ST Gen heads - any difference?

[zacksstacks]

Ah, I have questions!

I've been to Utterpower and read about why the PS ST head is the best. How does that tally for folks who own them? Does a plastic fan really affect the reliability? Is the weight a real factor? As an example locally a fellow sells an ST-5 head which weighs about 250lbs and has a plastic fan. I think the PS unit is said to weigh 295lbs and has a metal fan. I'd guess the PS unit has better bearings? or at least better grease? Is there any correlation between clean waveform output and weight/price?

So, other than buying them and trying them out, how does one pick a good ST gen? Are there good indicators to watch for? To watch out for?

BTW, I use the PS unit as the example due to the wealth of detail on the Utterpower site, not to point to it in particular... 

PS, do they really use "Yak fat"?

[okiezeke]

Zack,

ST gen heads vary from "trash" to "good, but need repair".  Some folks have said their ST  looked like it was built from scraps off the floor.  Others looked almost 1st world

Bearings:  I would grab the shaft and give a big turn.  If the shaft rorates 5-6 turns and the bearings are silent, then let em stay.  If the shaft makes crunchy, grinding noises, better replace em with good 1st world perm sealded ones(under50.00 apiece).

Take off the end access cover.  Look at the coils.  Are they completely encased in epoxy or paint.  If so, leave em alone.  If you can see individual wires, and wiggle them with a fingernail, you need to disassemble, clean, and give 4-5 coats of glyptal

Look in the doghouse.  Give every wire connection a good tug.  If all are solid, they're OK.  If one or more pulls loose you need to recrimp or solder every connection you can find.

Also in doghouse.  There will be a little shoebox shaped rectifier bridge.  Had 4 wires connected.  If this thing has chinee writing on it, into the trash with it and replace with a good american made one.   Cost 3-8 dollars.

There are three dealers I have dealt with who try to get good stuff.  Eric, at RockyMountainPower Solutions.  George, At Utterpower.  And Mike at listeroidusa.  I'm sure there are others, but with these 3 you wont go wrong.  Of these, Eric at RMPS says he has generators with real voltage regulators.  This would be a nice thing to have.  Your computers, electronics, back up power systems, and most every thing else like consistent voltage.  There at least 2 or 3 folks looking to build/sell an add on voltage regulator.  These should be under 100.00 and do the same job.  Have not seen one get to market yet.

George Eric, or Mike will sell you good machine.  You still need to do all of the above tests, and be ready to disassemble, fix, and reassemble.  If you cant or dont want to tear one down, mabe the ST is not for you.  There are many quality american built gens.  Starting a 2-3 times the price of an ST.

Clean waveform.  Wow, what can I say??  Buying a good american bridge rectifier and putting a 5000uf electrolytic capacitor across the output has been reported to help.  A well built voltage regulator SHOULD have a clean filtered output.  No reports yet on whether they do.  Another thing to ask is, are the stator windings parallel to the rotor, or are they angled 10 or 20 degrees.  The angled ones are supposed to have a cleaner output waveform.

Good luck,  no, I haven't seen any yak fat......yet.

Zeke

ps Doug has forgotten far more that I know about generators.  He is the real expert on the forum.  Might ask him.

[Doug]

Zack I can't give you a fair or honest answere.

I have just finnished a private message with a fellow who has 4 ST heads. Two from one of the before mentioned venders that had serious issues that he had repaired at a motor shop.

I think its a case of hit and miss.

I would prefer a head with extra iron around the bearing housings incase you need to have it rebuilt at some later date ( this will make the machinists job a little easier ). But a lighter head with good machining that doesn't need work is better a heavier one that does. Bigger bearings on some VS smaller ones realy doesn't make much difference if you have replace them because they are full of dirt or bad grease and of the open type. But bigger with good closed beaings in a well machined end bell is better so you can see where I am going.

One thing we haven't yet looked into is the wire size used, and the redundent 50 Hz taps on some heads. I only found one company in China that was willing to talk about this with me and they realy weren't interested in changing anything. I think its probably a case of minimum wire size and general purpose heads with the extra taps being the most likely thing you will find because the Chinese realy aren't interested in building a special North American head.

There is also the need for a certification that no one has adressed yet and this is only coming to light as an issue now. I'd like to see a CSA or UL lable on a head with a minimum of 350-400 cm per amp, a flux density of around 100,000 line per inch in the teeth and an air gap roughly 45,000 to 50,000. I'd like to see 2Z bearings, better brush holders and brushes, better slip rings, even better painting.....

I don't think anyone importing these things has asked these questions or gotta reply they could get such a head.

Back to your questions:

Plastic fan vs Aluminum.
I'd rather have a good plastic one than a bad aluminum one and, and there are also ballance issues the metal fan since they may not ballance the rotor at the factory at all. And ballance is also can be off just by the way the coils pole faces and windings were made so its a crap shoot.

Electronics are a crap shoot since we have no idea who makes them and what standard ect...

Bearings
You get what you pay for, a brand you have heard of like SKF, FAG ect would be better JinShoo what the heck so you haqve to decide if you can live with and trust what you have or or not.

Lastly there is a lot of bad information and BS out there. Do you realy think you can spin your one coils and rewind a head at home? And a branded head is one you will never know any history on, so before you buy an ST head find out who realy made it and try and find some toerh people who have that make and see if they have had trouble with them or not. A branded head like the RMPS and Powersolutions heads could be made by anyone some could be realy good or not so good and here's the problem. If they get some great ones they won't tell you who made them to protect there source, if they get some crap ( and I'm not saying they do this but its probably a temptation ) they don't tell you who made them and dump the crap on Ebay where you can't tell the difference until the crate is opened.

I don't think any venders actualy open and inspect there ST heads so if you get a dud you could be on the hook for it. I'd ask in advance what happens if you get a damaged unit or one that fails to perform because of manufacturring issues or doesn't meet the requirements for field inspection ( eg the inspector won't accept it becuase it failed a 1200 V high pot test or the dog house doesn't meet with his aproval ect ect...).

Lots to think about eh?

Doug

[mobile_bob]

a couple of observations if i may

yes there are some vendors who will buy the cheapest head available,, some of them may be problems some may be just fine

there are also vendors who spend countless hours working with manufactures in china to have generators built to a higher standard
and when problems arise they press the manufacture to improve the process, and in the not so long run these vendors usually always have a
superiour product. powersolutions is one of those suppliers that makes trips to china and has for many years worked closely with the manufactures to
get the best product available.

we also have to understand these are good old basic timex's not rolex quality, they will do the job and do so for a very long time.

it has also be stated

"Do you realy
> think you can spin your one coils and rewind a head at home?"

Well for me,,, the answer is yes.  i know i could and will, i am contemplating a dual purpose rewind right now on an SD head,
and also contemplating a rewind to 3 phase 12 or 24 volt charging at 5 kwatt.

having rewound everything from slot car motors as a kid to several generators and alternators, i see the st head as not such a big
deal to rewind at all,,, as a matter of fact i see it as much easier because i can get my hands in there much easier that small frame alternators
or slot car motors..

i don't think it is a black art at all. perhaps not for the faint of heart,,, but certainly no hill for a climber.

just my .02

bob g

[xyzer]

I chuck the doghouse and mount the rectifier internaly and I believe George sells them configured that way with sealed bearings
If it comes down to a rewind I'll just order me another PS!! ......Not my way of having fun!...... I'll use my time doing some other not really KISS thing to the bottom end of my 6/1 or a different way of cooling.
Dave

[mobile_bob]

xyz'er:

awe your no fun!

i too have several of the PS heads both ST and SD and i find them to be an excellent value

perhaps it is based on my experience of having been faced with looking for a belt drive genhead over the
years and only finding 1.5 kwatt heads that turned 3600rpm and cost 500bucks,, i don't know... or maybe

based on my actually rewinding many alternators to get higher voltages, or generators that i not only rewound
but replaced commutators and custom built and fitted slip rings to in order to get 60 hz 120 volt power from.
all of which worked, some better than others, some with clean sine wave , some without, and all were alot of work!

having a ST head that needs to be gone thru and inspected, brgs replaced, doped and a few wires crimped properly
just doesn't seem like an issue at all to me, even if i had to rewind one!

i guess one does not have an appreciation for where i am coming from until you have taken an old delco generator, stripped it
redesigned it, rewound it only to find you need more turns on the rotor or stator or both.... then you get to tear it down and redo it.

at least with an st head i know the coil turn count and the size of wire to use

we have all seen how the indians built st heads,, sitting on the floor, in sandels, with the stator between his legs shoving in coils
and we should also know the coil winder certainly is no einstein!

if they can build it certainly a DIY'er with some ambition can repair or rebuild it? no?

bob g

[xyzer]

Bob,
I understand totally where you are coming from! I have a deficit in the electrical area as far as knowledge. I have no problem rebuilding them as far as bearings, turning the comutator and basically just upgrading the head or fixing there obvious quality issues. I take it apart and repair the obvious issues and put it back together. Not my bag but they are better than when I got it. I could rewind one but I would loose too many brain cells in the process. I've just been a machinist for 35 years and I'm going to stick with what I think I know not what I know what I don't know! I'll watch you do it sometime that would be more fun!
Dave

[mobile_bob]

Xyzer:

sorry the comment "awe you are no fun" was for you,,, the rest was for the masses
and not directed at you or anyone inparticular.



bob g

[Doug]

Bob are you winding coils on a jig?

And my statement about the home rewind not being realy all that practical also comes form the fact that the suplies to do the job properly aren't generaly available to the public

So just to satisfy my curiousity where are you getting magnet wire, slot liners, roof wedges, epoxy, phase paper, sleaving ect.

Doug

[mobile_bob]

Doug:

so happy you asked

i make up wood coil forms, and then make a trial coil to check fit, if ok all is good to go
if not i trim the form to correct the fit, wash rinse repeat as necessary

as for mag wire, i buy it whereever i can find it, surplus outlets have been a good source

the other stuff, slot paper, top stops etc i get from local motor shops... not all in the same place
is the key.

i have also been sent to a huge warehouse (because the motor shop didn't want to sell to me and
figured the warehouse would blow me off) at the warehouse they gave me samples (full sheets of various
thickness slot papers) and all sorts of top stops etc. all free because they didnt have a way to sell it in small quantity

you just have to ask and i ask alot everytime i see one of these places,, and then i write down their address
so i can come back in the future.

sleeving i got miles of it for something like 5 cents a pound surplus in all sizes up to an inch so i have several lifetimes of it
epoxy or varnish i get from other rewind suppliers

i also have bought every book on rewinding from early in the last century, where the process is laid out for guys that
were probably not the highest educated at the time, so the processes are broken down quite well.
they also did not have the high tech stuff we have today, so they used lacing methods to secure coils rigidly
so i learned to do that properly as well.

i figure if the old DCC (double cotton covered for those that don't know) wire was used a century ago, and methods to make coils were done with wood forms then
i can therefore use enameled wire and higher tech liners etc and get at least as good a product as they produced.

many of those old motors still run today, so they did something right in my opinion.

i love the old books with all the illustrations, procedures and materials,,,, and to a lessor extent their math
but i don't really need much math save for coil turn count and guage size to rewind a stator.

all i really need to do is take my time and map out what was on the stator core, placement, wire size, turn count
and replicate it. then lace it properly and secure it with varnish or not depending on my intended use.

bob g

[Doug]

The US navy had a good book I haven't seen in a long time that showed you how to set up a jig on a wooden block, this method works well. There's also the skewn winding method where you make one big coil and lay it in loops. An easy way to make concentric coils is with wooden dowls in a ply wood base.

Cotten sleaved wire ( oil soaked mostly in the old days ) worked fine but the limmits of organic insulation systems meant that things could not run very hot. This leads to lower efficiency, I know that sounds funny but its true.

Enamle wire needs to be varnished or the coating rubbs off and they short out....

Mylar sheets can be cut down to make your own slot liners....

That much said a proper winding head and skilled set of hands makes it a lot easier to lay your coils. You need to try and get as much slot fill as possible for the best heat transfer. There are a lot of other considerations but yes you can do it yourself.

I'm still suprised your able to get the materials, and impressed you've done it yourself.

Doug

 

[mobile_bob]

Thank you,, Thank you .. very much
(in my best elvis voice)

getting some of these supplies is like pulling teeth some days, so when i can score i try and score well.

another method i have used is to bring in a hd leece neville stator that has been torched and ask them
to rewind it,,, they usually look at me like i am out of my mind and say no way (because they don't want to mess with it)

so then the hook is set,, so i say fine,, sell me the stuff and i will rewind it myself
this usually works, because then i get past the gate keeper and am sent to a guy in the back to which
i ask for what i really need, get it and then he tells the guy (gate keeper) what its worth to which i pay
and get out before they get the story together.

i know this is somewhat less than honest,, but i am not taking away from their business, and am paying for the material
at the cost they want for it, so i don't feel guilty at all.

alternatively taking in a customers motor for service will get me into the shop where i can get end rolls at times for smaller projects

bob g

[Doug]

I knew an old fellow here in town who couldn't sit still. decided to rewind an armature for his wife's vaccume while recovering in hostpital from surgery......

I guess if you have the time on your hands and are prepared to work at it untill you get it right. I don't think I know more than two people now who have done it.

Doug

[mobile_bob]

Doug:

not sure but is there a compliment in there somewhere

i did a google search on rewinding stators and found many references to guys rewinding stators for motorcycle alternator
so in reality the st head is an inside out motor cycle alternator and much larger, which has too facets..

one you need more wire, and ..

two you have a bit more room to work?

i am thinking perhaps it would be helpful to do a pictoral with a step by step rewind of one of these heads for those
that are interested,,

i figure you would be the man to do something like that , you do a great job posting pictures and are a professional
when it comes to rewind... now all we need is a burnt out st head?

only problem there is,, i haven't heard of anyone with one that needs rewound, have you?

would be an interesting project don't you think?

bob g

[Andre Blanchard]

Thank you,, Thank you .. very much
(in my best elvis voice)

getting some of these supplies is like pulling teeth some days, so when i can score i try and score well.

another method i have used is to bring in a hd leece neville stator that has been torched and ask them
to rewind it,,, they usually look at me like i am out of my mind and say no way (because they don't want to mess with it)

so then the hook is set,, so i say fine,, sell me the stuff and i will rewind it myself
this usually works, because then i get past the gate keeper and am sent to a guy in the back to which
i ask for what i really need, get it and then he tells the guy (gate keeper) what its worth to which i pay
and get out before they get the story together.

i know this is somewhat less than honest,, but i am not taking away from their business, and am paying for the material
at the cost they want for it, so i don't feel guilty at all.

alternatively taking in a customers motor for service will get me into the shop where i can get end rolls at times for smaller projects

bob g

You may want to contact this guy.
http://hitorqueelectric.com/

He is on the electric vehical email list.
http://www.madkatz.com/ev/evlist.html
And I believe has sent supplies to members who wanted to try their hand a fixing motors.

I have not had any personel contact with him but he seems like the right sort on the list.  And I think he is in your part of the country.