100 hp 3 phase

[Magnum660]

Hi everyone, I have been reading lots of good threads the last few weeks on the forum and decided to finally sign up. I hope to be a regular and gain insight on all aspects of the forestry industry!  I am ready to buy my mill. It is a old corley circular running a 60" blade driving by a 471 detroit. I really want to find a 3 phase motor to run the mill. My question is how do you know what motor to buy to make the mill run correctly, and if anyone knew were to find good used ones. Thanks

[bandmiller2]

Mag660,alot depends if you have three phase power and if so how heavy your service is.I would think you could get by with a 50/60 hp three phase motor,especially if you drive auxiliaries from separate motors.Companys that service commercial pumps and circulators will often replace units when the only problem is the pump not the motor and they can be had for scrap price. Frank C.

[Magnum660]

Thanks bandmiller2.  Do you know if I would have to rig up some kind of reduction to make the blade turn between 400 and 600 rpm with the motor?

[Meadows Miller]

Gday

And Welcome to The Forum Magnum660 Nice to have another bloke aboard who is not scared of a Real Mill  ;)  ;D ;D ;D 8)

The Corleys are a good sawmill like most of the ones still building crcular mills you can still buy new parts  ;)

I prefer 100hp myself and that is what the ole Meadows is getting and thats what it had back in the day was 100hp on the headrig 75hphp on the edger and 15 on the blower and two 10hp hyd powerpacks  ;) Now the Laimet I have runns 150hp on the saw and is setup with two motors in tandem 70hp and 80hp one starts it moving and the other kicks in when its upto speed that also reduces the Start Load  ;) All the laimets and Karas I have run thus far where all in the 70-80hp bracket for the same size mill so Im thinkin 150s alittle overkill but im not complianing atm either but I still might drop one of the saw motors on the laimet yet though  ;)

You gear electric mills with the pulleys so you need to know you saw speed aand what you motor speeds are before you do the calculation avoid huge rpm electric motors also something in the 1200 to 2000rpm range is the motor your looking for Mate ;)

Regards Chris

[jdonovan]

" blade driving by a 471 detroit. I really want to find a 3 phase motor to run the mill. My question is how do you know what motor to buy to make the mill run correctly, and if anyone knew were to find good used ones. Thanks

The 471 was about 150 HP when new. I seem to recall the suggestion was at least 2:1 diesel to electric when doing a replacement, some will sat 3:1.

So at a minimum you'd be looking for 50HP, perhaps 75HP.

That is a BIG electric motor, and will take a very large industrial 3-phase service to run.

Most large electric motors are going to be 1800 RPM, depending on what the old engines speed was, so you may need some speed change plans.

If you don't already have a very large 3-phase service at, or adjacent to your site, re-powering with a new diesel will probably be cheaper.

[bandmiller2]

Chris,of course,is right the more HP you have on a circular mill the better.My main concern is the capacity of your service,100 HP and over your running with the big boys.If you have the heavy three phase go for it.If your mill will be used part time you would probibly be better off with the Detroit or a large tractor PTO. Frank C.

[dblair]

welcome to the forum , I was looking for a big electric many years ago and found lots of them at a metal recycling center . all were reasonable in cost , good luck on your project .

[Magnum660]

Thanks for all the great insight.  I had the power company out today to discuss the 3 phase service.  I think that his thoughts were the same as bandmiller's (a mill that is used partime, like i will, would be smarter not to invest in the 3 phase service). One reason I want the 3 phase is for my support equipment. I found a sweet buy on a morgan triple trim saw that is three phase, and a morgan single resaw that is gas powered 20hp honda. What are your thoughts on replacing these motors with single phase electrics? Thanks again.

[hackberry jake]

It amazed me when I worked for a commercial hardwood mill around my neck of the woods that the three phase power came in on wires the size of a pensil until it got to the transformer. This mill ran a 300hp headsaw with ?? Hp tripple vertical edgers and a seperate brewco run-around resaw running a 2" band with a dedicated edger and a 80' long green chain. The power company can put a hole lotta power in little bitty wires as long as the volts are high and the amps low. We would be a lot more efficent country if we did like europe and did away with 120 volt power.

[francismilker]

It amazed me when I worked for a commercial hardwood mill around my neck of the woods that the three phase power came in on wires the size of a pensil until it got to the transformer. This mill ran a 300hp headsaw with ?? Hp tripple vertical edgers and a seperate brewco run-around resaw running a 2" band with a dedicated edger and a 80' long green chain. The power company can put a hole lotta power in little bitty wires as long as the volts are high and the amps low. We would be a lot more efficent country if we did like europe and did away with 120 volt power.

Used to amaze me too until I did a 10 year stint as an electrical lineman.  After I got to know ohm's law and realized they could do it because they were supplying 7200 volts and very little (around 5) primary amps.  Once it got to the stepdown transformer, like you mentioned, the volts went down and the amps went up. 

Magnum660, a 100hp motor on a 3-phase service is going to be pretty costly to get running if you don't already have the service there.  You're looking at a transformer bank of 3-37.5kva transformers unless you want to use a "poor boy" bank and then they'll install a couple 50kva pots and run you some delta 3-phase.  When you get over 25kva whether it's single phase or three phase, they usually charge you a "demand" fee for service built in to you whether you use it or not.  That's all not to mention what size conductors your going to have to run depending on what voltage and distance it is from the service. 

As far as your questions about motor speed, remember the plate on the side of the motor will give you rpm's but that's referring to shaft rpm's for direct coupling drives.  If you want to change the output rpm's you'll need to pulley it down or up. 

Good luck on getting up and running. 8)

[bandmiller2]

Mag660,I'd run your mill with the detroit or a tractor and make/buy a single to three phase converter for your support equipment.Depending on the motor size on your edger it may pay to just put a single phase motor on it.

[Al_Smith]

On those gasoline powered aux equipment you could probabley half the HP going to electric .Easy enough to run from a rotary converter .

Now a 100 HP motor is a horse of a different color because it's unlikely you'll find one that is wired 240 volts so it's going to be 480 .You  have to motor to deal with ,a seperate step down transformer to get a usable voltage for lighting etc plus the motor controls to run the big motor .

That big motor will draw 125 amps running full load and could be 3-4 times that starting it unless you wired it reduced voltage start which is another expense .

[thecfarm]

Magnum660,welcome to the forum. What's all the lumber going to be used for?

[Magnum660]

I run a logging operation in the winter and summer months, we have a custom manure hauling and spray service we do in the fall and spring, I want the mill running to keep my seasonal help busy so they dont look for work elsewhere.  I plan on milling the trees for rr ties and pallet lumber right now.  Hopefully in time I can find some other ways the lumber can be used for.