Hello, I am new to this list and am not an electrical contracter or electrician. I have a sawmill and lumber business in the Missouri Ozarks. I have only single phase power with a 200 amp service at the end of a line. The area I am in is very rural with no electrical codes that I know of and no electrical inspections or inspectors. With my 200 amp single phase service I run a 40 hp on my sawmill, a 20 hp on my band resaw a 10 hp on my dust blower, Two 5hp and a 7.5hp on my molder, 5hp on my planer and a 5hp on my blower which pulls the shavings from around the molding and planing heads. All of these motors are 3 phase. To make the 3rd leg (manufactured leg) I use a 25hp 3 phase motor. I ran the 2 lines from the power company to my main disconnect and from there I used them as L1 and L2 when I wired them to my 25hp. For L3 I ran a wire from the 25 hp back into my main as if it were coming from the outside. From there I wired up all of my 3 phase motors as they would normally be wired. I use a small single phase motor to get the 25hp up to its running RPM. Once the 25hp is up to rpm I turn on the 25 hp motors disconnect. The 25hp will run at rpm from the 2 outside lines and while doing so will generate the 3rd leg. Now, The 40hp on my sawmill is to big to start by itself so I use a 10hp 3ph motor to get it up to rpm, then I shut down the 10hp, from that point I can start all of the rest of the motors on their own, even the 20hp on my resaw without dimming my neighbors lights. I do utilize several run capacitors. I had to set this system up this way for several reasons. #1 I cannot get 3 phase power out here. #2 I knew I could not use a regular rotophase as a friend of mine had tried to use one a couple of miles from here to start and run a 15hp motor on his band sawmill and it dimmed everyone's lights for a mile or two around every time he started the thing and so the power co op shut him down. That is the problem with bigger rotophases. Were ever you need them in rural areas you can't run them because they pull to much current when they and the motors that are connected to them start. Thus, I knew I needed a system with no start capacitors. What is neat is that this system works much better than I had thought that it would. For each motor I bring on line everything becomes more balanced and efficient (it costs approx $9.00 per day to run everything). The 40 hp on my sawmill has plenty of power does not bog down and does its job very well. What is really amazing is that my resaw has a computerized electronic controller that runs a small 3 phase motor that powers the variable belt feed. This device is supposed to be very sensitive. Yet I have never had a problem with it. In fact I have been running my operation with this set up for 5 years now and have had no problems at all, which is truly amazing since I bought several of the motors, disconnects and magnetic switches used. Now here is my dilemma. Back five years ago after I put this thing together the power company had qualms about hooking me up. In fact the engineer said that it would not work (not much of an engineer huh.) Anyway, I knew a guy in Arkansas that was running 3 times as much stuff as me with the same kind of set up at the end of a line on three 200 amp services. In fact he generated the 3rd leg for the entire thing through a 20hp delta Y motor ( I have to say though that when I leaned over to look at this motor a bead of sweet fell from my brow onto the motors case and it went psst and evaporated.) What is really wild is that once he brought several motors on line he could actually start a 50hp on this system without dimming his neighbors lights. He was very good friends with the guy who runs the electric coop down their. So, to make a long story short he had his electric co op guy talk to my electric co op guy and my electric co op guy reluctantly agreed to hook me up. The hook up was conditional though. The conditions were that I would be disconnected at the first sign of a problem and that I was to never ask for any more amps. Well I am at the point were I want to replace my existing saw mill with a scragg mill that runs from two 50 hp motors. I would also like to change out the 25 hp motor that I use to generate my 3rd leg with the 40hp that I have on my present saw mill. I believe there is a way to do this without getting another 200 amp service. I remember when I was a kid there was a sawmiller were I grew up who used an old 3 ph motor body to convert 220 3 ph to 460 3 phase. The thing, is I do not know how he had it wired up. I do remember that it was not running and he said it did not pull any juice. In fact I think the rotor had been removed. I can't be sure I was just a kid and the memory is fuzzy. Essentially I think he was using the stator as a transformer to convert the 220v to 460v so that he could run more horse power on less amps. If I could do what he did I could wire all of my motors 460 volt which would give me the ability to add the motors that I need to add and run them from my existing 200 amp service. I can not find any info on this anywhere on the internet or otherwise (I guess the guys who write the NEC haven't heard about it yet ;o). In fact I cannot find anything about the set up that I have and I have seen several half assed Mountain and farm boys use this kind of thing for different purposes. If any of you guys have seen this transformer thing maybe you could tell me how it is done. Or maybe someone knows of a device I could purchase to turn the 240v to 460v. It would save me the time of experimenting with a small 3ph motor until I do figure it out on my own. I apologize for this very looong post but I just wanted to put all the info in here so that you guys would know the whole background. Thank you for any help you might be able to give. I hope I have not made you guys cringe to much.
Hillbillysawmiller
