Author Topic: Pulsing power  (Read 5482 times)

westexx

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Pulsing power
« on: April 28, 2008, 01:54:36 AM »
 I have a 20 kw st head on a two cylinder ashwamegh. When powering the house I can see a slight pulse in the lights. I have checked all voltage and it looks to be fine (124 volts) on all legs. The meter is not showing and change. I have read somewhere that this is a problem with this type of engine. Is this something I will just have to live with or is there a way to correct it. Also will it damage any of my appliances.
Wesley   Ashwamegh 25/2

ronmar

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Re: Pulsing power
« Reply #1 on: April 28, 2008, 03:53:09 AM »
2 cylinder "flicker" should be less pronounced(1/2?) than that of a single cylinder, but yes, it will still be there. Even with one power stroke per revolution, there is still a little time between power strokes for the rotating machinery to coast/decelerate.  It dosn't typically show up on a meter, but you could see it with an Oscope.  About the only fix for this would be to add a Automatic Voltage Regulator.  This would make rapid small voltage changes and remove that pulsing you see in the lights.  I use predromenantly compact Florescent lights in my home, and they don't really show the flicker on my 6/1 except where I still use incandescants.  Having experimented with an AVR, I found it removes most all the flicker from a single and would probably do the same on a twin quite easilly.  An AVR would smooth out the voltage, but there will always be a small frequency change, but those are not really noticiable.  Even with flicker, my 6/1 powers all my electronics OK so far, and I even have 3 UPS's that it keeps on line.  I can't imagine 2 cylinder flicker causing you any problems.

Ron     
PS 6/1 - ST-5.

biobill

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Re: Pulsing power
« Reply #2 on: April 29, 2008, 02:49:54 PM »
 Don't the twins have a 180 degree crank? If so, the fireing would be 1/2 revolution apart and it would coast for a revolution and a half. Still some potential for RPM fluctuation I'd think.     Bill
Off grid since 1990
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carlb23

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Re: Pulsing power
« Reply #3 on: April 29, 2008, 04:06:20 PM »
Don't the twins have a 180 degree crank? If so, the fireing would be 1/2 revolution apart and it would coast for a revolution and a half. Still some potential for RPM fluctuation I'd think.     Bill

Not having a 12/2 I cant say for sure but while the crank is 180 degrees out, iit would be cams that determined what stroke it was on at that point.  I suspect that the power strokes are equally spaced.

oliver90owner

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Re: Pulsing power
« Reply #4 on: April 29, 2008, 04:51:18 PM »
carlb23 wrote: I suspect that the power strokes are equally spaced.

If the cranks are at 180 it must have unequal firing intervals.  There is no other option.  The cams have to be timed with the pistons and therefore with the crank.  Only with 360 cranks can you get equal firing intervals (the other option is both cylinders firing together!!!) with a two cylinder 4 stroke engine.  V block twins will vary with geometry. Horizontally opposed ..... now are they a v-twin with 180 between the cylinders?

Regards, RAB

ronmar

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Re: Pulsing power
« Reply #5 on: April 29, 2008, 07:11:07 PM »
Didn't even think about the geometry, Interesting...  If the pistons go up and down together, you could configure it for one power stroke per revolution. I don't think I have ever seen a twin crank.  I would think that if you were going to all the trouble of a 2 cylinder, you would configure it for one power stroke per revolution as this would be a smoother power delivery method.

Ron
PS 6/1 - ST-5.

Tom

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Re: Pulsing power
« Reply #6 on: April 29, 2008, 08:20:42 PM »
The problem with 360 deg cranks is that they require massive counter weights to offset both piston/rod assemblies.
Tom
2004 Ashwamegh 6/1 #217 - ST5 just over 3k hours.

ronmar

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Re: Pulsing power
« Reply #7 on: April 30, 2008, 12:45:32 AM »
And if that is the way the power is delivered, I would guess that the flicker on a twin will be about the same as that of a single as you don't have that much additional spinning mass.

Ron
PS 6/1 - ST-5.

oliver90owner

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Re: Pulsing power
« Reply #8 on: April 30, 2008, 11:32:07 PM »
Jens, you wrote: I had to go through all the positions to really believe this but yup, it's not even at all.

You only needed to turn your engine over slowly and watch the injection pumps for timings.  Odd that, but simple enough to overlook.

Regards, RAB

westexx

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Re: Pulsing power
« Reply #9 on: May 06, 2008, 03:20:57 AM »
 I just want to say thanks for the advice.
I have a  AVR on the gen head. I think it is working. It has the little adjustment on the front that will change the output voltage when it is adjusted up or down. I had to adjust it when I first cranked it up.
If this is not the correct AVR what can I do to fix this one or where can I get one that will solve the problem.
Wesley   Ashwamegh 25/2