I built a band sawmill which works pretty well. I am now working on putting an electric motor on to move the mill head and I am wondering what speed the head should advance.
William
Hi Wiam. Did the same thing. I have access to small gear-reduction motors and rigged one up. It is a 3.5:1 ratio. Then I set up a pulley system with 1.5" on the motor, to 10" on the shaft-sprocket drive. I can turn it with a short crank handle. I got a DC motor controller from a guy on Ebay. It worked for 10 seconds and popped a capacitor. He is making changes to it and I will report on it as soon as I get it installed.
Your feed rate needs to be variable. You need to go slower when you approach a knot or burl and can then speed up when you have clear log. On the return, you want it to gig back as quick as possible to keep production up.
Wiam,
Like Fla_ said that you need to have a variable feed rate. If your mill is using 1 1/4 blade with less than 20 hp, your feed rate should be 0 to about 75 ft per min. I use a 1/4hp permanent magnet 60rpm gearmotor with an SCR control on my mill with good results. It provides about 80-90lbs of pulling force.
Hi D. We may have talked about this before, but, I can't find the info. Exactly what brand-type motor did you use and could you explain the "scr" drive and how to hook it up? In case I am not satisfied with my set-up, I would like the info on hand to make the changes. I can do most anything with electricity from low DC to high voltage AC. This "electronic" stuff baffles me though. Thanks, Harold
Fla._Deadheader
If you popped a cap then there is going to be more than just a few changes. Either overvoltage or the ESR(Equilavent Series Resistance) of the cap was too high and the ripple current caused it to vent(pop). This leads to design flaws from the start.
I see all kinds of home brew motor drive stuff on ebay and I always wonder about the quality and duribility of it.
Jason
Jason. The guy that made it said I had a Series wound motor and this PWM was not designed for it. I got him to make another board that the PWM will run 2 mosfets, that will in turn, run the motor. He also added 2 varistors to absorb the high voltage spikes that were what was causing the PWM to malfunction. We'll see tomorrow if he knows what he is doing. Everything is rated for 120 amps, so, it should work ??
Fla_,
I bought the gearmotor and control from WW Grainger. The SCR control I am using takes 120v-ac and converts it from 0 to 90 volts dc. Its easy to hook-up, you should have a switch to control the ac (on/off), the SCR control has two leads running to a Pot- to control the ouput, and two leads running to the motor, you should have a DPDT switch to change the rotation of the permanent magnet motor. I have used it since 1990 with no problem.
You can get 90volt dc grearmotor and the controls through surplus dealers. I have bought stuff from SURPLUS CENTER 1-800-488-3407, call for there catalog. They sell at about 30-60% of new. Let me know if you want more detail.
Thanks, D. I figgered that you were using AC. My mill will be portable, so, I need DC for all the motors, fed from a battery. Got any ideas, anyone ??
Forgot to add, we sawed this afternoon, for about 4 hours. Didn't hook up the PWM system. The guy that made it wants a simple 1n4001 diode put in the system. Think I could find one in this town??? NOOOOOO. I PO'd the guy that runs the Radio Shack. Told him this used to be an electronics store, NOW, it's a *DanG toy store.
Ennyhoo, sawed the other half of the Cypress stump and one of the larger Brown Cedar logs. Used a new Woodmizer blade, first. Don'T like them, at all. Not enough sawdust removed from the cut. Got hard to keep it from getting wavy. Tried to crank more tension in. Just put a lot of extra strain on everything. Took it off, right in the middle of a cut and put on a Timberwolf. Man, what a difference. Nice and smooth, LOTS of dust flying out the chute and let off a BUNCH of tension.
I'm sawing dirty logs and Don'T get a lot of bd/ft per blade, but, I'm just playing now, checking all the other things that could go wrong. The woodmizer blade pulled the Porsche pretty hard, while the Timberwolf walked right through the Cypress. Both blades are "supposed " to be 10 degree and .024 set, I THINK. I need to get them both on my home built dual tooth setter and check them out. ;)
Fla_.
Get the Catalog from the Surplus Center , they have a lot of 12 and 24 volt dc motors that are not series wound. WM uses a lot of 12v equip, find out the mfg and were you can by it. They also have electornic controls for the 24 v dc systems at th Center.
I also would check the set, also the wider the cut the more set required.
I would be interested in knowing how you feed works using a series would motor, it is hard to control the rpm of this type motor. (the rpm is based on the amount of load where as a compound motor will have a more constant rpm)
Hi D. Been shopping Surplus Center for years. Built my 4 KW Wind Generator from their parts. Worked like a charm. Had a 17 foot blade span. Took an indirect hit from a tornado and threw the blades. Sold the place soon after and the new owner never fixed it ?? We had NO light bill for 5 years. :o
I used one of their gearmotors for the clamp drive and another for the outboard saw guide adjuster. Both work well.
I have thought of putting an AC alternator on the engine, and running the SCR off of it. Didn't know if the varying frequency would mess up the SCR unit, as the engine changed RPM when in a wide cut. I still have to figger how to hook up the goverment for this engine. I got a belt drive one??
My poor head must be geared too slow for I am having a hard time following this. ::)
Florida_deadheader,
Try designing that speed control as a pulse width modulator driving multiple power MOSFETs and see if you get the proper speed from it, I could send you my old control from my WM, but I'll forewarn you that it overheats if you push it too hard and then open-circuits. I replaced it and the problem went away so I'm pretty sure I replaced the right part.
Fla_deadheader
If you really want 110VAC on your mill then just install a power inverter. It takes 12V DC and outputs 110 VAC at up to 3000 watts. You will need a beefy alternator to feed a hungry 3000 w inverter though.
Also if it rains,which I hear it does a few times a year in FL ;D, you will need to isolate and insulate all those goodies hooked up to 110VAC or some of those metal parts on your mill may become energiezd when wet :o
Jason
Energized wet parts ain't all that bad. When I used to do the lineman thing, When we worked in the rain, on a delta primary system, we would have this blue halo glow all over us. Some people driving down the road in the darkness of the night, would stop and talk to the ground hand, thinking that we were being electrocuted!! We told 'em that we were direct disciples and they would get REAL quiet !! :D :D :D
Min-boy. That is eggzackly the system that I bought off ebay. The guy says it will work fine?? ::) We'll see !!
I would really appreciate the borrow of yer mizer part. I will give ya a PM with a shipping address. Thanks a bunch, Harold
All alternators make AC power thats why thay call them alternators not generators. The ones on cars and sutch convert it to DC inside the cace. I have seen Delco truck alternators reworked to put ot 115VAC but the hard thing is to get a flat 60 cycles from it, it's rpm driven. Most non brush type AC moters WILL run just fine on 115VDC and thats not at all hard to get from that Delco truck alternator. You see 115VDC plugs on gas driven DC welders a lot and if you plug a aingle grinder with a brush moter in it! :o :o
I would think your on the right track with 12VDC Harold. Have you considered old wheelchair moters if the e-bay parts dont work out? Thats what I'm thinking on when I get that far, one side of the chair for feed the other for head up/down. Got that one from Junk Yard Wars when thay bilt jousting RC cars.
Andy
Andy, down here, everything classified as "junk" is gold plated. You sometimes pay as much for salvaged parts as you would new. I studied wheelchair parts, but, went with Surplus Center and the Ebay guy. That way, I got direct dealings and can get replacement parts or electronic advice quickly.
Harold
Do you have a part # from surplus center for the motor that you chose?
William
ADfields,
The only electric motors that will run on both dc and ac are universal type that are used on portable saws, drill, & etc. They have brushes. If they have a speed control, its good-by if used on dc.
Fla_,
Your idea of using an alternator off of your saw engine would cause problems when idleing, there would not be enough rpm change when sawing to cause a problem. Most of the SCR drives will operate 50 hertz. If you would keep your engine running at sawing rpm, you should not have a problem.
Thanks, D. You are a good source of info. NOW, where were ya when I was buildin this thing?? :D :D :D ;). I only slow the engine when I want to stop and check all the moving parts for failure, or, when we are loading or fetching a log. I Don't see the reason for idling or clutching, when giging back??
Wiam, which motor are you asking about?? I got 5 different ones doing 5 different functions??
Harold
I was referring to the motor you are trying to make your carraige move with. I use an ATS 2000 superwinch for my raise/ lower, which works well but I don't think one could be used with a speed control.
William
Wiam. I am using an outboard motor starter motor. It is gear reducted and is further reducted with belts and pulleys. I took the end off the motor at the gearbox, and added a second set of insulated brushes, so the + cable AND the - cable are both insulated from the case ground. That way, you can reverse the voltage flow without shorting out the battery leads. I have 2 outboard mechanics as friends and have access to lots of these motors, IF I need a replacement.
Harold
I need better friends. :D :D
William
On my Kasco, they use a DC Gear motor with a sprocket output to a chain. It is speed controlled by a rheostat. No other parts.
Gearmotor about $200
Rheostat about $30
Labor Priceless.
If any one wants "Make Model" just ask.
The gearmotor is very very good quality, and has an internal clutch that slips when your cutting resistance is more than the rheostat is set for.
This is so someone can stop the mill head by hand, or if the head hits something and stops its feed, the motor/wiring won't be damaged
JIM
Jim
ok tell me more about make/model and where to get.
William
Naturally, the 10yr old mfr label on my 2 gear motors are rotton off. I called Kasco to find out what make and mod the motor is. Steve said they get it from Stature Ele. Stature does a mod on them, but Steve did'nt know what the mod is (I know, but if someone dosent want to tell me, I don't pressure them).
Kasco price $456
I'm not a betting man, but I remember seeing the label over the years, and I'm sure it is a Dayton.
Dayton Grainger stock no. 11480 to 1175 each has rpm .
Grainger price oops 1995 price $91. The only prob is, the item description dosent say anything about an internal cluch. The ability of the mills feed sys to be stoped by hand and not dammage motor or elecs is important. I would call Dayton and ask a tech about this. Also I would design toward DC gearmotor (generally overall less amps than a large motor) Less amps mean rehostat instead of DC controller. Controllers cost a bit , the rehostat is $30 or less and I feel is a simpler more durable concept.
I use a Motor Reversing Switch $30ish for reversing the feed (reverse the wires on these DC perm mag motors and they run reverse)
If you want mo info, E-me with youre phone #, or E-me and I'll E-you my #
Jim