used it several times, usually starts on the 3rd or 4th pull, even after sitting a year or more, stale gas and everything that goes with it.

Don't get me wrong, contruction wise it's a peice of crap but seems to be hanging in there just fine.

If I lived in an area that has regular outages, this thing wouldn't be in my top 10 list (or top 100) but for the occasional use and price, it's just not as bad as you think.

-bruce snipped-for-privacy@ripco.com

So you lack a grasp of reality. Reliable 2 cycle engines are quite common - they have been used in chain saws, outboard motors, and a variety of other uses for more than half a century. The chief cause of premature failure is some idiot (look in to a mirror for an example) failing to properly mix the oil and gas.

The generator (actually an alternator) is also trivial. By incorporating a small permanent magnet into the rotor it would be trivial to build a self-energizing alternator; output voltage regulation would be done by stepping the output voltage down, rectifying it, and varying the current to the rotor windings, just as is done in an automotive alternator. That output voltage should be quite stable.

Admitedly, frequency regulation would be poor. They probably use an air vane governor for speed regulation.

As far as the original question, I wouldn't suggest anyone try to use one for any application the manufacturer says is unsuitable. But I would be more concerned about the unstable frequency than the output voltage. I've seen many LCD monitors whose power supply is rated for input voltages ranging from 90 to 275 volts AC at 50 - 60 Hz.

PlainBill