Emergency Generators

Jeff H

NW Ohio
LOL! HF probably does. I've not thought to look because I didn't know there was such thing, but it makes sense. Last semester, I just got them started on variable frequency drives and we go through the whole "how do you get a different frequency, if the power company is supplying a set frequency??" Take the AC, turn it into DC, clean up the lumpy DC and then INVERT it - make it AC again. SINUSOIDAL AC to boot!

Never even thought to apply the concept to a portable generator. Given that even a DC generator produces AC, before it is mechanically rectified, using a commutator, I wonder if these new inverter generators bother with the commutator (wear items) to get the DC, or rectify the produced AC using solid-state? Probably use solid-state. This is cool. I have some research to do.

One thing about these smaller generators is that they'd be more portable. If I were forced to suddenly relocate - evacuate my home for some catastrophe of nature, chemical spill, whatever, I'd surely not try to lug my 5k generator along, but I'd at least think about grabbing a small one and dragging it along.
 

Petrol & Powder

Well-Known Member
Inverter generators make AC current, convert it to DC and then BACK to AC. The conversion is accomplished with solid state rectifiers and inverters. The type of final AC output depends on the sophistication of that final inverter. (Square wave, modified sine wave, sine wave). And of course, you pay for that final inverter type. Some are better than others, there’s no free lunch.

From an electronics point of view, all that electrical conversion is somewhat inefficient. Some energy is lost at each conversion. From a total efficiency viewpoint (amount of fuel burned per watt) the efficiency can be higher when operating under partial loads because the engine doesn’t have to be run at a constant speed to maintain the correct frequency.

The inverter can react quicker to maintain the desired frequency when the generator is exposed to sudden shifts in load as compared to using a purely mechanical governor to regulate the frequency via engine speed. However, a conventional AC generator (without the inverter) can produce “clean” (stable) output under constant load; and it can do it with a simpler overall system.

With an inverter generator you are paying for a lot of electrical components. This can be money well spent if the loads vary a lot or it can be an excessively complicated system to get the same results under a constant load. It all depends on your application.
 
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Bret4207

At the casting bench in the sky. RIP Bret.
I think the primary advantage of an inverter generator is the weight and the low noise. My 2kw Honda idles below the dB level of the human voice. It is also relatively light. Loading a big AC generator into my vehicle by myself for use at the track was not going to happen. This little gem is not weightless, but not a back breaker, either. The downside is they are expensive. MSRP for the Honda is around $1000.00.
I don't know what the MSRP is for a 2kw Honda Inverter Gen is now, but even the least expensive one I just found is $1300!!! Times, and costs, they are a changin'... You pay for quality.
 

Snakeoil

Well-Known Member
I don't know what the MSRP is for a 2kw Honda Inverter Gen is now, but even the least expensive one I just found is $1300!!! Times, and costs, they are a changin'... You pay for quality.
Yeah, I am not surprised. I bought that generator back in 2007.
 

Snakeoil

Well-Known Member
I have a 6.5kw Honda AC generator that I inherited. Great machine and runs like a watch. But it has wheels because you ain't moving it without the wheels. I have it at our camp because storms and outages are worse here than home. But the little Honda inverter is so handy, that I still use that in the barn rather than the big one which is sitting right there. No power in the barn so run my lathe and saws off the generator.
 
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Hawk

North Central Texas
I just checked on Amazon.
A Honda 7,000 inverter is $7,000, marked down to $4,999.99.
On the duramax 9,000 watt inverter is $2,500, no inverter is about $1,500.
 

Petrol & Powder

Well-Known Member
Honda engines are awesome and well proven. The engine half of that device is great. But paying a premium to get the other half of that device, the part that converts that rotating force into electricity,…I’m not sure that’s always absolutely needed.

There are applications in which the inverter generator setup is superior to a simple generator. The reduced rpm’s at partial load results in a quieter unit and reduced fuel consumption. Those are both big pluses.

The “clean power” marketing hype is a bit overblown. It really depends on how you are using that AC power. A light bulb doesn’t care about slight fluctuations in AC frequency. A lot of electric motors can tolerate small fluctuations in AC frequency as long as the input voltage remains adequate. A lot of electronics convert AC current back into DC current with lower voltages (like the charger attached to the laptop I’m using now). That charger can take 100-240 volts AC at 50 to 60 Hz and puts out 19.5 volts DC. So, the computer never sees the line voltage OR line frequency.

I’m not saying inverter generators are bad (they are actually pretty awesome) but I am saying we got by without them for a LONG time. Your application weighs heavily on what type of generator is best for you.
 

RicinYakima

High Steppes of Eastern Washington
Prices are about the same as when I bought mine. It is a 3500 watt Yamaha, electric and manual start that has always lived in the bed of my pickups since 2000. The previous Honda was stolen from the back during the Y2K scam and panic. Other than two batteries and oil changes it has been perfectly fine. It has only run the AC on the 5th wheel and "Bowman Power and Light" when dry camping with a group. Only twice have I run an extension cord to the house to keep the freezer and refer cold and run lights for a day. It probably has less than 350 hours in 22 years.