Is anyone using a PMG

[assiduous1]

Thanks All,

I've been in Kentucky and unable to respond.  Looks like this is a thicker issue than I had originally thought.  I was surprised that nobody was using one of Utterpower's PMG.  Although at $650-700 big ones, their not giving them away either.  Still I would like to have something that produces a cleaner sine wave and has fewer parts than traditional ST. 
If anyone runs across a 3-4KW 120V PMG, like Utterpowers, I'd like to know for comparison. 

I was unable to find the web site that talked about PMG's having a bit more starting power for heavy loads.  They could have been comparing PMG's with a self-regulating generator, which can have some voltage problems when starting a heavy induction motor.
I'll keep looking. 

Thanks for everyone's input.  "500 heads are better than one"

[mobile_bob]

i would like to throw some observations/thoughts/theory out there for discussion as it relates to "self" regulation of a pm head

having seen one of these heads they are physically about 150% larger than the typical 3600rpm 10kwatt head such as those marketed by harbor freight,
and considerably heavier as well.

so in reality if the pm head was a wound field unit either brush type or brushless it would likely carry 15kwatt (intermittent) with a regulator

if you consider the same 15kwatt generator and provide it with a fixed current to the field so that it is providing 125vac at say 1kwatt output
it will likely not droop much with the same excitation going from 1 to 2kwatt and from 2 to 4 kwatt as well.
(the neo's provide fixed excitation of course)

there is a curve with a flat area where the alternator can provide pretty close voltage regulation (little droop in voltage) after which there must be
more excitation current to keep the curve from falling off.

this is the key to success with a pm head, it must therefore be overbuilt, so that the flat part of the curve will be as wide as possible so the droop is within
spec's

this cannot be done with just any pm head, if you were to size it appropriately in comparison to a brushed or brushless 10kwatt head, it would be about 1/3
its physical size and its self regulation would be dreadful.

so the pm head has to be over built in order to get a satisfactory and within spec voltage regulation (low droop), and things like close tolerances, very good neo magnets
are but a few issues.  the need to keep the unit sealed so that the neo's are not subjected to moisture make for cooling issues as well, so a proper design would dictate that the alternator would therefore have to be built much larger in order to have enough surface area to dissipate heat. 
careful design and tighter tolerances generally lead to higher efficiency, higher efficiency units generate less heat, less heating makes the job of cooling this pm head easier and allow it to be sealed up tight..

anyway, my bet is if one were to take an st15 head
and provide a fixed current to the brushes (no connection to the harmonic winding) and set it to provide 120volts at 2 kwatt
the voltage likely would be about 125 at 1kwatt, and 115 at 3 kwatt, so the self regulation at that power level is acceptable
if you want to put up with a huge overbuilt genhead. one must also bear in mind that the st head is nowhere near as efficient or built to as high
of a standard as the pm heads, so therefore even in this example the droop would likely be larger than that of a well designed pm head.
(this example is for illustration purposes only, and i am not suggesting it is a good idea.)

just thought i would put forth my thinking and i invite comment

bob g

[ronmar]

Still I would like to have something that produces a cleaner sine wave and has fewer parts than traditional ST. 

I don't think you are going to find a PMG at a reasonable price.  They are just not as numerous hence the higher production cost and end price.  As far as parts go, you are going to be hard pressed to find anything other than a PMG that has fewer than a ST.  So what exactly is your aversion to the ammount of parts in a ST?  They are brutally simple as is...  Shorty of re-winding it, I have at least one spare of everything required(rectifyer and brushes) on the shelf and I don't need to even crack a manual to swap out these parts if there should be a problem.

If PMG's were better than sliced bread, and offered an overall cheaper or more efficient alternative(less production cost, less materials to produce, lower failure rate/lifecycle cost) then I think you would be seeing them used more.  But the fact is that you are not, as they probably don't have any real benefit over the conventional rotating field type, either brushed or brushless.  Falls back to the "if it works, don't F&*^ with it" principle. 

Want a better waveform? well lay down some extra coin for a better made/skewed rotor head.  I am pretty happy with my ST, it feeds my house just fine.  And quite frankly, a working ST in the shed beats the heck out of anything else made of unobtanium that you cant afford, when the commercial power is out.

Good luck with your research.

[rcavictim]

There are clever techniques available to change the magnetic flux level at which a magnetic path in a machine saturates through active control.  An example is a magnetic amplifier, also known as a saturable core reactor.  I hereby postulate (and lay claim to the invention) that techniques along these lines (of force, pun intended) ought to be able to be applied to the workings of a PM alternator to boost the flux level of the field poles in rythm with load current rise.  The load current could perhaps be routed through some helper windings imbedded in the magnetic medium between the neo field magnets and their corresponding pole pieces to vary the amount of magnetic force seen at each field pole, increasing the pole piece flux as the load current becomes increased or decreasing it according to viced versa.

This technique may be able to extend the 'flat spot 'which Bob described being achievable by making the basic PM alternator 'stiff' from an abundance of iron and copper.  It MAY even be possible to develop a desired amount of regulation at the same time as cutting costs and materials in the iron and copper arena.  I would call this device a "Smart PM Alternator", or "Self-Regulating PM Alternator".   

[mobile_bob]

RCA:

good one!

having given this pm thing another thunk or three, how about this

take a standard squirrel cage induction motor and inset neo magnets within the poles of the squirrel cage
that way it self excites, and as the current rises in the stator there is more current induced in the squirrel cage.
more current in the squirrel cage the stronger the poles of the rotor, stronger the poles the stronger the induction to the stator.

this might broaden the curve flat ? seems like it ought to work.

for all i know this is how the pm alternators are designed, i sure as hell am not going to buy one and take it apart to see!
all i can see in taking one apart is severed fingers, and damaged magnets.
one of those "if it ain't broke don't mess with it", which is closely followed by
"some things i really don't need to know"

if it didn't we could always think it should have

bob g

[rcavictim]

RCA:

good one!

having given this pm thing another thunk or three, how about this

take a standard squirrel cage induction motor and inset neo magnets within the poles of the squirrel cage
that way it self excites, and as the current rises in the stator there is more current induced in the squirrel cage.
more current in the squirrel cage the stronger the poles of the rotor, stronger the poles the stronger the induction to the stator.

this might broaden the curve flat ? seems like it ought to work.

for all i know this is how the pm alternators are designed, i sure as hell am not going to buy one and take it apart to see!
all i can see in taking one apart is severed fingers, and damaged magnets.
one of those "if it ain't broke don't mess with it", which is closely followed by
"some things i really don't need to know"

if it didn't we could always think it should have

bob g

I'll have to ponder your idea regarding the induction motor.  I recognize that there is a fine line between flux control and trying to get 'free energy'.  Not sure which side of this line your idea fiits here. 

I have reserved the possibility of making my own PM alternator by making a custom field rotor out of neo magnets (already purchased) for my wind turbine.  It is not likely ideal but until something better comes my way it may be my first option.  Motor is a 575 volt, 6 pole (1200 RPM) rated at 20 HP.  I am hoping to get twice this amount of power from the machine at rated wind but since most of the time the machine is putting out far less than nameplate this might work out well enough to be quite useful.  I am attracted to the high voltage and low current (~20 amps per leg) which makes an inexpensive #10 extension cord to the house work as a hookup until a proper buried conduit line can be installed to the turbine.  A motor driven automatically driven variable autotransformer (3-phase Variac or Powerstat) at the house will turn this into a stable lesser AC voltage, wild frequency, feeding a battery charging xfmer and full wave diode bridge.  Heater elements can use the raw levelled AC from the autoxfmer output.  60Hz 115 volt loads will be on inverters from the battery bank.

We had the rainiest summer here on record and I have lost a good 6 weeks of it due to chronic illness. I have been slugging away at this project entirely alone here. Nevertheless I can proclaim with immense personal satisfaction that the massive tower will actually be completed this year!  I am painting today.  This leaves only about 25% left work to do for project completion which I should have done next season.

[mobile_bob]

for godsakes please don't put me in the "free energy crackpot"group!

what i have described whether it would work or not, would still require input of torque to produce power, and no free lunch.

bob g

[rcavictim]

for godsakes please don't put me in the "free energy crackpot"group!

what i have described whether it would work or not, would still require input of torque to produce power, and no free lunch.

bob g

Don't worry Bob, my use of the term 'free energy' was not intended to describe the resultant system, so there was no intent of accusing you of persuing anything considered fringe science.  I was refering to the way a sub system within the machine, in this case questioning if the existing shorted turns contained in a factory induction motor armature would actually operate as you proposed...or not.  My initial reaction is that it would create a demagnetizing sinusoidal flux that might weaken the magnets in time.  That is another topic and question in itself as we have seen.

In my invention the helper coils would have to be excited in one direction only so as to be neutral or add to the magnetic flux, so a form of current xfmer would have to be used in series with the machine AC output and the power to modulate the helper coils derived from rectifiers.  This would be like instantaneously replacing a section of iron in the pole piece's magnetic path with an active DC excited electro magnet arranged to add to the field strength, and in varying degrees.  AC excitation would not necessarily be desireable here IMO.  Of course the next step is to R&D the idea and see if it can be made to work.  I see your suggestion as adding AC excitation, not tied according to load as much as to sinusoidal output frequency.  Power regulation does not need to occur at this rapid rate.

Speaking of free lunch, stomach is grumbling!  Gotta go. 

[SteveU.]

Guys,

If you haven't already, check out www.marathonelectric.com/generators/faq.jsp for what they've been been doing with PM's for field excitation and stabilization. And their read on induction motor generation useability and limitations. Both interesting.

Mobile Bob for the prices of these promoted 3kw PGM generators assiduous1 has now announched to the world: I'LL TAKE TWO please.
This is a no BS, serious as a heartbeat offer.
Two units, your location, any reasonable broker expense to you. And yes, I'll pay our 8% sales tax.
It's Time to stop the "selling and "promoting" start suppling the real needs of real people.

Steve Unruh in Yacolt Washington USA with an off-grid shop with NO AC power.

[mobile_bob]

Steve:

i don't sell generators of any type, i do however argue counterpoints a lot!

anyways check your pm's

bob g

[assiduous1]

Sorry Steve, I didn't know I was letting the cat out of the bag.  I know of a couple of people that have been in contact with utterpower about their PMG.  I didn't think that they would mind (or anyone else for that matter) about mentioning prices that they've provided.  Anyway, check them out, there around Tacoma, WA.  Not sure how close that is to you.  Seems like the crowd here is sticking with the ST head instead.  If you end up getting one, Please let us know how it works. 

[SteveU.]

Ok folks its been a long wait (at least for me).

I sit here with my feet resting on my new AC generator head.

After eight different Emails and a month and a half of waiting I finally conseded that Georges PMGs are truly made of UNOBTIANIUM.

ONE phone call and Eight days later I recieved a brushless ajustable transformer regulated Mecc Alte 8.5 kw unit. This is one of over 2000 of this model distributed in the US since 1999. Soft parts (10diodes and two thyristers) are as close as the nearest Radio Shack. Hard parts UPS from Illinois,. or one of the five AC motor rewinders within an hour from my house. Bearings: common; any bearing house. My unit has a skewed rotor. Is built under ISO9001 controls. Meets CE, CSA, and UL standards, testing and certifications.

So yeah I've jumped down off my fence with my feet planted firmly onto the side of copper, iron and steel.

I want to thank those of you who listened to me talk and offered me your spare/unused units.
Especially thank cujet for having the courage to speak up and say "My ST waveform sucks" It was one his old posts that had the Mecc Alte recommendation. I always knew I could get a Marathon/Newage-Stamford/LeroySomers, ect for a price. $2370 in the case of the Marathon, the others more. The MeccAlte is between the price of an ST or Georges PMG in price per KW. Less than 1/2 the price of a Marathon.

I did want to use the PGM. I had  confidence it would work. Confidence based on 20 years using different PM motors in different cicumstances. I was more than willing to risk my money to try it.
But it doesn't matter...BECOUSE ITS MADE OF UNOBTAINIUM!!!!

Now the rest of this post we'll call STEVES RANT.
So please some of you turn away. No foul language, just lots of attitude. Just like George and Joel.
And I apologise to the Canadian and New Zealand Associates. I do not know you, by all reports you are both doing good service. Your web sites look well done and informative. Just realize who you've associated your selves with.
 Your USA associates are my Neigbors. One is 45 minutes away and hides behind the anominity of Ebay. Dealing with him is like doing a drug deal in downtown Portland. The other 3 hours from my front door obscures him self behind a self made maze of Email suffixes and  ocasionally deigns to come out give us "the Word".
Niether is a supplier becouse they don't supply!!
 Not a response to multiple engine and ST gen head requests in July. Finally a responce after multiple attempts in August for an ST head of, "No soup for you." Then a string along about PMGs thoughout September into October. Now it's cold and raining. And mud, mud, mud.
 Well thanks. I now have a better engine with NO SAND and a better gen head that WILL run a low amp rectified HF TIG AC/DC welder so I can weld my stainless and aluminum.
I know some on this forum have received service from George and Joel in 2005, 2006, 2007.
Tried lately as a newbie??
At least have the decency to give us the password, "Always mention Georges CD."
I know that I AM a grumpy, grouchy old man. 15 years ago when I knew after 17 years I'd finally spent my wad (of patience) I had the good sense to get out of customer service and  back into onhands work.
 These two are long over due.

So not being suppliers that means George and Joel are merely promotors just like the  much malined W.A.

None of these men chose to be forum members. No forum member has been mentioned negativly in this post. No real supplier has been promoted over another. Just my 2008  negative experiences with these two huckster, shuckster, promotors.

SteveU.

[mobile_bob]

this whole thread really became quite a mess didn't it.

it starts out with a guy looking for availability and info on pm heads

it progresses to Doug and I getting crosswise with one another, and him leaving

then it ends with more bashing of local suppliers, suppliers a hell of a lot of us have a good relationship with
and depend on for support.

all in all not a very productive thread, and certainly not a shining example of what a forum should be.

Steve, back on sept 5th you asked me to get you one of the utterpower heads,
to which if i recall i let you know i don't sell or resell,, i am a buyer and end user.

on sept 10th you asked me to get you 2 of them, to which i told you to check your pm's
in that pm i told you i would check with George when i could. i also offered a matched pair of SD (welding heads)
to you out of my personal stash for half of market because you told me you were desperate for genheads.

i made a special trip to see George on your account, i have no idea why you cannot get ahold of him
perhaps your emails are getting caught in a spam filter i dunno. Anyway i took time out of my day
and burned my gas in an effort to find out what i could for you.,

the thing is you never responded to my pm to you so i just figured you were no longer interested, plans had changed,
you weren't serious, or you were busy.  maybe it is my fault i didn't try and contact you again, but i got busy
and how much effort do you expect from someone that has already spent his time and gas getting info for you. you are a relative
new guy here and i don't know you personally so how much effort do you expect?

so obviously you didn't get the followup, what i found out was all of the shipment had been spoken for and George was
busy shipping them out, every damn one of them.

now consider this, here i was, in person, being a person that has bought stuff from George in the past and even i could not
buy one of the heads for myself because they were already sold!

so i don't know what to tell ya, i guess if you want one put your name on the list for the next order?

but that might be kinda tough? gettin on the list,
coming on the heals of your last post.

"a teaspoon of sugar goes alot further than a gallon of vinegar"

so you don't like George or Joel, well i suppose that is your perogative
i like both just fine, as do one hell of a lot of other folks that depend on them for info and support.


bob g

[SteveU.]

To clarify:
My post on 10/22 was to answer the question assiduous1 had asked when he started this thread.
"Is any one using one of Georges PMGs?"
As posted on 9/11 it sounded like I was going to be.
My answer now a month and a half later is NO; because I was unable to get one to use.
The balance of that post was my what I was going to use as an alterative instead of an ST or PMG, functionally and price wise; and why.
Two hours after becoming interested in these PMGs I knew who the manufacturer most likely was. They DO show a nice picture on their web site. I could have had two of these here through an overseas broker over a month ago. But I'm the one who encourages people that your only real warantee on imported product IS through the importing dealer/distributor. Experience. Been there.

Mobile Bob to clarify:
You and I DID interchange as you indicated: first PMs, them a couple of Emails.
Yes you did offer me a pair of 220volt only SD5 heads cheap. I Emailed you the same,"Thank you, but NO" responce I given another member who had earlier offered me some 110volt only heads. That I would need both 110 and 220 in my shop. My guess is when your computor failed for three days in September that Email was lost. Want copies? My 10/22 post did thank you both and a thrird member for the offer of a Marathon pancake unit: they are just too hard to fab a belt drive.
And I do believe you did go all out and try and squeeze out a PMG from George for me. Your efforts Did eventually produce a result.
Would you like one of my junker Electrodyne units? Other have rewound them to 110 volts to use on windmills/hydro.
George B. did eventually send me a long Email ( my first responce ever) on Thursday 10/9 with the updated PGM specs and conditions of sale. I immediatly Emailed him back affirming I would accept responsibilty for useage, hazard and installation: and asked for a mailing address to send a chashiers check.
I'm still waiting for the mailing address or any more word.
In the mean time my perviously ordered MeccAlte head arrived.
I now concede that the 66.6 115v or 33.3 230v is all I'm going to have to work with. So instead of getting an old $5-600. 15-20 year old amp hungry transformer TIG welder, I'll add the set aside $725. PMG money and buy a more modern low amp input inverter TIG. Simple decision. And now finally with knowns I can get on with permanet engine mounting and wire up.

Assiduous1 it does make one wonder how over a hundred PGMs could have been sold and no one if talking about it or posting pictures.
I've seen this before here in the N.W. home to too many kooks, Clans, and CULTS.
I chose not to swear an oath of silence so I could enter the Utterworld and recieve my token PMG as key to the Utterverse.   Yeah, I like science fiction too.

Mobile Bob I'm really not going to get into a war of words with you over these two hucksters.
They chose not to be part of this forum.
Here on in I'll just be posting web sites of alternatives.

Steve U.

[Tom]

What most people are seeking with a PMG is higher efficiency and simpler design that promises to be less prone to failure.