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Messages - mjn

Pages: [1] 2 3 ... 8
1
Changfa Engines / Re: Changfa saves the day
« on: February 26, 2010, 07:25:25 PM »
...
Are you feeding a battery bank? or is the ST7 connected directly to a transfer switch ?

The generator is connected via a transfer switch. After starting the generator, I throw the switch which disconnects the house from the utility and connects it to the generator. Other than careful power management when running the dryer, we can use any electric appliance we like. The only thing I need to fix is that I have no indication of when utility power returns. (We have to look out the windows to see if the neighbors have lights on.)

Still waiting for my first power outage, at least one long enough to count. May I also mention mjn's website http://sites.google.com/site/martinnile/ it is a must read. I have learned a lot from you guys who have taken the time to document your experiences with these power plants. Thank you.

Thanks for the the kind words. My whole purpose in building the website was to give back some of what I had learned from others on the net.

--
Martin

2
Changfa Engines / Changfa saves the day
« on: January 27, 2010, 11:29:06 PM »
Last week, my community in Northern California got hammered with 50 inches of wet sticky snow. By the end of the storm, 9000 people were without power. Pacific power had a huge job cleaning up the mess. Nearly every power pole had some sort of problem. The snow was so heavy that if the wires didn't break, the weight sheared off the cross arms. Trees that had stood for hundreds of years collapsed (usually taking out a power line).

Fortunately, I was ready with the Changfa 195 and ST gen head. I had the boys shovel out a trail to the generator shed that morning. When the power went out, the Changfa fired right up and took over the job of running the lights and the pump in the well.

Previously, the Changfa was a noisy smelly beast that was merely tolerated by my wife. All of a sudden, the ugly duckling became a sweet smelling shining beauty. She invited all of her friends to come bask in the glory of electric lights and running water.

For many people, the power outage lasted for 5 or 6 days. Our power was out for about 30 hours. The Changfa ran for 22 hours and burned about 10 gallons of diesel. This time of year, the veggie oil is all frozen, so I didn't try to thaw it out.

The sad epilogue to this outage is that in our small mountain town, there were 11 people admitted to the hospital for treatment of carbon monoxide poisoning from their gasoline powered generators. Many people ran their generators in closed garages, or even a basement. One man died even though his generator was away from his house, the CO was trapped between the walls of snow and flowed back into his house.


3
Listeroid Engines / Re: autostart on chinese diesel
« on: January 05, 2009, 07:15:34 PM »
...snip...
Anyone know what type of throttle actuator solenoid to buy??


The Murphy RP2307B solenoid is designed to do exactly that.


Murcal has these available for $54 http://shopping.murcal.com/Catalog/Rack-Pullers/RP2307B-Push-Pull-Solenoid


The ECU-05 has an output that can be used to momentarily pull the rack closed to kill the engine.   On my Changfa 195, the best place to install this is directly on the governor fork where it meets the injector pump. 


In this picture, the fuel limiting adjuster has been removed. The green line points to the governor fork.  Pressing in on the fork will close the injector pump and kill the engine.  On my engine, the fuel limiting adjuster is useless, so eliminating it is not a problem.



4
Listeroid Engines / Re: autostart on chinese diesel
« on: December 18, 2008, 05:10:37 PM »
I have no idea what this costs, but this controller from fw-murphy looks like it will do the job:


You can read about it at:
http://www.fwmurphy.com/products/engine_motor/asm170.htm

--update--
I found a place that sells it for $375 ..
http://shopping.murcal.com/Catalog/Automatic-Engine-Controllers/ASM170-A99069-Auto-Start-Module
--
Martin


5
Listeroid Engines / Re: autostart on chinese diesel
« on: December 17, 2008, 11:11:54 PM »
Hi Kelly,

I've built an autostart controller for my Changfa 195.  You can read about it at http://martin.nile.googlepages.com/automaticgeneratorcontroller

Unless you are really handy with a wire-wrap tool and programming, you are probably better off with a $200 commercial product.

--
Martin

6
Lister Based Generators / Re: automatic frequency control, revisited
« on: October 27, 2008, 04:59:58 PM »
Do you have any interest in providing a unit like this for the group here? I would guess that there would be a few takers. I would be interested in purchasing one if the price was right. Obviously, I can build this type of thing myself, but if someone else has already worked out the bugs, well then......

I can't promise to have one working very soon.  I expect that this will be my project this winter.  Unfortunately, I won't be able to test it on my listeroid until after the last freezing temperatures next spring. When I get it working, I'd be glad to provide schematics and source code. 

MJN , I like that system !! The irony that occurs to me is the sheer complexity of electronics required to exceed the function of a coil spring !!

JUst a thought , how about a linear actuator instead of a stepper motor ?
Yeah, it seems like overkill having a 16mhz cpu just to do the function of a simple spring.  The spring is in reality a "P" (proportional) controller.  It would be a real trick to add the "I" (integral) and "D" (Derivative) functions with a purely mechanical solution.

The linear actuator was one of my options when I was working on my design.   I ran into a good deal on my stepper motor assembly, so that helped set the design.   Also, I already had the correct MOSFETs for driving a unipolar stepper.  I would have had to buy more stuff to build the H-Bridge necessary for a linear actuator.  Personally, I like the accuracy of a stepper motor.  The additional code needed to drive a stepper motor was not that bad.

What is happening to the voltage during these rpm changes?
I don't have the exact voltages, but from experience I would estimate that the low end, the voltage would be around 115 volts for about a second, and would peak at 125 for half a second or so.  An AVR would probably keep these under control.

--
Martin

7
Lister Based Generators / Re: automatic frequency control, revisited
« on: October 24, 2008, 11:12:08 PM »
Chris,

I have built exactly what you are thinking about.  It works fine.  My biggest mistake was to add too many bells and whistles.  I would have been better off with just controlling the frequency, I ended up with a system that does everything except feed the cat.  You can read the whole story here: http://martin.nile.googlepages.com/automaticgeneratorcontroller.

As Jens pointed out, the trickiest part of building a PID controller is tuning the gain variables.  Mine is not perfect,  There is room for improvement.  I stopped tweaking when I got it to hold the frequency close enough to keep my APC ups happy.  I'm doing this with a Changfa 195 running at 1800rpm.  I haven't tried this on my listeroid. I assume it would take longer for the PID controller to catch any frequency excursions.

Here is a graph that shows how my controller behaves versus the stock spring.



When I add a 5000 watt load, the stock governor (purple line) drops to 1700 rpm (56.6hz) within half a second.  The PID governor starts picking up at .4 seconds and has recovered to 1800 rpm by 3 seconds.

This graph shows the behavior when the load is removed.


The spring governor behaves nicely and the rpm's return to 1800 within about a second.  The PID controller overshoots the mark by 60rpm (62 hz) but eventually settles to around 1800rpm within 1.5 seconds.

For your reading enjoyment, here is my fixed point implementation of the PID controller.
Code: [Select]
/*******************************************************
 * pidcontroller -- calculate the adjustment to the stepper position
 *
 * based on emprical tests: Pc=20, Kc=280
 *
 * Ziegler-Nichols tuning: pgain=0.65 * Kc  = 182
 *                               Ti=0.5 * Pc = 10
 *                              Td=0.12 * Pc = 2.4
 *                         dgain= pgain*Td = 182*2.4=436
 *                         igain= pgain/Ti = 18 *4 = 72
  * All gain values are multiplied by 256 so we can do
 * the arithmetic in integers.  The result is divided by 256
 *
 ******************************************************/
int pidcontroller(void) {
int error;
long pterm; // proportional term.  The pterm is long because on startup
// the pterm has a very large error when multiplied by the pgain
// will exceed the size of a normal int.
int iterm; // integral term
int dterm; // derivative term

int temp;


#ifdef PIDTUNE
pgain=(getadc10(3)-8)*2; // pc3 (uco empty) is temporarily used as a pgain control
if(pgain < 0) pgain=0;
igain=getadc(4)-8; // pc4 (diesel empty) is used as igain control
if(igain < 0) igain = 0;
dgain=(getadc10(1)-8)*4; // pc1 (watertemp) is dgain control
if(dgain < 0) dgain = 0;
#endif


error=TARGETRPM-rpm;

// calculate the proportional portion
pterm=((long)error*pgain);


// calculate the integral portion
// If we are at the stepper limit, and still want to go higher,
// do not add any more to the integral
if(!(PINB & LIMITHI) && pterm > 0) {
temp=sumerror;
}
else {
temp = sumerror + error;
}

if(temp > 5000){ // limit the integral windup
temp=5000;
}
else if(temp < -5000){
  temp=-5000;
}

sumerror = temp;
iterm = (igain * sumerror)/32; // note!! /32 gives us more fractional resolution for the igain variable

// Calculate the derivative portion
dterm = dgain *  (rpm - lastrpm);
lastrpm = rpm;

temp = (pterm + iterm + dterm) / 256;

// if the adjustment is less than 2 steps, don't bother
if(abs(temp) < 2) {
temp=0;
}

#ifdef PIDTUNE
putstr("\r\n");
print4(rpm);
putch(' ');
print3(pgain);
putch(' ');
print3(igain);
putch(' ');
print3(dgain);
putch(' ');
print5(temp);
#endif
return(temp);
}


I have been kicking around the idea of building a minimal frequency controller without all of the bells and whistles of my generator controller.  I'm thinking of using an 8 pin MCU and the guts of an old 5 1/4" floppy drive to apply a bias to the stock governor spring.  Total out of pocket expense should be less than 10 bucks for the CPU and hall effect sensor to pick up rpm.  Everything else is sitting in my junk box.

My Listeroid has had all of the water drained and buttoned up for the winter, so I won't be able to do any testing until sometime next year.

--
Martin


8
Generators / Re: Help with oscillating governor
« on: August 01, 2008, 05:15:08 PM »
A quick look at your website shows an amazing project indeed!  Must study this in some detail.  Just a word of caution from a Changfa and Jiang-Dong owner.  I'd worry about engine vibration work hardening and breaking the tiny wires on the microswitch and other contacts which are engine mounted.  At the very least a dab of RTV silicone at these joints is your friend.  The wire adjacent to the solder joint will take more flexing than the joint itself.

Thanks for the great suggestion!! I've already had to fix one of those wires once.  I think the RTV should do the trick.

--
Martin

9
Generators / Re: Help with oscillating governor
« on: July 18, 2008, 06:18:19 PM »
I know RAB was speaking somewhat tongue in cheek, but for the computer geeks, out there, it has been done.   My cpu (ATMega8) only cost $5.00 (including a/d converters and all).  That was the cheapest part of the whole thing.  You probably won't be able to get a stepper motor and leadscrew for anything less than $100.

To save you the grief of writing a PID controller.  Here you go free of charge...
Code: [Select]

error=TARGETRPM-rpm;

// calculate the proportional portion
pterm=((long)error*pgain);


// calculate the integral portion
// If we are at the stepper limit, and still want to go higher,
// do not add any more to the integral
if(!(PINB & LIMITHI) && pterm > 0) {
temp=sumerror;
}
else {
temp = sumerror + error;
}

if(temp > 5000){ // limit the integral windup
temp=5000;
}
else if(temp < -5000){
  temp=-5000;
}

sumerror = temp;
iterm = (igain * sumerror)/32; // note!! /32 gives us more fractional resolution for the igain variable

// Calculate the derivative portion
dterm = dgain *  (rpm - lastrpm);
lastrpm = rpm;

governorcorrection = (pterm + iterm + dterm) / 256;

That was the easy part, the hard part comes in tuning the gain variables.  These will be different for each and every system. Unless you want the fun of learning how to build a controller and program it, I don't suggest you do it.  You are better off experimenting with different springs until the oscillation goes away.

If you want to see how I built my controller, go to http://martin.nile.googlepages.com/automaticgeneratorcontroller.  Source code can be had at http://code.google.com/p/ngencontrol/

To show how my controller behaves, this graph shows the stock governor (purple line) versus PID governor (green line) when the engine load goes from zero to 5000 watts.


Note, it is normal for any P type governor (such as a spring) to exhibit "sag", or oscillation when load is applied.  You can minimize the sag by increasing gain (using a stronger spring). The system starts to exhibit oscillation when the gain gets too high.  In your case, you can minimize the oscillation with a weaker spring, but at the cost of having the RPM drop when load is applied.

My controller is great.  Unfortunately, I haven't figured out how to use a computer to make my Changfa any quieter.

10
There is no need to put a thermostat on your fattywagons heater.  As long as you are running fuel through the line, the heater won't get too hot.  When I first installed my heater, I could only get 65ºC at the injector, so I added insulation to keep the heat loss to a minimum.

On my Changfa,  I'm powering my fattywagons heater it with unregulated a/c (~16vac) from the battery charging alternator. I am getting from 80º to 100ºC at the injector depending upon the load. 

On my Metro Listeroid, my Fattywagons heater is powered by regulated 14 VDC, and I am seeing at most 80ºC at the injector.  I also insulate the injector line to keep heat loss to a minimum.

11
Everything else / Non electric overheat/overspeed shutdown
« on: April 01, 2008, 07:22:10 PM »
I have developed a revolutionary new concept for emergency shutdown of a Lister type diesel engine.  The device can be constructed from materials at hand for mere cents.
 
Functional Parts
   1. Smelly Cheese sitting on engine
   2. Mouse Attracted to smelly cheese
   3. Cat attraced to mouse attracted to smelly cheese
   4. Dog sleeping
   5. Old boot attached via string to shutoff lever of engine

Setup
  1. A piece of smelly cheese is placed on the rocker arm cover of the engine. 
  2. This in turn attracts a mouse to the engine, but due to the fact that all properly maintained listeroid engines develop a protective covering of oil and grease, the mouse is unable to climb up and get the cheese. The mouse sets up housekeeping nearby.
  3. A cat is attracted by the presence of the mouse, and sets up camp to get the mouse.
  4. A dog is kept nearby because federal law requires that cats need a dog nearby to keep them honest.
  5. A boot is attached via string to the shutoff lever of the engine.

Operation

   1. In the event of engine overheat, the cheese will begin to melt and run down the engine.
   2. The mouse, seeing his chance will come out of his hole and start eating the cheese.
   3. The cat seeing the mouse, tries to catch it.  It is a well known fact that anything within shouting distance of a properly maintained Listeroid will become covered with oil.  The mouse, having lived near the engine has a protective covering of oil which prevents the cat from catching the mouse.
   4. The cat after having been robbed of a tasty meal of mouse, begins to caterwaul bemoaning his loss.
   5. The dog after having been rudely awakened from a nap begins to bark at the cat telling him to "shut up".
   6. The wife or neighbor upon hearing the ruckus picks up a boot and heaves it at the nearest offender.
   7. The string attached to the boot pulls the cutoff lever and shuts down the engine.

The operation in the case of overspeed is similar except that the vibrations of the engine will shake the cheese so that it falls off and the procedure begins at step 2 above.

April 1, 2008 Martin Nile

12
Other Slow Speed Diesels / Re: Changfa Radiator - And Alternator
« on: February 21, 2008, 06:19:08 PM »
Veggie and I have been conversing in the background.  I'll post this here so everybody has the same information.

There is a mistake in the Changfa manual.  I faithfully hooked up my electrics according to the book and managed to cook a battery by feeding it unregulated, unrectified A/C.

Here is a scan from the Changfa manual with a red circle on the error.


Here is my corrected version of the Changfa manual.  Blue indicates an optional connection
for more current.  I added red and green to clarify what wires are connected to the regulator


Finally, here is my own schematic of the same thing.


I hope this helps others avoid problems when they are hooking up their electrics.

--
Martin

13
Listeroid Engines / Re: Residential Silencer - Underground !
« on: February 19, 2008, 04:56:06 PM »
In addition to dealing with the exhaust noise, you will need to muffle the intake as well.  My Changfa makes nearly as much noise on the intake as the exhaust.   Once you get the intake and exhaust quieted down, then you can work on getting the mechanical clatter silenced.

14
Other Slow Speed Diesels / Re: Waste Veggie Oil
« on: February 13, 2008, 05:11:26 PM »
I have about 200 hours on my Changfa running filtered and dewatered WVO.  I haven't pulled the head, but I do a compression check with every oil change.  So far, the compression checks show no loss of compression (which would indicate ring coking). I'm sure there are others who have more hours.

When I first looked into running WVO in a generator, some "experts" claimed that the engine would coke up within a few hours on WVO because of the constant rpm characteristics of running a generator.  At the time, it was felt that you needed to rev the engine to clean out the carbon.

About that time, John from Fattywagons reported good results using electrically heated injector lines.  Ken Gardner running a 6/1 listeroid reported significant decrease in coking when running injector line heaters.   That convinced me that heating the injector line was a good thing.

In my opinion, the hotter the better when it comes to WVO.  I'm typically running between 80º and 110ºC at the injector.  I have heard of people running as hot as 150ºC (300ºF).

In case you are interested, I'm using this compression tester from harbor freight http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93644  It cost a whopping $25.  Unfortunately, I needed to machine an adapter to fit the Changfa head.  (Made from a 12mm metric bolt.)

15
Other Slow Speed Diesels / Re: r195 changfa lowest speed
« on: October 02, 2007, 05:45:45 PM »
Back when I was working on my computer controller for my 195, I picked 600 rpm to warm up the engine after starting.  When running at 600 rpm, the engine hammers quite a bit.  When I upped the speed to 1000 rpm, it seemed to smooth out and not put so much load on the lovejoy connector.

I haven't tried to see how much power I can get out of it at that speed, but 1000 RPM seems to be the lowest reasonable speed for this engine.   A larger flywheel like rcavictim has will probably make a huge difference.  (The flywheel on my 195 probably weighs 1/4  of what one of the flywheels on my 6/1 metro weighs.)

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