Utterpower PMG Pre Testing and trouble shooting guide 

After many years of working as a Technician and Trouble Shooter, I've learned that there is no substitute for verifying the basic wiring in your generator, not doing so can lead to a lot of wasted time, and even permanent damage to your machine, why not take a moment to verify the wiring and the connections? you might ask, what is typically found?

Answer: Regardless of design or manufacture, errors are found; sometimes an assembler will miss label a lead or lay it down on the wrong terminal, this is very easily discovered and corrected if you follow the simple steps that follow. 

But just as important, you will learn the fundamentals of your generator and you will be in a far better position to reconfigure the generator for alternative uses, change from 120/240 to 120 VAC only, and trouble shoot this KISS1 engineered machine.      

 If you can figure out a flash light and get the polarity of the batteries right, you can trouble shoot and properly hook up the PMG. Warning! All tests are to be conducted with no leads connected, and the PMG at rest, not connected to any prime mover.

There are many differences between AC and DC power, but there are polarity issues in AC just as there is in DC power. To demonstrate a more clear understanding of polarity, we'll discuss the two windings, why we have two of them, and just how similar they are to the two flash light batteries we have in a typical flash light we all grew up with. To start out, just how many of you have put in one battery backwards and were totally stumped when you turned it on, and the light bulb didn't light? If you were like the majority of us, first thing you did was check to make sure the batteries plus and minus (polarity) were in the same direction. We have the identical issue here, and there's little more you need to understand to get it right.

Figure 1  This is the complete wiring diagram of the Utterpower PMG 60hz version

All you need to keep in mind is that assuming anything in the electrical world is right out of the box will eventually make you look like a fool, or far worse! I know people  who have wasted a complete day, and others who burned up expensive equipment because they were in a big hurry, and couldn't take the 2 minutes to VERIFY the wiring.

Figure 2  Here's the image you need to store in your mind for quick trouble shooting

Figure 3  wired for 120/240 VAC operation

Look at the flash light batteries above, if you place your volt meter across terminals 1 and 2, expect to see around 1.2 volts from your nickel metal hydrate battery cell. Now let's move our test leads to 2-3 and 4, again we see 1.2 volts. Now move your leads to 1 and 4, you should see 2.40 volts or the sum of the two batteries.

Figure 4 a most typical wiring ERROR

I've simply lost count of how many times I've received email on this wiring error in many brands of generators, many have two stator windings exactly as this one does. The difference with the PMG is this is all the electrics there is, get this right, and you got it all. 

The trouble Report is:  "I have good voltage between 1 and 2, and I have good readings between 3 and 4, but between 1 and 4; I see zero volts. Yes, you noticed in the above figure, that one battery is in backwards, and the two batteries are opposing each other instead of working together to give us our higher voltage, but individually, they're doing their job.  Note that all loads placed across 1 to 2 and/or across 3 to 4 will still see the expected voltage. This is exactly the case with the AC voltages, and if we move the decimal two places, the voltage readings you will see between NMH batteries and the 60hz AC voltages will be similiar. 

Now may be a good time to point out just how simple it is to get it right with the PMG, if you try turning the shaft on a new PMG, you will feel seal drag, and a little cogging, but you can 'snap' the shaft around with your wrist and make some measurable power. Put a strap across 1 to 2 and try it again. It's like the shaft is frozen, you have put a short across the winding and the generator makes good power even at a few revolutions per minute. Move to 3 to 4 and try the same thing.

To assure you have the winding working together, simply place a 12 volt auto tail light or dome light across 1 and 4 and assure that 2 and 3 are strapped together, a quick snap of the wrist will light up that bulb brightly. So what will you do if it doesn't light up?

Answer: You will verify the bulb is good by putting it across a car battery, you will recheck and prove the strap is good at 2 to 3, you will verify all test leads are good! Hint, the bulb will light across 1-2 or 2-3 as well, only not as bright. Only after you verify these things will you swap the wires coming out of the generator head and onto the terminal strip at positions 3 and 4 for instance, and then retest.. (just like turning around the flash light battery in your flash light to make them work together.

120 Volt Only Operation.

If you have no 240 VAC loads, you will nearly always wire the generator for 120 VAC only operation, the advantages are an evenly loaded stator, and all of the generator capacity can be directed into one load. Trouble shooting wiring errors can be typically done without a meter.

Figure 5.  Utterpower PMG wired for 120 VAC only

In the above figure, we see the two coils in parallel, in our analogy, this is no different than putting two flash light batteries in parallel, they don't make the higher voltage as when they were wired in series, but they do work together to provide twice the current as either one could do alone. If you get one of the coils wired in backwards, they will oppose each other and you will not be able to turn the shaft by hand! How easy is that to figure ? I doubt we need to draw you a picture of two batteries in parallel with one battery reversed, you'll likely know the batteries will be opposing each other, this time current flows, and in no time the batteries will be too hot to touch, and dead shortly.

The PMG is just that easy to sort out, but that doesn't mean there are not other relevant tests that you can and should perform. I highly suggest you look at the following in addition and write down your findings.

Use a Megger or the meg ohm scale on your VOM to measure between the windings, example, between lead one and four with no connections made elsewhere, you should see an infinite reading or real close to it. We expect the same results between either winding and the generator case ground.

Another measurement you want is to take an initial reading of the two windings with an ohm meter and write down what they looked like initially, this is valuable information for trouble shooting in the future. Also note, this is where the cheap meters can fail you, a VTVM, or a quality ohm meter is often needed to read low resistance windings with any accuracy.

If you read this short article and you understand it, you are far ahead of the pack, if you move the decimal point over two from the battery analogy to the AC voltages you expect, you'll be in the ball park at 60HZ.

It's a fact that those who sell Generators often know nothing about them, so it's very important that you build your own knowledge base and you independence as well.  The beauty of the Utterpower PMG is it is brutally simple, easy to sort, and works when others have long given up. Unlike some of the PMGs before it, the engineering problems have been addressed, and the many improvements;  cool running and the elimination of contamination problems to mention two have been patented.

I hope this short article has given you some insight into the simplicity of the PMG, there's no rectifier, circuit board, or other junk to go wrong, and if you have experience with other designs, you'll know they fail you all too often.  We created the PMG out of our need for a more dependable and reliable solution.

Please report HERE any errors, omissions, or suggestions to make this page better, I hope it helps at least one person to be more independent.

While the Senate, Congress, do all they can to make you more dependent on them, we'll continue to try and do the opposite, make you as independent of the repair shops as possible. 

 and others too ignorant to note which way the wind is blowing. electricity is dangerous! It can kill you. I have no license, and no authority to tell you how to do any wiring or installation in your City, County, State, Province, Ward, District, etc. Always consult the proper authority, and follow all guide lines they suggest. Look to the Utterpower ST pages, the Utterpower CD, and Bill Rogers Book for additional information that could be of interest and help. Always drive a ground rod, or provide another suitable ground for the generator case, generator frame.  Prefix your Google search with the word Utterpower to find things here quickly. 

One closing message about finding/correcting wiring errors, don't move your connecting wires around to match up with the error, make sure the wires coming out of the Gen head are laid down onto the proper terminals 1,2,3,4, otherwise, you just leave a condition for you or another to stumble over, maybe years later when you disconnect for some reason and move it to a new location. I've seen a lot of people make their own traps to later step in.

Here's a page added to help you understand single phase power, and how it is delivered to your home commercially

George B (always the student, always learning)

Utterpower.com   

Foot Notes:

*1 KISS  "Keep It Simple"  Kiss Engineering examples include the brilliant, and brutally simple diesel injection pump using the helix to control the pump stroke. These pumps are simple yes, but manufacturing requires a high degree of precision. We best not confuse KISS with low precision (stove bolt) approaches. The PMG is a similar example, it is not a back yard creation by any means; but it is durable and easy to maintain.