Author Topic: how exact is exact? exactly  (Read 4757 times)

Mr X

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how exact is exact? exactly
« on: January 16, 2006, 12:52:55 AM »
Im wondering about pully size Im getting one machiened tomorrow. I have a 4k 3600 rpm winco The math works out to aproximatly exactly a ratio of 5.55-1 or a driven size of 4.25'' Giving me 3594 rpm at 650 on the prime mover. 10 rpm on the prime mover causes a in or decrease of 45 on the driven. This seams like a real sensitive ballance. With an engine screaming at 3600 a drop of 10 is nothing a drop of 45 still nothing. I guess what Im getting at is I have nothing to relate it to. That was pruven  today when I put a physical tack on the shaft and found it was running at 780 rpm I slowed it to 654 and it really smoothed out. I live at about 3000 feet bove sea level
So all ready a disadvantage.

Greg
« Last Edit: January 16, 2006, 12:56:26 AM by Mr X »
6/1 PS Jkson soon to run WVO,  3 hp Petter, 3 Honda 5 hp, 1 weed eater, Live off grid, Now a dog farmer

justsomeguy

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Re: how exact is exact? exactly
« Reply #1 on: January 16, 2006, 06:09:12 AM »
Disclaimers:

1)The Woodward 1712 or 1724 may cost more than the Lister.
2)I only know how well this governor works on high speed diesels.
3)I have absolutely no experience with this governor on a Lister, or any other slow speed engine where speed varies each time the cylinder fires ---- yeah, it'll see it speeding up and slowing down a few times a second, and try to compensate by moving the fuel rack between each power stroke if not set correctly!
4)It very well may be worth while contacting Woodward to see if this application would even work.  They've been in the governor business for a long time.

Ok, on to the post:

Want to be exact?  Obtain a Woodward 1712 Electronic Governor.  Most Caterpillar power systems dealers can order you one.   Or at least they can order all the "replacement parts" to make one, if they're not allowed to explicitly sell the whole packaged governor without a gen-set to go with it.

Here's how to adapt it to your Lister:

Put a sprocket on the generator pulley for the speed sensor pickup.  For 3600 RPM, you'll need roughly 72 teeth, but don't quote me on that.  The number of teeth are required to give that many pulses per revolution, so the governor can have that level granularity in it's sensing of speed.  Basically, it needs to make sensing readings many times per second so it can control fuel as fast as possible.  I think you can go with less teeth, but the governor won't be as precise, and won't respond as fast.

Disconnect the Lister's Governor.  Connect the fuel rack actuator to the Lister's fuel rack.  It'll be the sole fuel control.  No more futzing around with springs and adjusting it depending upon load to keep it close to 60 Hz.

The only other thing you'll need is a 12 (or 24) volt power supply for it. It'll draw about 4 (or 2 for the 24 volt) amps.  You can adjust it for droop or isochonous.  Droop operation is such that as speed drops, from say, 3600-3550 RPMs, fuel increases from 0 percent to 100 percent. Or you can set those numbers to your choosing.  Remotely, you could roughly estimate genset load by looking at Hz.  If you don't like Hz ever moving, you can set it as isochonous.  Isochonous operation keeps 3600 RPMs, all the time, no matter what, as long as the engine can put out ample horsepower.  If a load is applied, and the speed drops to 3595 RPMs for 2 seconds, the governor will pour on the fuel to 100%  to reach 3605 RPMs for 2 seconds (or 3610 for 1 sec, or 3620 for .5 sec)  to "catch up."  When it responds to a new load and the engine RPMs start to come back up, it'll even actually start to pull the throttle back before the speed ever comes up to 60Hz, as the 1712 (or 1724, for 24 volt operation) is fairly intelligent.   An isochonous governor will keep a an AC synchronous clock spot on, regardless of load from 0 to 100%.

With isochonous operation, you can not sense generator load remotely by looking at Hz, because average Hz won't move as load is added or removed.  It may drop or spike when loads are added or removed but will average back to 60Hz (or whatever you chose to set it at) within a few seconds, or less.  That's how the grid holds 60 Hz, no matter what the load.

For some reason, I find isochonous operation is amazing to watch (and hear)  as load is added and removed.  The Hz always reads 60, no matter what the load is.  The flip side is that it's a balancing act with engine response time, interta, governor gain setting, and the like.

-Jerry

Mr X

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Re: how exact is exact? exactly
« Reply #2 on: January 17, 2006, 12:55:09 AM »
Yes a detailed answer sounds pricey. I suppose tis a problem all us roid users have to endure even with a 4 pol head. My power is intende for use in my shop, with power to the house to charge batteries maybe a deepfrees or a pump directly off genny power for any thing sensitive I can invert

Greg
6/1 PS Jkson soon to run WVO,  3 hp Petter, 3 Honda 5 hp, 1 weed eater, Live off grid, Now a dog farmer

Classic Machine

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Re: how exact is exact? exactly
« Reply #3 on: January 18, 2006, 05:22:50 AM »
Greetings from New Zealand.  When using an electronic governor ALWAYS put the speed pickup on the prime mover, in this case the Lister.  If the speed pickup is watching the generator shaft speed and the drive belt breaks the governor will see zero or low speed and open the fuel rack to 100%.  The result of this will be engine failure.   

trigzy

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Re: how exact is exact? exactly
« Reply #4 on: January 18, 2006, 05:44:51 AM »
I hope someone didn't learn that lesson the hardway - didn't think of that.....  :o
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justsomeguy

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Re: how exact is exact? exactly
« Reply #5 on: January 28, 2006, 11:41:27 PM »
Ah yes.  Forgot about that.   ;D   On the gensets that I've worked on they use the engine flywheel, and put the pickup on that.  In that case though, the generator rotor is bolted right to the flywheel. Yes, te govoner should definatelyThe only requirement is that the flywheel has enough teeth moving past the pickup each minute.  144 tooth flywheel times 1800 revs/min = 259200 teeth per minute.  Or a signal of 4320 Hz.  There would have to be enough teeth on the flywheel of the Lister to provide a high enough frequency signal.  More teeth = more precise frequency control, and quicker response to load change.

n2toh

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Re: how exact is exact? exactly
« Reply #6 on: February 02, 2006, 09:51:39 AM »
anything smaller then a "female hair" is close enough.
About 60 years is all it takes to make science fiction a reality.

rgroves

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Re: how exact is exact? exactly
« Reply #7 on: February 02, 2006, 02:36:01 PM »
anything smaller then a "female hair" is close enough.

According to my dad-in-law,  in the oil patch that particular unit of measurement was broken down into three degrees.  Red was coarse, black was medium, and blue was exceedingly fine.
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