Richland's Homebuilt Mill/pictures/first cut!!!

[Flurida_BlackCreek]

That mechanics reasoning is flawed. If you could control the rotor current on both alternators with one regulator I don't see any reason why it wouldn't work.  To use internally regulated alternators you would have to remove(disconnect) the regulator in one and connect the rectified dc currents together and allow the regulator to activate both rotors. Otherwise you wont get very many amps charge, they will nullify each other thinking the battery(ies) is/are charged.  Alternators work like power on demand, so to speak, they only put out extra juice (amps) when they are needed, ie. a 100amp alternator won't always put out 100amps, If they did they could cook your battery, and they do this by sensing the battery and load conditions and increasing power to magnatize the rotor. The stator is what makes the difference in how many amps the the alternator can put out without burning out the windings. If you used two non IR alternators, a diode inline on each( to keep from back feeding) and one regulator like Modat stated it should work without having to internally modify the alternators. Clear as mud?

[RichlandSawyer]

Actually  that makes perfect sense. Now all i have to do is figure out how to disconnect the charging system from the motor. Or use a seperate battery for the 12vdc motors. Lots to think about. Thanks fellars i knew you would come though for me.

Tom, I have raised bunks that come up to 1 inch from the blade. The reason for the extra sheet metal was to allow larger bandwheels if someday i felt the need. Not knowing much about bandmills i figured i'd leave that option open. Of course the bunks would have to be modified but that would be much easier than building a new blade guard. Also in the picture of the bunks you'll notice that they are two pieces of tubing. The bottom one is three inches and the top is one inch the reason for this is added strength and if they start to show wear like dents from rolling large logs i can just replace the top one inch piece. Thats my frugal side shinning through.

[Tom]

Perhaps the blade guard goes to the side of the bunks.  It looked, in the picture, as if the sheet metal of the shroud would hit the bunk.

[RichlandSawyer]

Thats correct it clears by uuuummm i think about an inch on either side. I also figured the raised bunks would be handy for loading logs with forks on the tractor. The temperature was 94 today and the weather man says saturdays high is gonna be 68 so i should be able to get some more welding done and maybe throw another log on and have a go cutting. The boys and i have been hanging around the pool on these hot days. Hard to convince myself to get all dressed up to do any welding  when its this hot.

[Tom]

I'm having the same challenges.  It's been 95 or better here, much higher than the weather man says.  I have trouble in staying interested in anything outside. :D

[jpgreen]

Hmmm... I'm not so sure I believe 2 alternators will nullify or cancel each other out.  They see battery voltage, and if the voltage is below the threshold they will both kick on and charge.

When the voltage is up, the regulators will kick in. You simply will have more charging power to the battery, and thats all.

If you have 100 amps output on one alt, and 20 on the other, you have 120 amps to the battery while operating.  If you need that much, they will produce it.  If you don't they won't it's a simple as that.

As soon as you put a load on the battery, and the voltage drops, the alts kick on.  If you sucked 100 amps off the system through the battery, they kick on and charge.  They won't fool each other.

If they "sense" each other, by means of sensing voltage and the voltage is high enough where they stop output, that means you didn't need it anyway. You're not drawing enough from the system.

The only difference could be where they had the threshold set on their individual regulators.  One my be set to shut off charging when the battery reached say 13 volts, whereas the other may be set to shut down at 13.5, or 14volts.

This means one may charge a little longer than the other. 

As soon as you run your mill, and it starts sucking amps off the battery, the voltage drops.  As soon as it drops to 14,13,12, 10, 9 etc. that DC voltage drops below the threshold setting on the regulators... they read that lower voltage and kick on.

................. 8)

[woodbowl]

  They see battery voltage ......

If you have 100 amps output on one alt, and 20 on the other, you have 120 amps to the battery while operating. 

If you sucked 100 amps off the system through the battery, they kick on and charge.  They won't fool each other.

If they don't fool each other, I'm assuming that each alt. has it's own independant wire to charge the battery.

Scenario #1. -
What is the outcome, if both alternator wires are located at two different points on the battery terminal .... VS .... crimped together and located at one point on the battery terminal?

Scenario #2. -
What is the outcome, if both alternator wires are connected together, then a single wire is connected to the battery terminal?

    (2 Delco Remis with internal regulators)

[joelmar10]

Scenario 1:  there would be no electrical difference between crimping together or separate connections to the battery terminal.  they would be connected in parallel to each other either way.

Scenario 2:  are you saying they would be connected in series?  I believe if that is the case whichever alternator kicks in quickest, that would be the only one charging?  since 14.3v (or whatever the charging voltage is from the first) will be sensed by the regulator on the slower one (slower by fractions of a second).  seems to me you'll have a backup alternator that is only wearing it's bearings out.

Either that or since they both clip an ac wave to make dc they might battle it out, if the dc voltage isn't smooth, since the little dips in voltage would be out of sync.  But it would have to be a big dip in voltage!!!!  As unlikely as that scenario is, i think that the "battle" would only smooth the dc voltage in the system.

being so far apart in amperage adds a twist to loading, but I think having them both connected in series to the battery would be fine.

am i thinking correctly on this?

[jpgreen]

Connecting the alternators in parallel to charge is the best way to deliver the most Amps to the batteries.

If the two alternators, each with their own regulator, are connected in parallel, the regulator with the lowest threshold (or setpoint) will quit charging when the other alternator can supply all the current required by the battery and load.

Threshsold is an audio record engineering term, and that's why I was using it, but setpoint would be a better term for this application.

You can run a single regulator to drive both alternators, both alternators will then share the load at the same time and deliver according to their rating and their RPM, but a single regulator is not absolutely necessary in our application I believe.

I'm going to work on this, and set up a diagram with fuses, since I have to do the same thing on my LT40.  My Kawasaki engine has a 25 amp alt, and I'm also installing a 87 amp Delco.

................... 8) 8)

[Tom]

Here is just a thought.  I don't know what I'm talking about so take this with a grain of salt.

One of the failures on a sawmill that seems to stop you in the middle of the most important job is the alternator.  They can be rebuilt but, unless you have a spare, you are dead in the water for at least the rest of the day.

Why couldn't you keep the internal alternator in reserve for a backup, just in case it was ever needed.   I know they aren't large enough to keep the battery up in heavy sawing, but, one could be used to limp along while some else took the big alternator to the shop for a rebuild.

Can't the internal alternator be "not used" and save its wear and tear?   Or, is it going to wear out whether you use it or not?

[jpgreen]

Pretty much going to wear and tear anyways.

[jpgreen]

OK- after some more brainstorming in regards to our application, both alternators wired together in parallel will charge together with no problems when the engine is running.

Each alternator will regulate according to it's setpoint.

One problem is when the engine is not running, voltage can backfeed (from the battery) to the alternators, and drain the battery some. One way to fix this is to install one way diodes between each alt sized according to their amp ratings.

They other way to fix this is to install a battery switch- sized to handle your total amps, between the alt outputs and positive side of the battery.

When your engine is not going to be running for an extended period, turn the switch off.

Since we are not running the same sized alternators, I don't thing using a single regulator would be a good idea.  They aren't going to be sharing the same amperage out put.

I think parallel wiring and simple switch is the best solution..  8)

[jpgreen]

...or just disconnect the battery cable when you're done for the day..  ;D

It may not even drain that much.  Disconnect the battery cable when you go on vacation, or during a blizzard, or..  :D

[RichlandSawyer]

Here is what i've come up with. According to everything i've read you cant parallel alternators without a special controller.
And you are correct JP we will need a relay to disconnect the alternator from the battery when the engine is not running.

I'm still searching for more info.I cant seem to find specifics on what happens when they are parallel they just say dont do it. The 4x4 guys say you can do it in an emergency. No one states the ill effects.

[jpgreen]

You won't find any info on specifics to what damage happens cause there is none.

I just confirmed it with a guy I know who's in business to charge batteries with solar wind and any kind of generator you could think of, and has been doing it for over 25 years.

The only problem there could be is if you mount a tachometer to your alternator, like I do on my diesel pickup. It will not read accurately.  If there is a computer electrical system like on our new cars and trucks, that would most likely also create a problem somewhere, but to run our engines on sawmills is not going to be a problem.

As I mentioned above, these alts are not real complicated.  They simply turn on and off based on the 12volt DC voltage level. As soon as the voltage drops below 14v, they are both going to work.  As soon as the voltage gets back up, and that depends on how much draw the mill uses, ones gonna shut off slightly sooner.

With my solar system the main thing is to get batteries refilled, and recharged as quickly as possible.  If that means hitting it with 3 chargers fine. But, my favorite by far is DC charging, direct to the battery bank as we're talking about here.  I charge my system with Delco DC, even though I can hit it with the charger in my Trace 4500 watt inverter- that has a huge AC battery charger in it. Sometimes I hit the batts with both AC and DC. 

The DC allows you to continually take big amps off of your system, and it will smoothly replace them without a hiccup.  So I can run my shop equipment whilst my solar panels are filling the gap, and at the same time (only if I'm running heavy) I run a Delco Alternator with a little diesel engine.

Like refilling a water cooler as you drink from it.  That's what we need.

I'm gonna run both alts on the Kawa-Miser this week, so if it blows I'll let you know.. ;D

[Flurida_BlackCreek]

Not much to wear and tear on most of the small engine internal alternators. They work like a pm motor, as long as the windings don't get burnt out they will work forever. The draw back is the low amps. The rectifiers, diodes and regulator can go bad but they will still produce ac currect.

I'd hook the 20amp internal alternator to a small cranking battery, and use a 100amp 12si or 27si alternator to charge 2 deepcycle batteries. The aux alt can be activated by the key switch and no relay would be needed, just connect the field activation lead from the regulator to the accesory lug.


Why it won't work in parallel with two regulators is that when one is charging and putting out 14.7volts+-the otherone will "think" the battery state is full, one nullifies the other. If you disable the ability of either regulator to regulate the voltage to the rotor(which is what it actually regulates and inturn determines the output of the alternatror) and apply full voltage to the rotor it will put out full amps and either cook or blow up your batteries or burn itself out. Don't do it. I've never seen one but that controller can't be to much of a big deal just a few diodes, maybe a relay and a ic regulator.

JP ask him what he does for dump loads?

[jpgreen]

OK-

I just poured through my LT40 scematics, and THEY have one heavy BATT wire running from the Delco external alternator output to the starter solenoid on the the engine.  AT this point the 2 alternators are paralleled.

From the starter solenoid runs the same heavy wire to a 100 amp fuse in the LT40 fuse boxe with the flat metal fueses.

A small yeller wire is running from the Delco field tab to an alternator light, then on to the "Key On" side of the ignition.

I respectfully disagree that the one alt will see 14.7volts from the other get fooled then shut down. Maybe for a brief instant it will see that voltage, but what the whole circiut is going to see is the battery voltage, and that is what will trigger the regulators on each alternator.

One alternator will work a little harder than the other at times, but when the load of the hydraulics is hammered down on the battery, both alternators are going to kick in full tilt, until the battery voltage reaches the top fill point, and setpoint on the regulators.

.................................... 8) 8) 8)

[red]

there was a BMW  about 1990  that had  dual alternators

it was the real big 4 door might have had dual A/C  comp  too

i dont know of any other cars ....   but  why not  use dual batteries ? 

[joelmar10]

JP.

Yer right that it's not a problem to have two in parallel.  However...

I'm perty sure that in a parallel circuit their share of the load would still be determined by whether or not the one with the higher charge voltage (all regulators are not equal) can carry the current load and maintain a steady voltage. The charging alternator's generated voltage BECOMES the battery voltage and the battery becomes a load.  All legs of a parallel circuit drop or "sense" the same voltage and the battery is in the same parallel circuit.  The one with the higher charge voltage would stay on and the second wouldn't turn on until the first one's maxed out and system voltage drops or a large transient like a surge load occurs and the "system" voltage momentarily drops to the second one's kick-in point.   And since current is added in a parallel setup (Kirchoff's Law---- btw, where's Norm on this?!? He's an ET...)you will have 120A total alternator capacity.  Also, each alternator needs to be independently fused on it's leg according to its rated output.

Clear as mud?   

But like Flurida, I'd go with two circuits just the same.  Deep cycle on the other loads for surge capacity and for fewer shorted cells over time.   All it takes is one oil-and-dust-goo short to frame or a heavy discharge and a cell or two will short with those wimpy little plates on a starter battery. 

Of course I'm probably the only one here who lets their stuff get dirty enuff to short.  ;D


 

[jpgreen]

Well time will tell, because I'm going to get to the bottom of it.

Wood-Mizer has been running LT40's that way for many years.  ???..  ;D

[iain]

I dont know if it will help, but when we slung the new kohler onto the lt40hd, it has its own internal charger that dont do much (about 4amp i think),

so a newish) 110amp from a Citroen (looked all shiny and sparkly)was bolted to the pulley side and connected to the battery (biggest i could fit in the box) using the wm big cable everything has worked for yonks now




Iain

[jpgreen]

That's right see..  :D

2 alternators hooked up with their own regulators in parallel, and has worked for Yonks.

That pretty much says it iain... where have you been?..  8).....  ;D

[thurlow]

Jumping in kinda late here;  some of the old Gleaner combines (M, L, maybe the earlier of the II series) used 2 alternators;  my recollection is they were the Delco with internal regulators; 10 si;  don't know how they were wired, but it was a 12 V negative ground system.........

[iain]

I been on oliday with ALL of Linda's family sounds >:( :

but was  :D ;D 8)


iain  (pics to follow when resized)

[RichlandSawyer]

I sure hope you enjoyed your holiday while we were all sitting here struggling with this head scratcher. Its about time you show up!!!  :D  :D

And were is the woodmizer guys, isnt sparky the WM expert. Well now that the battle is winding down i guess i better go get working on the mill.