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Author Topic: Peak output and flywheels  (Read 19315 times)

Doug

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Re: Peak output and flywheels
« Reply #15 on: August 13, 2006, 05:36:06 PM »
I was looking for a little patch of land with 12 foot of head and 2 cubic feet of water flow. I also came to the same conclusion that I would need to add at least 500 pounds of rotating mass 20 inches in diameter in order to slow the response to load changes enough to keep lights from flickering.

I still live in a "Burb", not too happy about it.

Doug

Jim Mc

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Re: Peak output and flywheels
« Reply #16 on: August 13, 2006, 07:00:25 PM »
Do you think a fero-resonat transformer would work? 

No.  Their output voltage varies if the frequency changes.  Any ones I've seen also run hot, so they waste some power.

GIII

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Re: Peak output and flywheels
« Reply #17 on: August 14, 2006, 01:55:40 AM »
Forgot about all that heat!!  Really bad idea.

mobile_bob

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Re: Peak output and flywheels
« Reply #18 on: August 14, 2006, 02:42:26 AM »
is having excess heat a bad thing? is it really a loss if it is inside your house in the winter? :)

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

GIII

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Re: Peak output and flywheels
« Reply #19 on: August 14, 2006, 03:36:57 AM »
You are correct, Bob.  It depends on where you stand, doesn't it?

Andre Blanchard

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Re: Peak output and flywheels
« Reply #20 on: August 14, 2006, 12:56:03 PM »
Thanks for the replies everyone.  However I still don't understand what good the huge flywheels are on a SOM if it has a 2.5kW head; it should be able to produce that much power continuously.  What am I missing?

I would guess that that 2.5 KW is the continuous rating, and like most any motor or generator peak output can be very much higher depending on the duration of the event.
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Andre' B

GuyFawkes

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Re: Peak output and flywheels
« Reply #21 on: August 14, 2006, 01:39:31 PM »
Thanks for the replies everyone.  However I still don't understand what good the huge flywheels are on a SOM if it has a 2.5kW head; it should be able to produce that much power continuously.  What am I missing?

I would guess that that 2.5 KW is the continuous rating, and like most any motor or generator peak output can be very much higher depending on the duration of the event.



Yes it is a continuous rating, as in 24/7 at full rated output, unity power factor.
--
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Rtqii

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Re: Peak output and flywheels
« Reply #22 on: August 14, 2006, 07:41:30 PM »
SOMs were made with 5/1s correct? So the engine was rated lower. I would assume (I know I know) that a 5/1 is different than a 6/1... And the kW rating of a 5/1 would be lower.

aqmxv

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Re: Peak output and flywheels
« Reply #23 on: August 14, 2006, 09:24:52 PM »
SOMs were made with 5/1s correct? So the engine was rated lower. I would assume (I know I know) that a 5/1 is different than a 6/1... And the kW rating of a 5/1 would be lower.

My understanding is that it was called a 5/1 for a while after the rated speed changed.  So it was 5 HP @ 600 RPM, or 6 HP @650.  Same engine.  The torque curve, btw, is pretty much a straight line in this range.

http://www.oldengine.org/members/diesel/Technical/51P4data.htm

6/1 Metro IDI for home trigen

Jim Mc

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Re: Peak output and flywheels
« Reply #24 on: August 15, 2006, 03:46:53 AM »
Listeroids can cause lights to flicker. The voltage climbs and drops in sync with the combustion stroke.

Speaking of flickering lights, there's another possible cure that some may favor (I'm rapidly learning to avoid using the word 'simple' on this forum - what's simple for some isn't for others).

Some Onan single cylinder Diesel sets had "flicker points" on them.  I've heard of it, but haven't looked at how they imlemented it.  My guess is that the points (like points on a pre-electronic ignition system) shorted across a field dropping resistor.  The points rode on the cam shaft, and were timed to close towards the end of the exhaust stroke, and open just past TDC on the power stroke.  That way, the field excitation current would be ramped up just as the engine speed was slowing down the most.


Rtqii

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Re: Peak output and flywheels
« Reply #25 on: August 15, 2006, 03:58:51 AM »
Listeroids can cause lights to flicker. The voltage climbs and drops in sync with the combustion stroke.

Speaking of flickering lights, there's another possible cure that some may favor (I'm rapidly learning to avoid using the word 'simple' on this forum - what's simple for some isn't for others).

Some Onan single cylinder Diesel sets had "flicker points" on them.  I've heard of it, but haven't looked at how they imlemented it.  My guess is that the points (like points on a pre-electronic ignition system) shorted across a field dropping resistor.  The points rode on the cam shaft, and were timed to close towards the end of the exhaust stroke, and open just past TDC on the power stroke.  That way, the field excitation current would be ramped up just as the engine speed was slowing down the most.

Another way that could be implemented would be with an ignition type capacitor instead of a field dropping resistor. When the capacitor closes it would boost the field.

Flicker is going to be seen as a result of both a drop in frequency and voltage... This is not going to help the frequency sag, but with a small voltage boost at the right time most of the flicker could be eliminated so that it would not fatigue the eyes.

Jim Mc

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Re: Peak output and flywheels
« Reply #26 on: August 15, 2006, 04:07:43 AM »
Ignition type capacitor?  You mean the little .1 uF caps used in distributors?  That would not be large enough to boost the field supply significantly.

The field draws around 2A, and it needs to be boosted for 1/2 of an engine revolution - about 1/40 s at 600 rpm,  That will require many 1000's of uF's.

If we keep the voltage constant, how would a drop in frequency cause visible flicker in an incandescent light?





Rtqii

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Re: Peak output and flywheels
« Reply #27 on: August 15, 2006, 06:00:08 AM »
Ignition type capacitor?  You mean the little .1 uF caps used in distributors?  That would not be large enough to boost the field supply significantly.

The field draws around 2A, and it needs to be boosted for 1/2 of an engine revolution - about 1/40 s at 600 rpm,  That will require many 1000's of uF's.

If we keep the voltage constant, how would a drop in frequency cause visible flicker in an incandescent light?

I said type, I did not specify size really... And it will work and it won't require many 1000's of uF's. The capacitance cancels some inductance in the field winding, it does not make much difference how long it stays in the circuit it's job here is not to deliver a pulse of energy but to continiously cancel winding inductance and increase current flow. As far as size goes, you might need something between a standard ignition capacitor and a motor start capacitor... But it's not going to take something huge. I have seen big ignition type capacitors for aftermarket/performance/race coils back in the 60's and 70's that I think would work fine. Same type, same construction, same voltage rating would work here... You would have to play with the size because too big of one will cause surges in place of your drops.

As for voltage/frequency drops in lighting applications: When you have flicker you are seeing the voltage drop because the frequency is lagging during portions of the engine cycle. If you engineer a solution to boost the field voltage during this portion of the cycle, as we have been discussing, the visible flicker is resolved, what remains unresolved is the frequency sag... The energy looks smooth to the eye, and the eye will not resolve the frequency lag in lighting applications... Good enough for government work, but in a power processing research application such as I intend to run, frequency sagging is unacceptable.

I intend to put high energy physics loads on my equipment. Some drift is acceptable (such as rack changes to accomodate loads), but sagging during engine cycles, every cycle, is going to give me headaches. The other problem with the type equipment I run is that it is even harder to load up than say dropping an air compressor motor and an arc welder on at the same time... Huge inductor masses (in fact I have loaded shorted out arc welders on as ballast)...

I need clean, stiff, energy out of a system that would want to drag the engine around by the nose.

I will post some pics, then you will understand better.

Rtqii

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Re: Peak output and flywheels
« Reply #28 on: August 15, 2006, 07:55:27 AM »
http://listerengine.com/coppermine/displayimage.php?album=101&pos=2

^^^ Preamp

If you are processing raw power into a power amplifier, frequency sags are propagated thru the system and are amplified as well... The result is distorted output, exactly like the distortion seen/heard in audio amps when either the input signal is not clean, or the amp is clipping. In this instance, you could actually document frequency sagging with the naked eye if you used a one second exposure of the test arc... And as you amplify the pre-amp output, the distortion just gets more pronounced.

http://listerengine.com/coppermine/displayimage.php?album=101&pos=3

^^^ Hard starting load - This is another preamp configuration... Energizing the cores on these loads stalls the engine on a 5 HP gas generator when you throw the switch.

http://listerengine.com/coppermine/displayimage.php?album=96&pos=1

^^^ Frequency stability and load starting. This is my working design for an 1800 RPM jackshaft with steel flywheels. The shaft would be belt driven from the engine, and the generator would be direct coupled to one shaft end. The flywheel mass and higher rate of rotation should really improve the "flicker" quality of the input signal and provide torque on demand at a high rate of delivery to energize my physics loads.

http://listerengine.com/smf/index.php?topic=634.msg8830#msg8830

^^^ Interesting post noting the effect of poor waveform on microwave ovens...
« Last Edit: August 15, 2006, 08:03:29 PM by Rtqii »

Doug

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Re: Peak output and flywheels
« Reply #29 on: August 16, 2006, 12:04:09 AM »
I don't remeber anything like this on the CK CCK or the 3600 rpm engines....

I think you just turned on your lights and smiled. They were good plants.

Doug