You’ve seen it, everywhere you go there are dirt cheap generators and most of them will run the 50 hours that 99% of all owners will ever run them. For the other one percent (you and me) this becomes a problem.
I have one customer who finally found a quality 6.5 KW generator head that is advertised as commercial grade for $1500.00. This is a slim market, and few are interested in it, so when you look at comparables, you might ask yourself, for what market was this product developed, and how will it hold up in an off gird environment with steady use?
Hydro is even more demanding, and slip rings on the STs (Economy Play) have been known to erode quickly in hydro service. If you deploy an ST in continuous service, consider installing a polarity reverser and a flasher circuit for the field, and change polarity once a month. I do not understand the slip ring erosion well, there are just too many variables, and who’s to say that the brush material, the alloy that is used for the rings, is always correct? We also have other variables like spring pressure, humidity, temperature, and I have noticed that some generators, including some STs, use considerably more power in the field (higher voltages and high current) than similar generators which likely aggravates the problem. As I have said elsewhere, the simple ST is VERY similar to about 99% of all the hardware store generators as per its field excitation and how it gets the job done. Do note that the PMG doesn’t have any of this, so we side-step all the wear issues.
It is a fact that there are many Chinese products sold that are made not to use. Examples being the many Chinese horizontal engines with radiators on top. Many fail at about 100 (give or take) of running. China now has serious problems that plague them. Those that understand just how hard it is to recover after losing all your trained and key people will understand why there are a lot of goods coming out of China right now that are no where near the quality that they achieved when orders for goods were brisk. Having your own quality control program in China is presently critical.