Author Topic: ST 7.5 and ST-1  (Read 4995 times)

bandmiller2

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ST 7.5 and ST-1
« on: May 19, 2012, 03:00:44 AM »
I am planning to hook up a two bearing generator/alternator to my Lister ST-1 10.5 HP.I hear conflicting reports about the ST gens. are they decent and reliable.?? It will be used for standby power and I 'am not a fussy person a little flicker doesn't upset me.I have an outside furnace with circulator motors that must be run for heat and to prevent meltdown.I have one of those agrivating little generators  hovering at 3600 now, it does for short term but bites it with a long outage. What options are important. Thanks Frank C.
Fast cheap and easy are seductive sirens,its a rare man that does not court their pleasures.

bandmiller2

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Re: ST 7.5 and ST-1
« Reply #1 on: May 22, 2012, 11:18:49 AM »
Guess this subject has been beat around too much.For better or worse just ordered a ST-10 for my lister. Frank C.
Fast cheap and easy are seductive sirens,its a rare man that does not court their pleasures.

38ac

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Re: ST 7.5 and ST-1
« Reply #2 on: May 22, 2012, 12:15:14 PM »
Guess this subject has been beat around too much.For better or worse just ordered a ST-10 for my lister. Frank C.

My heating is same as yours with an OWB ;)

I don't have enough operating experience to answer questions like that but before I bought mine I read many pages here and over at the other forum. Seems like the general consensus is to stay away from Indian units, remove the factory doghouse and replace with a good UL junction box large enough to contain the connections and check the bearings for quality and replace them if questionable and always replace the factory grease with American made stuff. I would not be supprized if some of the issues have been addressed by Tom Osborn as he is very quality orientated.but you will know when you get your units. If the doghouse and connection board seems cheesy then you need to plan on upgrading. I have ST5 and 15 from him and they are both producing very nice power, Hz and volts are fine without any add on regulators and they operate everything at the house just like line power as far as I can tell.
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BruceM

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Re: ST 7.5 and ST-1
« Reply #3 on: May 22, 2012, 04:48:15 PM »
For a "value" generator head the ST's are worth considering.  The ST's have some well known issues (my ST-3 had bearing and diode bridge/doghouse failures within 100 hours of operation) as 38AC states. Some vendors may have addressed these for you.

In my opinion they need an AVR added, driven from the mains not the harmonic winding, which is easy and relative cheap to do.  Then the output waveform is acceptable for most applications and most solenoids and motors won't growl or buzz. The degree of "ratcheting" and spiking still present on the AC output does vary between units/vendors quite a bit. I have seen some o 'scope shots sent to me by guys with ST heads working on my homebrew AVR design that were pretty nasty. Microprocessor controlled battery chargers or PV type charge regulators sometimes refuse to operate with ST outputs without some effort to clean up the spikes and EMI.  (Motor run caps on the output and sometimes metal film caps on the bridge.)

You will have to do regular slip ring/brush service, which is easy.  Virtually no problems or reliability issues outside of the known issues have been reported, probably due to our best vendors/importers doing a good job of weeding out the worst ST makers years ago. Utterpower reported  on the known issues and on some of the flakey, poorly built lightweight ST clones a decade ago.

If cost isn't an issue, there are certainly better quality, brushless generator heads, with skewed  windings to avoid steps and spikes on the AC waveform, built in AVR, good bearings, and overall much better quality control.  Marathon is one of the best, Mecc Alte (sp?)  has also had some favorable reviews, and there are some others though my memory fails me on names. I've seen o'scope shots of Marathon waveforms that are such lovely clean sine waves they make me envious, and others that were a big improvement over the STs.   Permanent magnet generators are an interesting option for those that loathe any electronics.  (Though flicker will be comparable to a non-AVR ST head.)  

ST heads are like an old Volkswagen bug- noisy, not the best ride, but they'll get you there, usually. Some people want a better engineered, quiet, smooth vehicle and are willing to pay for it.  No fools, either way.


« Last Edit: May 22, 2012, 07:17:08 PM by BruceM »

dieselgman

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Re: ST 7.5 and ST-1
« Reply #4 on: May 22, 2012, 07:33:15 PM »
We have always favored the robust Marathon designs despite their high cost. They are easily serviced and even rewound (in North America at least). Inherently regulated and nearly bomb-proof out of the crate. That said, they are producing their stuff in China now. I suppose no real loss in quality but the change (I believe done 3 or 4 years ago) makes me uneasy.

The Euro designed heads have been very common in our service work - Leeroy Somer, Mecc Alte, Stamford and the like. When these types fail, we have NOT had good luck with rebuilds. Metric wiring and calibration issues (again in North America) have been roadblocks. Lister/Petter America has widely used Stamford heads with their Hawkpower line and they are fine units though completely AVR dependent and higher maintenance than Marathon.

The Chinese ST heads we have handled have been AVR equipped and no real problems except for what is already fully noted here regarding bearings etc.. I think they are a reasonable compromise for their low-cost. If you have a big budget and want a cadillac, buy the Marathon. Just don't assume you will be getting an American made product any longer, despite its long history here.

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bandmiller2

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Re: ST 7.5 and ST-1
« Reply #5 on: May 25, 2012, 12:49:03 PM »
38ac,just ordered a ST-10 from Chris at Central Georgia,asked about different options on that unit,got the impression they order the best and dropped the rest.Asked if there was anything I needed to do or check on the unit he said just belt it up and use it.Of course thats the dealer talking.If you twist their tails the chinese can build good stuff,as dieselguy Gary says Marithon is built there now.Just a real shame what the EPA and OSHA have done to our foundries and heavy industry. Frank C.
Fast cheap and easy are seductive sirens,its a rare man that does not court their pleasures.

bandmiller2

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Re: ST 7.5 and ST-1
« Reply #6 on: May 26, 2012, 02:18:50 AM »
My ST-10 showed up today Old Dominion freight lines.Theirs a signed slip outlining what Central Georgia Gen.has checked,brushes and holders,slip rings,shaft and bearings run smooth,windings,components in the doghouse tite,and a resistance checkto the brushes.All and all it was a pleasant experiance they shipped tuesday and I got it friday.Now the balls in my court.Their good folks to deal with. The truck driver was impressed with my old JD 60 tractor with loader and forks plucked that heavy sucker off the truck in two minutes. Frank C.
Fast cheap and easy are seductive sirens,its a rare man that does not court their pleasures.