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The Little Generator that could – Part Deux

Cheap ChiCom GeneratorIn response to my first article [1] about little generators, specifically the little $100 ChiCom Special, Mike Hendrix asked the following

When I plugged my motorhome in to it I notice that my circuit tester says the Neutral & hot wires are crossed.

Do you think I should disassemble and switch the connections on the output plug?

The outlet tester being a little gadget that you plug into an outlet and that indicates correct wiring on a series of 3 or more neon lights or LEDs. Normally Mike’s concern is serious, as it could lead to shocks and will often make GFIs trip on apparent neutral faults.

With a generator, things are a little different. There are two leads coming out of a generator. Either one can be designated as hot and the other neutral, the neutral being connected to earth ground, or they can be allowed to float. In the case of floating leads, neither lead is hot nor neutral because those terms are ground-referenced.

Between the time I posted the last article and this one, I had a friend pick up the last two $99 specials that the Chattanooga Northern Tool store had in stock. I figured that I could sell my old ones for more than I paid for the new ones when the power goes out up here. Turns out that I was a visionary :-) I sold my red one to some camper/rafters who had not come prepared for dry or primitive camping. They had a heater (yep, more than 1000 watts) but no generator, thinking they could pitch a tent in the RV park and plug in. The park is closed this time of year and besides, they don’t rent short term like that. I fixed them right up for a mere $120.

So I have a couple of brandy new generators on my hands, though probably not for long. I decided to open one up and see what was under the hood and answer Mike’s question at the same time. I was very pleased to discover that they’ve made several improvements in the unit over the ones that I bought a couple of years ago. Most significantly, they’ve fixed the choke problem.

New Gen 01 [2]First to Mike’s question. This is the back side of the front panel of the generator. Several items are identified including the voltage regulator capacitor, the outlet and the two leads coming from the generator. If you look closely at the outlet, you’ll see that neither of the other wires are connected to the green ground wire. The output is floating. This is further confirmed by the megger, the display of which is visible in the lower left. It is saying that the resistance between the output (red clip) and ground is >1.999 Gigaohm at 500 volts. Damn fine insulation, rarely seen in rotating machinery.

So Mike, the answer is NO, you don’t need to rewire anything. If you don’t like a floating system, you could select one wire, say, the one that connects to the wide slot on the outlet (red wire in this photo) and tie it to the green wire to make a neutral. I personally would not. This increases the shock potential over a purely floating system. See my comments on the first article for more details.

New Gen 02 [3]While I had the unit open, I decided to photograph and describe some other features. Several things stand out. One, the simplicity of the governor and the attention to its details. Note the small spring labeled “anti-surge spring”. This spring takes up the slop in the linkage. While not an issue initially, as the linkage wears, the increased slop can cause surging. That little spring handles the situation nicely.

On a negative note, notice the loose connection on the black wire at the upper left. I sure am glad that I took this unit apart, for that is part of the ignition circuit and would have driven me crazy trying to start a generator with no spark!

New Gen 03 [4] This photograph shows a small but nice detail. A genuine metal Japanese-style fuel cock with a reserve position and sediment bowl. Beats the heck out of the plastic valve that “brand names” like Generac use.

New Gen 04 [5] This photo shows the new and improved carburetor. Obvious in this photo is the fact that the choke now closes completely on its own. This will fix the hard cold starting problem that these generators are notorious for.

Also note the drain screw, something missing on generators costing vastly more. This screw lets you drain the last remnants of gasoline from the bowl before you store the generator.

And if you forget? That single nut makes removing the bowl for cleaning a snap. The bowl can be removed without removing the carb or the front panel. Nice.

New Gen 05 [6]This shot is looking in through the generator vent holes. Notable here is that the windings are copper. Many cheap (but much more expensive) generators have aluminum windings to save money since copper costs so much more than aluminum. This little $100 jewel has genuine copper in its windings. Also note the quality of the aluminum injection casting. That’s Japanese-quality work.

New Gen 06 [7]In this shot, the camera lens is positioned up against one of those slots and is looking at the rotor. Several things are apparent. First, copper windings again. Second, the whole affair has been dipped in varnish and baked, a standard treatment for industrial motors and generators but extremely rare on portable generators.

The varnish hardens during the bake to form a solid mass that is practically impervious to water, oil, dirt and other gunk. Even I was surprised to see that level of quality on this unit.

New Gen 07 [8]This not-very-good photo is a close-up of the carburetor mounting surface. I took this photograph to demonstrate the quality of machining. The lighting and smear of gasket sealer doesn’t do it justice. The finish is almost mirror-like, with only the slightest feel of grooves apparent to the fingernail. In my experience with CNC machining, this level of finish is usually only seen when either diamond or ceramic bits are used and the machine is tighter than Dick’s hatband. Remarkable for a unit this inexpensive.

New Gen 08 [9]Here is another photo showing quality details. What you see is the stator “iron”, actually a sophisticated silicone steel. It is made up of stacks of thin stampings called laminations. The laminations are insulated from each other and prevent eddy currents from flowing in the iron, creating heat and inefficiency.

All else being equal, the thinner the laminations, the better. These are extremely thin. The laminations in my high dollar Generac generator are twice as thick. It costs more to stamp that many thin laminations but it contributes to a more efficient generator. Again, I’m shocked and amazed to see this in a $100 generator.

New Gen 09 [10]This last photo addresses something that started a tempest in a teapot in the Usenet RV group. Noise. Most of the noise from a 2-stroke comes from the intake. This is a reed-valve-type engine. The reed valve allows air to flow into the engine from the carburetor but prevents its reverse flow. When the thin reeds slam shut, they make a loud pop. 3600 times a minute on this machine.

The only complaint that I had with the old unit was that at full load, the intake roar was about the only sound heard. While not loud like a construction generator, it was louder than I’d have liked.

I guess those crafty little ChiComs thought so too, because they’ve put physics to work neutralizing the roar. Specifically, the’ve redesigned the air intake to form a Helmholtz resonator (yeah, I know I mis-spelled it in the photo. The software I was using would not “undo” and I didn’t feel like starting over again.) This resonator is tuned to the frequency of the intake roar and creates a sound wave of the same amplitude but of opposite polarity from the one coming from the engine. The result is that they cancel each other.

This unit is significantly quieter than my previous one. I can’t find my decibel meter so I can’t quantify the difference but it is significant. Further contributing to the reduction in noise is the use of a sound-deadening plastic compound and the heavy reinforcing of the cover which dampens resonances before they can happen.

To summarize, I’m even more impressed with this generator than I was before. The incremental improvements just add to the inherent quality. Oh, and for the certain individual who claimed that he would not buy one because he “probably” could not get spare parts for it, the manual is 25 pages long, 10 of which are exploded diagrams and part number call-outs. The company that imports these things had a website [11] and can be contacted toll-free at 888-908-6200.  Personally, I can’t imagine spending any time repairing a $100 generator but hey, others are different.

So, while you can’t buy a set of piston rings for a $600 Honda EU1000i, you CAN buy a set (or any other part) for this $100 ChiCom special. Hmmmm.

Speaking of inverter generators, if you simply MUST have an inverter generator, the same company has one for you.  Here [12]. Amazon [13] has it for $300 and free shipping.

Wait, oh heck, what is that?  I think my debit card may be chewing its way out of my wallet.  Oh noooooooooo……..