inverter generators

This is the manual for the Yamaha EF1000:

df

The schematic at the end shows two three-phase permanent magnet alternators (1,2) which presumably are rectified to DC and then inverted to 60Hz AC. I haven't worked on one of these generators but motorcycles use those alternators.

I would guess that one of the alternators must put out enough voltage at idle, the other is more efficient at high speed. The stepping motor (21) might control the throttle. The bottom part of the schematic is the engine ignition.

jsw

I'm not sure on what exactly goes on inside them, but the idea is that you can maintain a stable output frequency over a range of engine speeds.

with a normal genset, you must run the engine at a fixed speed, even if there's no load which wastes fuel.

Also, an alternator running at higher speeds can be smaller than one running slower.

This is the manual for the Yamaha EF1000:

The schematic at the end shows two three-phase permanent magnet alternators (1,2) which presumably are rectified to DC and then inverted to 60Hz AC. I haven't worked on one of these generators but motorcycles use those alternators.

I would guess that one of the alternators must put out enough voltage at idle, the other is more efficient at high speed. The stepping motor (21) might control the throttle. The bottom part of the schematic is the engine ignition.

jsw Thanks for the schematic, although I didn't get an answer. Item #5 the control unit could have rectifiers and an inverter on it, but I suspect it just as it is labeled, control unit- it controls the engine speed depending on load. Thanks, Mike

"amdx" wrote in news:7e429$4c20a4ff$18ec6dd7$4746 @KNOLOGY.NET:

Here is the EU2000 diagram

with a paragraph at the bottom: Operating Principles describes what's going on in there.

This may help:

h

Ok that tells me what's going on. I didn't pay attention at the time but the Yamaha schematic Jim linked to was not an inverter generator. z, your Honda link is an inverter generator and does rectify AC to power an inverter. Thanks for confirming my hunch, Mike

I'm late to the thread but:

Yes! an inverter generator makes DC then 'inverts' it to AC. I would expect that most use a 3-phase or more brushless AC generator, which is rectified and inverted to 120V, 60Hz (or whatever, depending on where it's sold).

The nice things about them are that they are versatile for the manufacturer, and they save gas.

The not-nice thing about them is that inverters burn up because of peak loads, where old-style generators burnt up because of long-term loads. So an inverter generator, unless designed with more inverter than necessary to meet the advertised specification, will just click off (or fry) on overload, instead of gracefully sagging.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

Anyone know why someone chose to call this sort of device an "inverter" ? This seems counter-intuitive and has always puzzled me.

I tend to agree with the final result of the answer -- even for running "fancy electronics," a regular generator is generally just fine -- but I really have to wonder how much of an "expert" he is when he says things like:

"The best power comes from a plain and simple generator. This is where commercial power comes from, a rotating magnetic field in a coil that generates a nice pure sine wave. Not sure why you seem to imply that electronics need something else - this is what they get out of a wall socket, what they are all designed for. I don't know why you need gfci or surge protectors, a home generator is pretty safe from transients that can come off the power lines from faults, lightning bolts, etc."

Sheesh! How about:

-- The stuff coming out of the wall is much more stable both in voltage and frequency than that coming out of a generator

-- GFCIs are meant to protect people, not generators or connected electronic devices

Also, he should replace "hard" in this sentence:

"Most cheap inverters suck, because it's really hard to synthesize a good sine wave, so they cheat and make squarish waves."

...with just "more expensive."

And I'd like him to find me the transformer in a ceiling fan ... or find a PC that doesn't use a "power transformer" in its power supply:

"If you have equipment that can deal with these pseudo-sine waves, that's the way to go as they are very efficient. Most electronics have no problem with this, as they take the line and make it into DC right away anyway. Like a compact fluorescent bulb, or a PC. But some appliances have a problem with this, in particular anything with a power transformer in it, like an older microwave oven or stereo amp or fluorescent tube fixture or ceiling fan."

I suppose I'm just being picky though. These days "experts" seems to mean "isn't *completely* ignorant on the subject," and its clear he does know at least a little more than the average bear on the subject.

---Joel

A "normal" power supply converts AC to DC, so an "inverted" power supply converts DC to AC?

That's what I always guessed...

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Mike

Look at the top of page 21, "...the inverter control unit..."

jsw

... or on the product page

"Inverter System with Pulse Width Modulation - Industry-leading system produces higher-quality and cleaner electricity. Results in pure sine wave as clean or cleaner than commercial power and can operate products with built in microcomputers", or at its name, "Inverter EF1000iS".

Wayne

I suppose that happens occasionally, but in practice they are made with protective circuitry. I loaned out my EU-2000 to my father who promptly connected it to a shorted out cord. (Much to my consternation, because I had heard that same story)

All that happened was the thing stopped putting out power until reset and restarted. Then all was well.

Vaughn

Look at the top of page 21, "...the inverter control unit.

Sorry, I'm not finding that, either on the page labeled 21 or on pdf page

1. Any help?? Mike

find

that's

problem

anyway.

it,

or

Transformer, as in, line voltage goes to a winding around a core. SMPS = don't have a transformer at the input, they have a bunch of stuff = inbetween. Physically, motors are just as transformery as transformers, = though it's certainly a misnomer to be calling them such!

Someone should make incredibly cheap VFDs suitable for running shaded = pole type motors and legacy transformerized equipment, then convert the = entire house to DC. Way better power factor for all those SMPS's...

...Of course, then your 120/240V switchable supplies all croak, which is = still most computers.

Tim

--=20 Deep Friar: a very philosophical monk. Website:

Hey Guys, Just a NOTE here: ALL Electrical Generators produce their power in AC, PERIOD. What you think of as DC Generators have Commutators that convert the AC from the windings, mechanically to DC, coming off the Commutator Brushes. In the Inverter/Generator case, the Main Genend Windings, are 3 Phase AC that is rectified, to DC and then feed into the DC input of the Main 60 Hz Inverter. If the load Power is more than the DC Input to the Inverter Section then the CPU Controller ramps up the Throttle on the Engine to provide the required Power for the load. this way the engine only provides just enough power to satisfy the load on the output of the inverter, thus saving fuel, and machinery wear. Great concept but give me a nice old Diesel 1800 RPM Genset any day.

--
Bruce in alaska
add  after  to reply

have a transformer at the input, they have a bunch of stuff inbetween. Physically, motors are just as transformery as transformers, though it's certainly a misnomer to be calling them such!

motors and legacy transformerized equipment, then convert the entire house to DC. Way better power factor for all those SMPS's...

most computers.

Hm... I havn't bought one with a switch for quite a while.

Maybe most (all?) of the ones with active PFC are universal input?

pg 8 - "economy control switch" section explains variable rpm while loaded, the hallmark of an inverter equipped generator.

Wayne

Sure, sure... but if you take a look at the bill of materials for a PC's power supply, a "transformer" will definitely be included, whereas for the ceiling fan you'll only see "motor." If someone on a web site claims to be an "expert," I would think they'd be using terms as they're commonly used.

Perhaps the one about PC power supplies is splitting hairs. I suppose the way to write the response is to talk about, "directly line-connected transformers -- 120V, 60Hz in the U.S. --" or somesuch, but perhaps that isn't any more useful to the average reader than "power transformer." OK, I admit it, maybe the average person doesn't consider their PC power supply as containing a power transformer...

"Someone should make incredibly cheap VFDs suitable for running shaded pole type motors and legacy transformerized equipment, then convert the entire house to DC. Way better power factor for all those SMPS's..."

I kinda liked the idea of running the entire house off of 3 phase, 400Hz power...

"...Of course, then your 120/240V switchable supplies all croak, which is still most computers."

Many such supplies will work off of high-voltage DC directly, I'm told.

---Joel