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Nother Question for electronics-mechanics

Started by Fla._Deadheader, February 21, 2003, 04:46:07 PM

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Fla._Deadheader

I'm thinking of adding an automotive alternator to my mill for higher amp charging of the batteries. Is there a way to also get 120 volts AC at the same time?? This would make it useful, in case I need AC power in a remote location, for lights, grinder, drill motor, ??
All truth passes through three stages:
   First, it is ridiculed;
   Second, it is violently opposed; and
   Third, it is accepted as self-evident.

-- Arthur Schopenhauer (1788-1860)

Kevin


Tom

Harold,
You will be glad that you installed an automotive alternator with all the motors you are running but what you need for the AC is an inverter.  They are readily available for 25 to 100 dollars and you won't be limited to your sawmill that way.  You can plug it into the sawmill or a handy car or truck and get AC for a power tool or lights........or coffee pot. ;D :D

Fla._Deadheader

I used to sell inverters and solar panels and wind generators. Problem with them is, it takes 3 times the rating to start a motor. The surge rating is what makes a GOOD inverter. I know you can run brush motors off an alternator. I just don't know how to wire it ??
All truth passes through three stages:
   First, it is ridiculed;
   Second, it is violently opposed; and
   Third, it is accepted as self-evident.

-- Arthur Schopenhauer (1788-1860)

Don P

I know just enough to trip breakers and smoke motors. :o It takes a modified regulator from what I understand. I've got some stuff on it if you want, frequency is not 60 hz. But they go on to say that most motors spun at 4-5% faster than nameplate RPM puts out rated voltage at 60hz. IM me if you want and I'll scan this.


ADfields

Your best bet is to get a belt drive AC generator and power it from the frount of your Porsh motor.  

Like on this list. http://www.northerntool.com/webapp/wcs/stores/servlet/CategoryDisplay?categoryId=182379&storeId=6970&catalogId=4006970&langId=-1&PHOTOS=on

Way #2 is get a surplus alternator off a helecoptor and convert it to 115 V AC.   I dont know how it's done but with some looking on the net you could find out.   A car or even a big truck alternator makes AC that is converted to DC inside the housing but the AC it makes is not 115V (I think it's 12 V AC) and would need ramped up to 115 and thats much like running an inverter.

I have a 1200 wat inverter and the surge rateing on it is 2500 wats but for what it takes to get one of that size you can get an AC belt driven generator.   I have 6 or 8 tapered shaft generators with cooked Brigs type motors sitting around that you could just have but you would need to cut a tapered shaft and a input bearing to make it belt deiveable.   When I kill a motor on one it's cheeper to buy a compleet generator than replace the motor so thay get added to the junk pile.   You should have them all over Florida for the halling off to.
Andy

Jason_WI

Fla._

Why not just carry a portable 4 or 5kW generator with you? That way you can use it for other uses than just by the mill.

A 3kW inverter should run a good size grinder with lights. Poor wiring is usually the reason inverters are unable to start a load. For a monster inverter you should use high strand welding cable(the size of your thumb) to supply the current from the battery. Keep the lines as short as possible. A deep cycle marine battery should be used as it has lower ESR(equalivent series resistance) and will be able to supply the current required without much of a drop in voltage.

Harbor freight sells generator heads that you could mount on your mill and use the mill engine to turn it. The more stuff you add to your mill the more that can go wrong.

 I have also seen generator kits that mount under the hood of a truck. Those cost more $$$ though.

Modifying an auto alternator will cause you more headaches than what there worth. One mistake and you will see lots of smoke :o

Jason
Norwood LM2000, 20HP Honda, 3 bed extentions. Norwood Edgemate edger. Gehl 4835SXT

carhartted

It basically comes down to spinning the generator at a constant rate of speed in order to get a steady 60Hz.  Most electric goodies don't like to run very well on anything but a good 60Hz load.  

My choice would be a seperate generator.

And just a reminder that the energy to run the generator has to come from somewhere.  I don't know what kind of power plant you have on your mill but can you spare five Hp to generate electricty.

Here's to making sawdust.

Fla._Deadheader

DanG Kevin, you throw links up like you have a library of 'em?? Spend all yer spare time on research or have ya got that "magic" puter touch?? Your links are always right on, Thanks.
  Youse udder guys. I already have a portable DC welder with modified AC power. It weighs about 250 pounds. If I keep gettin seperate toys, er, tools, I will need a MUCH bigger truck !! ;D
  I'm just recallin info from WAY back, in the old days, where you could hook this little box to yer auto alternator and run yer skil saw and drill and other brush type motors. Thanks for all the input. I will scrutinize it all and see what I come up with.
Carharted, I have al least 40 HP, probably more. That's one problem I Don'T have is needin HP. :D
All truth passes through three stages:
   First, it is ridiculed;
   Second, it is violently opposed; and
   Third, it is accepted as self-evident.

-- Arthur Schopenhauer (1788-1860)

Don P

The boxes you're talking about hooked up before the voltage regulator.Before the time of internal regulators. An alternator before the diodes and regulator produces three phase power, the voltage is dependent on the speed. the diodes rectify it to DC and the regulator limits it to 14 volts. So those boxes were just a switch and plug. If there is a voltage guage you can set the rpm to 120 volts. I think they were still using the diodes so you had DC 120 volts. Thats why the universal motors worked, or a coffeepot ;D. If you go before the diodes the frequency is in the hundreds of cycles instead of 60 cycles. They are doing 3 phase, high frequency to to try to produce ripple free, smooth, dc power. Most of the military surplus I've seen is high frequency stuff too.

D._Frederick

FLA_,
When I built up my mill, I went all electric ac, I figured that if I needed to go portable, I could get a PTO alternator and run it off of a farm tractor. In your case, the options would depend on how much you want to spent and how good your surplus supplys are. They make constant velocity drives that you can get on diesel engines for aux power and military use, I don't know how big or how they would mount, but they would give you a constant rpm for an alternator. You can get a 4 or 5 kw alternator run with a briggs,  but most of them run at 3600 rpm and will last about 500hrs of usage. If you plan on doing a lot of sawing off of the grid, put yourself a 25hp 3phase motor on the mill and get yourself a diesel motorgen set. A diesel will run all day at an idle on a couple gallons , and you would have power to run everything at your finger tips. The battery powered inverter would be my last choice, the guys that have them in there motor homes , say they are a pain in the butt.

solidwoods

You could use DC lights, and DC tools (welders use them) DC is tougher to lug around Amps, but its more user friendly.
Ret. US Army
Kasco II B Band mill
Woodworking since 83
I mill & kiln dry lumber, build custom furniture, artworks, flooring, etc.
If you mill, you'll be interested in some of my work in one way or another.
We ship from our showroom.
N. Central TN.

OneWithWood

Fla_Dh,
I used to have one of those inverter boxes on my truck.  After I replaced the wiring harness and the alternator the third time I ripped it out ??? ???
One With Wood
LT40HDG25, Woodmizer DH4000 Kiln

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