Northstar Generators

[elm_tx]

HeyY'all

I was leaning real hard towards the Honda generators when I walked into Northern Tool & Equipment. They had a couple of token Hondas on the shelf, and a whole bunch of their own brand, the Northstar powered by Honda Engines. They are noticeably less expensive then the Honda models.

Of course the salesman said they were every bit as reliable and quiet as the Honda, just less expensive cause I wasn't paying for the Name. This may be true, I don't know. I've never even started a generator, much less owned any.

Anyone out there have experience with this line of generators or suggestions of things I should be checking for. If it helps, my 5er can hook to either 50amp or 30amp service.

Thanks
Eddie

 

[Gary RV_Wizard]

The ultra-quiet Hondas are the inverter models, e.g. the eu1000i & eu2000i.  They generate DC power and then convert it to 120 VAC via an inverter. That process is much quieter than any mechanical AC generator.  So, maybe the Northstars with a Honda engine are as quiet as a Honda with a Honda mechanical output stage (but I'm skeptical of that), but they won't hold a candle to Honda (or Yamaha) with an electronic inverter for the output stage.  Look for inverter models and then compare their sound (dB) ratings.  When you do so, make sure the dB ratings claimed are all at the same distance SOund decreases with distance from the source, so you have to compare ratings at the same distance.

 

[King]

Right on, thanks Gary.
Art

 

[rotaryplow]

Sorry for being stupid and inquisitive!  Why are the standard Honda generators louder than the inverter models?  I thought the noise came from the engines and the big difference was the muffler design.
Marty: Lost in the world of portable power.

 

[John From Detroit]

Marty, that is an excelent question,  And I await the answer.

I can think of a few posibilities but the big thing I notice is inverter generators are about 2/3 the weight, I'm guessing this means that the motor is smaller for the same amount of power  And of course thus not as loud.

Part of that lighter weight has to do with the generator part, part with the flywheel in a regular generator you need a lot of rotating mass to provide that power SURGE when the air conditioner kicks in.  With an inverter model you can use lighter weight electronics to do the same job, though not always as well

 

[King]

Very likely the standard models have to turn at 3800 rpm in order to produce 60 Hz.  The inverter units can vary the rpm as the load varies, and probably run above 6000 rpm under most conditions.  The effect, soundwise, is like having more cylinders, the exhaust note is at a higher frequency, and is not as loud.
Art

 

[Jeff]

Very likely the standard models have to turn at 3800 rpm in order to produce 60 Hz.  The inverter units can vary the rpm as the load varies, and probably run above 6000 rpm under most conditions.  The effect, soundwise, is like having more cylinders, the exhaust note is at a higher frequency, and is not as loud.
Art

I don't know about the Honda but the Onan diesel runs much slower under normal loads than the AC constant RPM models.

 

[Ned]

The diesel models will run at lower RPMs than the gas units.  I would expect the gas engines to run at much higher RPMs.  The Honda EU2000i, for example, runs at 4300-5000 RPM, while the Onan QD products run at a max of 3600 RPM at full power.  The QD5500 (non-interter) runs at 3000 RPM.

 

[Gary RV_Wizard]

Much of the objectionable noise from a genset comes from high speed vibration and the rotating generator (as opposed to the engine) is responsbile for much of it.  Th eelimination of that rotating generator stage is a major reason why the inverter models are so much quieter.  The other major advantage of an inverter typre genset is that the speed can be reduced when the load is less than full (the typical case). A rotating mechanical generator stage relies on the engine RPMS to produce the correct alternating current frequency (60 cycles) and those exact RPMS must be manitained at all times, whereas the inverter types produce the correct frequency electronically and are independent of engine RPMS. An inverter needs only a good 12V source to operate and a 12 VDC generator is a much simpler device than an AC one.

Vibration resulting from imperfectt balance is also a major source of engine noise. The extremely well-balanced Honda egines are quieter than most , but if you are comparing a Northstar with a Honda engine to a Honda genset, then we can probably assume the engine vibration is about equal. It's worth noting, however, that Honda makes many varieties of engines for different applications and some are quieter than others. An engine intended for a Honda residential-use generator may be more finely balanced than, say, a Honda engine intended for a lawn mower or a power winch. Same basic engine design, no doubt, but probably more finely machined parts and more care in assembly of parts with matching tolerances.

Surprisingly, exhaust noise is not so terribly objectionable as vibration noise, though it can indeed be loud. It doesn't whine and doesn't create harsh vibrations in the air that grate against the bones as well as the eardrums.

 

[Karl]

Art,

The owners manual says they run from 4,300 to 5,000 rpm depending on load, but I think it's more the lack of that massive, cast iron flywheel/cooling fan found on regular generators that makes them quieter.