Jim,
For your use there is nothing wrong with a 2-pole alternator. The 2-pole (3600 rpm) unit is there for a reason, and for the most part meets its intended purpose.
Most 2-pole heads are geared for the mating to a gasoline engine, which usually produce their max Hp at 3600 rpm. Can they work on a diesel, of course they can. Would we try and run a diesel at a consistent 3600 - of course not.
For everybody to know, the majority of alternators are produced in China. This can be in component form or complete assembly. Regardless of where you purchased the unit (alternator), it will have some kind of Asian origin.
Back to the 2-pole. The 2 main disadvantages are 1) Noise and 2) Lightweight aluminum
The noise factor comes in the form of having to run an engine at 3600 and the lightweight aluminum can and will take away from the longevity. Of course your unit is not intended to be a "prime" unit - so you should get by fine.
Below are the main reasons people are buying the 4-pole alternators.
1. Many take comfort in the heft, and they are VERY heavy.
2. The ST utilizes brushes, making most maintenance a breeze. It has to be. When you get into a 4-pole cast head, the average person cannot just toss it in the truck.
3. Many people want their genset to be diesel, for many reasons, and the 4-pole fits the bill better.
4. Cost is another factor. Dollar for dollar, a person will get more Kw for the buck via this old and proven technology. (2-pole heads are just not easily available in the higher Kw ranges)
5. After the storms last year, throughout the country, many people who were reluctant to even own a generator now want to own one, but, they only want to make the purchase once.
6. The ST heads are meant to be repairable. This gives many comfort. Especially those that believe in maintaining and repairing what they have vs. purchasing new.
We could list another 30 reasons why, but you have been reading up, so you get the point.
As for the drawbacks to an ST alternator, there is one. It is the fact that they are HUGE. Extremely heavy. Our ST-30 comes close to 700 pounds! Very heavy castings with lots and lots of copper. The ST-12 is not a whole bunch smaller in size or weight.
By now, with all of your research, you should be feeling comfortable with your configuration. When you have completed your backup power plant, you will be overwhelmed with satisfaction!
If we can assist you in any way, please feel free to PM or email. We help many with their self-made configurations and we even encourage it.
