Author Topic: ST power useless, Please assist me in improving the output!  (Read 30168 times)

cujet

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ST power useless, Please assist me in improving the output!
« on: February 25, 2007, 01:30:26 PM »
OK, I need some direction with regard to my ST power situation. I have a 15KW AVR ST head driven by a 20/2. It has extra heavy engine flywheels and an 80 pound gen head pulley. The following are my issues:

1) Voltage too low under heavy load (104), slightly low under no load (114), normal is 120 at my house.
2) Massive flicker
3) Wave form very poor
4) Nothing works properly, Microwave sounds funny and is quite slow, ceiling fan motors sound funny, water pump runs slow and is "quieter", UPS will not come on line, TV will not work, Sat dish will not work, in fact, my 11HP Subaru powers everthing just fine.

My guess is that the low voltage issue is due to the low quality circuitry not providing enough voltage to the field.


I am willing to build any circuit necessary. Fabrication skills are not a problem, nor are basic electronic skills. But I do not know where to start.

Chris

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rmchambers

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Re: ST power useless, Please assist me in improving the output!
« Reply #1 on: February 25, 2007, 02:51:55 PM »
What do you have for frequency?  It may be that you're not running with sufficient RPM's to generate the high enough voltage and the proper 60hz frequency.  Do you have a meter or a Kill-a-watt that you can see your frequency?  It sounds almost like you're running under speed.

Robert

retardo

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Re: ST power useless, Please assist me in improving the output!
« Reply #2 on: February 25, 2007, 02:54:57 PM »
1)disable the avr. The ones on ST heads are near worthless. Hasn't this been mentioned before?

2)modify the injection linkage/springs on the engine. Hasn't this been mentioned before?

3)set the HZ at 61 or 62 no-load, and you should see almost no change in voltage/HZ from a very light load to full load. Maybe 3-4 HZ. Hasn't this been mentioned before?

4)There are self-professed "experts" here who will fill your heads with mush. However, it does not change reality. A lightweight ST head with garbage circuitry (avr) is still garbage, regardless of "experts" who say it is the only way to go.

5)There are many, many thousands (or is it tens of thousands?) of ST and other similar 4-pole heads operating without problems in the USA on a continual basis. Think about it.
Fix courtesy of Retardo Mentalbum
« Last Edit: February 25, 2007, 02:58:30 PM by retardo »

dkwflight

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Re: ST power useless, Please assist me in improving the output!
« Reply #3 on: February 25, 2007, 04:26:21 PM »
My experience bears out what has been said. Set your freq. about 2 high under no load. So when you are at your average load you are at 60hz.

My tv seemed to work ok. The a/c, when running worked OK. The fractional horsepower condenser fan motor worked OK but was noisey. The Microwave worked but the voltage would sag at first because of the sudden load of 1500 watts.
My UPS did not like the power produced and would not engage.

The main problem was for me, the governor response.

The linkage needs to be correct, be able to apply full rack when the rpm drops.
The injecter needs to be fully bled out. Sometimes hard to do.
A lighter spring helped on the governor response.
Good luck
Dennis
28/2 powersolutions JKSon -20k gen head
Still in devlopment for 24/7 operation, 77 hours running time

ronmar

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Re: ST power useless, Please assist me in improving the output!
« Reply #4 on: February 25, 2007, 07:45:36 PM »
It does sound like you are running slow, How are you measuring frequency/RPM?  On the self regulated head such as the ST, you also need to make sure the RPM/voltage relationship is correct.  At 62HZ no load, you should have around 125 VAC or around 250VAC across both output windings(or across any 2 of a 3 phase head).  If you are less than this, is there a fixed(or large variable) resistor in the field circuit after the diodes?  This would limit field current and lower output voltage and might have been added to adjust for a excessive output at 60HZ.  If there is no resistor, check out your diode pack.  You may have a bad/open diode.  This would limit the current delivered to the field and lower the output voltage.

As mentioned here and other places, most microwaves build their pulse using the peak of the sine wave.  Low voltage or a nasty flat-topped sinewave will really limit the cooking power of a microwave.

Using the "Z" winding to make the power used to excite the field with no buffering effects the overall magnetic field. The small stock diodes are also working pretty hard to rectify it.  Someone posted O-Scope pics here of the sinewave from an ST.  Although having a pretty good basic shape, it has other noise humps attached most likley caused by the diodes closing(slamming shut).  They unfortunatly put noise spikes onto the output power that give the appearance of almost double the frequency.  These noise humps drive most UPS's nuts and they won't acknowledge it as good power.  I have some of my own theories on how to clean this up, and will add to the AVR thread when my experimenting is completed.
PS 6/1 - ST-5.

cujet

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Re: ST power useless, Please assist me in improving the output!
« Reply #5 on: February 25, 2007, 09:12:32 PM »
I use a kill-a watt to set volts and freq. The freq is a bit high due to sagging voltage. The max no load V is 116 at 63HZ. The AVR seems to be in series with the Z winding.

By the way, my linkage is full heim joint, well lubricated and spring'd properly. My no load to full load droop is about 1-2HZ. I will ditch the AVR and try again. I will probably put in a better FWB.

Still the flicker is very noye'n.

Thank you for the replies! I do consider a decent AVR to be a safe addition to an ST as long as it can be disabled when it fails.

Chris
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snail

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Re: ST power useless, Please assist me in improving the output!
« Reply #6 on: February 25, 2007, 09:21:16 PM »
Hi all,

Does anyone else notice that "Retardo" rhymes with "Guido"??? :D  :D

cujet

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Re: ST power useless, Please assist me in improving the output!
« Reply #7 on: February 26, 2007, 02:01:54 AM »
Will the main windings provide enough voltage during start up to drive the field? If so, is there a reason why this is not done?

Thanks,

Chris
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Horsepoor

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Re: ST power useless, Please assist me in improving the output!
« Reply #8 on: February 26, 2007, 06:49:45 PM »
Chris,

Interesting question. I happen to know your machine is setup at 62 Hz with an appropriate spring / governor control. So, I starting looking around and hit upon one Utterpower's links. Please review, perhaps this maybe a solution.

http://www.utterpower.com/UP_ST_KIT.htm

Bruce
GTC 20/2 down rated to 850 rpm - ST 15
Metro 6/1 800 rpm on cart - ST 7.5

Doug

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Re: ST power useless, Please assist me in improving the output!
« Reply #9 on: February 26, 2007, 07:49:19 PM »
Bruce:

Thats 29.00 USD for a steel plate, rubber gasket and replacement bridge.
In tottal about 5 bucks worth of parts and 10 min of fabrication time.

I've spent more money on dumber things, but I would never admit to buying a that.

Cuj:

A new AVR is coming its just a matter of finding time to build....

Chris:

The harmonic winidng is intened to change it output with load. "Leoroy Sommer" used to a CT arrangment to increase feiled current under load and that could be adapted to the ST as well but its been a lot of years since I look under the dog house of one of those. I wouldn't sugest this just yet as a fix just proof there is more than one way to improve on regulation.

Doug

Doug



Doug

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Re: ST power useless, Please assist me in improving the output!
« Reply #10 on: February 26, 2007, 09:00:26 PM »
Generaly the machines I service require a station garrenty from the Utility before I start and I climb in to service them. I haven't climbed into an ST head yet and looked around but I think I could manage.

But a trip to the local surpluys electronics outlet in your area or online at Abra electronics ect will set you up just fine.

You may also be suprised to know you don't need to buy a 1000 v PIV bridge with a 50 Amp capacity.
Does this help?

http://www.abra-electronics.com/driver/database.php?offset=30&search=rectifier

This isn't rocket science to set up and make, just keep your crayon sharp.

So tell me how long does it take you Retardo to make something like this?
How many ST heads do you have?
And are you perhaps someone with a vested interest in selling things?
« Last Edit: February 26, 2007, 09:19:00 PM by Doug »

mobile_bob

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Re: ST power useless, Please assist me in improving the output!
« Reply #11 on: February 26, 2007, 10:16:53 PM »
Doug:

surely one can save a few bucks if he is crafty and looks around a bit,, provided his time is not worth alot.

if on the other hand time is at a premium, and you have little of it that you are willing to sell for less than 50bucks an hour
you might do well in just ordering the kit.

two things happen

a. you save some time, and you get something that will work,, no muss no fuss,,, it just works

b. you support ongoing research and development by those that have more time than one might have on his own.

either way it is a win/win situation in my book.

i recently bought from George, a coolant plate and tstat housing for a changfa r195, now i won't tell you how much, but suffice it to say i could
build one for less,,, in material,,, and then only if my time is worth alot less than i can sell it for to a customer. and....  i help to support those who are
actively trying to support these engines..

now if on the one hand utterpower wanted 150 or 200 bucks for the upgrade kit for the sthead,, then that is probably pushing the envelope at least for
me... but i suspect there are those that make more per hour than me and would still find 200buck acceptable.

it is sort of like going to a steak house and paying 50bucks for dinner,,, sure i can by a steak at the store for 6 or 7 bucks, my own tater, and salad,, and save
maybe 40bucks.... but i am paying for a prepared product... and i don't have to go anywhere or do anything but drop my money for dinner.
and they do the dishes... similarly,,, i don't have to clean up my mess after fab'ing a plate, etc.

same goes for a bigmac at mcdonalds,, or laundry at the cleaners,,, or whatever..

i like supporting those who are actively working to support these products,,, without them alot of folks would not be in this game, and without alot of folks
there would be no game at all.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

Doug

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Re: ST power useless, Please assist me in improving the output!
« Reply #12 on: February 26, 2007, 11:06:50 PM »
Fair is fair Bob:

If you don't have the time or want the bother then by all means buy it.

I can make that part in as fast as it takes me rub a carbon rod on a piece of paper over the hole on an ST head, shear a chunk of scrap steel and punch the holes( I suspect with bridge in hand, set up time, and a coat of Glyptal baked on so its dry enought to handle and install 20 minuts ). 

If I were to spend a little more time and effort an Aluminum die cast box, the rectifier and perhaps even a large potentiometer and make a real nice replacement I could still do it under 29.00 USD.

As far as R&D are concerned, yes I'm all in favour of that, but a steel plate with a bridge screwed to it or a plate with a niple screwed in is a stretch for me to call R&D.

You get what you pay for.
I even make my own nuts, studs, fittings and in some cases even bolts, they cost a lot more than whats not sitting on a store shelf with a 2 week + delivery.
My time is my own and I'd like to think its better to invest ones time into a project than spend money and have it done for me.

Its all a matter of perspective.....


Doug

 

dkwflight

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Re: ST power useless, Please assist me in improving the output!
« Reply #13 on: February 26, 2007, 11:37:49 PM »
I bought my diode bridge at Radio Shack.
It wasn't 1000v but then the voltage on that circuit is around 48v on my ST head
Dennic

Mouser.com has similar bridge diodes for arounf $3/

Dennis
28/2 powersolutions JKSon -20k gen head
Still in devlopment for 24/7 operation, 77 hours running time

mobile_bob

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Re: ST power useless, Please assist me in improving the output!
« Reply #14 on: February 27, 2007, 12:25:44 AM »
Doug:

ok i will give you your point on research and development to make a further point.

say you can make these thing up for a cost of 5 bucks in parts and another 5 bucks in labor, that seems about fair

now you stock them so you can sell them,, and you tie up your money and labor anticipating sales, so there is a further
cost in cost of funds or interest.

now you get an order for one, and it takes you maybe another 15 minutes to box it up, gas to get it to the post office
or whatever,,

at the end of the day, i don't believe you could compete or rather would want to compete with utterpower on price.

also it is a fair point that utterpower not only needs to cover all costs, but make a profit!

so then the question might be, what is a reasonable profit??  i got an answer for that one to.
a reasonable profit has no calculation, in that price has nothing to do with cost!

price is what the market will bare, and really has no function or basis in cost.

then there are warranty issues as well, what if you sell a kit and the damn thing quits on the guy?
you get to send him another one for free, with shipping.. we all no that electronics fail, and cheap electronics fail often.

so you are left with trying to balance cost vs quality issues as well,, so as a supplier of a kit are you going to market a 3 dollar
radioshack bridge or a 10 dollar GE part or something somewhere between?
remember the supplier of the kit is not selling to licensed, bonded, skilled technicians, but rather DIY'ers who may or may not
have to skill to install properly, and kill it himself,,, then you are faced with sending out another for free or get bad press from
some joker who really has no clue in the first place.

at the end of the day, my bet is none of us could or would compete with utterpower on price of that kit and make out like a
bandit,, likely we would fall short and wonder why the hell am i selling these kits.

i would also like you to know that most of this diatribe is for everyones benefit, and i am not singleing out anyone.

further:

i like to do things myself as well, and i too have built some pretty cool stuff over the years, but after 32 years in my business i am very tired
of wrenching on anything and making a part that i can purchase doesn't have the appeal it once had.

perhaps when and if i can semi retire i will get the fire in my ass to build more of my own stuff, and i would assume at that point my time will be mine
and the value of which will be somewhat reduced.

an example is my offgrid place i plan to start building this year,, i would love to do it all myself, but i realize i can hire it done (at least the heavy stuff)
for far less than the cost of losing time in my business.

something like if you make 10 bucks an hour take home,, and you can find a willing person to do something for you for 3 bucks and hour and do as
good or probably a better job, would you still think it wise to do it yourself? in the analysis i am far better off to hire it done, it will be done adequately
and i will be dollars ahead. However i will not have the satisfaction of saying i built it myself,,, oh well, i have built enough crap for other folks it is time
for the circle to come around i guess.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info