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converting sawmill to electric?

Started by teakwood, February 19, 2020, 06:32:34 PM

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teakwood

Hi guys, i have a champion sawmill, it's small and manual. like a woodmizer lt15 maybe. it has a 600cc honda twin engine with 20hp.

can i convert the mill to electric? i'm stationary in the shop, just single phase available. what motor would i need? whats the ratio for the band speed? electric engines turn faster than gasonline.

National Stihl Timbersports Champion Costa Rica 2018

Den-Den

A 10 hp electric motor would be a little under powered compared to your 20 hp gas engine.  15 Hp electric would be a little stronger than what you have now.
A single phase motor this size will be expensive and require a heavier service than typical for a house, you could have trouble starting the motor.  Even if starting is not a problem for the power supply, you don't want to be starting it very often because there is a lot of heat generated in a motor during starting.
Electric motors are available 1800 rpm or 3600 rpm (those are nominal numbers, will be a little slower when fully loaded). 3600 rpm motors are usually less expensive if other things are equal.
If you can work out the details, it will be less noisy and less maintenance.
You may think that you can or may think you can't; either way, you are right.

moodnacreek

In many areas 3 phase power off the pole is either too expensive or not available. Also the highly recommended 480V is not there but 208 may be. You have to call the power co.  A 3phase gen set is the normal way to go. A little much for one little sawmill but if you have or are adding more machines it is the way to go.

esteadle

Around here, they'll run 3-phase up to 400 feet from any existing 3 phase tranny.

In case that's not an option, here's a 16 HP 1phase 220v motor that will cost you 2 arms and a leg: 
http://www.electricmotorwholesale.com/BALDOR-GDL1615T/

Sell a foot and get the start controller: 
http://www.electricmotorwholesale.com/STECX95/

Al_Smith

This is a subject that has 10 thousand opinions and everybody claims to be correct .First it's an electric motor not an electric engine .There is a method which is very simple to use a three phase motor as a rotary phase converter to effectively generate 3 phase from single phase .Used three phase motors usually are very inexpensive,single phase are like the national dept .
A properly built converter works on about 92 percent efficiency .It's only job is to generate the third phase not perform any mechanical work .So as such it doesn't draw anything even close to full load power .
It's been said a 10 HP electric motor  should equate to about 20 HP gasoline but where that's stated I didn't bother to research .This I will say when I was a teenager a local hard wood mill replaced an Allis Chalmers   gasoline power unit which was right at 100 HP with a 50 HP three phase motor .It would always start,didn't require much maintenance and operated for pennies compared to that big gasoline engine .Lawdy that thing would blow your ear drums out ripping a big oak log .

moodnacreek

Quote from: Al_Smith on February 19, 2020, 08:15:45 PM
This is a subject that has 10 thousand opinions and everybody claims to be correct .First it's an electric motor not an electric engine .There is a method which is very simple to use a three phase motor as a rotary phase converter to effectively generate 3 phase from single phase .Used three phase motors usually are very inexpensive,single phase are like the national dept .
A properly built converter works on about 92 percent efficiency .It's only job is to generate the third phase not perform any mechanical work .So as such it doesn't draw anything even close to full load power .
It's been said a 10 HP electric motor  should equate to about 20 HP gasoline but where that's stated I didn't bother to research .This I will say when I was a teenager a local hard wood mill replaced an Allis Chalmers   gasoline power unit which was right at 100 HP with a 50 HP three phase motor .It would always start,didn't require much maintenance and operated for pennies compared to that big gasoline engine .Lawdy that thing would blow your ear drums out ripping a big oak log .
Yes, very true, been there and done that. A rotary phase converter can be used, but deals can be found on gen sets like never before and then you can do so much more.

pineywoods

One thing that will bite you converting to electric power..Big electric motors are HEAVY. On a bandmill, the head lift mechanics will have to be beefed up considerably. Bigger motor, heavier gearbox, which leads to beefed up electrical system, or you can go with counterweights..
1995 Wood Mizer LT 40, Liquid cooled kawasaki,homebuilt hydraulics. Homebuilt solar dry kiln.  Woodmaster 718 planner, Kubota M4700 with homemade forks and winch, stihl  028, 029, Ms390
100k bd ft club.Charter member of The Grumpy old Men

RichTired

Wood-Mizer has a 10 HP single phase motor or a 10 HP 3 phase motor as an option for their LT15 sawmill.  So based on that fact, you should be able to use a 10 HP electric motor on your sawmill.
Wood-Mizer LT15GO, Kubota L2800, Husqvarna 268 & Stihl 241 C-M chainsaws, Logrite cant hook, Ford F-150 Fx4

Richard

Al_Smith

I'm not going to argue with them but I do know how electric motors work in relationship to internal combustion engines .If not so modern factories would still be using line shafts like  in the 1890's .They don't by the way.. :D

Kindlinmaker

I have a 10 hp single phase electric LT15. Wouldn't change it out for any internal combustion engine. I cut 27" cants without any major issues. I may go a bit slower on the wide wood but I am not running for production so it doesn't bother me in the least. Keep in mind that electric is a whole different torque story than internal combustion. Starts every time, no maintenance, no down time and much less noise. I have more engines on trucks, tractors, splitters,and bunches of other equipment than I want to deal with. I will always jump at any chance to move to trouble free electric if practical. 

I am at a point where my body screams for hydraulics but I do not want to move away from electric. I am looking at components and shopping for a welder and hydraulic mechanic to help me build out an electric mill chassis. 
If you think the boards are twisted, wait until you meet the sawyer!

wiam

Started with an 18 hp Briggs on my homemade. When that blew up I put an old 7.5 horse Wagner on it. I slowed the blade a little and it worked ok. That motor stopped working and I threw a more modern 5 hp on it. A little slower but I don't push it too hard and it works for me. In my opinion don't get hung up on blade speed and a smaller electric motor will work. 

nativewolf

Quote from: Kindlinmaker on February 20, 2020, 12:20:13 AM
I have a 10 hp single phase electric LT15. Wouldn't change it out for any internal combustion engine. I cut 27" cants without any major issues. I may go a bit slower on the wide wood but I am not running for production so it doesn't bother me in the least. Keep in mind that electric is a whole different torque story than internal combustion. Starts every time, no maintenance, no down time and much less noise. I have more engines on trucks, tractors, splitters,and bunches of other equipment than I want to deal with. I will always jump at any chance to move to trouble free electric if practical.

I am at a point where my body screams for hydraulics but I do not want to move away from electric. I am looking at components and shopping for a welder and hydraulic mechanic to help me build out an electric mill chassis.
I agree, can't wait for the tesla cybertruck to get here so I can get rid of one infernal engine.  
Liking Walnut

teakwood

Quote from: Kindlinmaker on February 20, 2020, 12:20:13 AM
I have a 10 hp single phase electric LT15. Wouldn't change it out for any internal combustion engine. I cut 27" cants without any major issues. I may go a bit slower on the wide wood but I am not running for production so it doesn't bother me in the least. Keep in mind that electric is a whole different torque story than internal combustion. Starts every time, no maintenance, no down time and much less noise. I have more engines on trucks, tractors, splitters,and bunches of other equipment than I want to deal with. I will always jump at any chance to move to trouble free electric if practical.

I am at a point where my body screams for hydraulics but I do not want to move away from electric. I am looking at components and shopping for a welder and hydraulic mechanic to help me build out an electric mill chassis.
Thanks for all the good info guys.
I don't saw really big wood, just teak to max. 18" diam. i don't care if its not full speed production. i think a 7.5-10hp single phase would be the way to go.  
i could use the old clutch the gasoline engine uses so the starting torque of band movement gets softened.
some concerns for the electrics because i'm not that good with them. the electric motor will stop and start alot, every cut, is that a problem? will it over heat? will it draw too much electricity?  is a 7.5hp motor heavier than a 600cc twin cylinder gas engine?
National Stihl Timbersports Champion Costa Rica 2018

moodnacreek


An electric motor in single phase larger than 5 hp pulls a lot of amps to start. And if it was to start and stop for each board, the electric service would need to be larger than what most people have. Does Woodmizer use a clutch on their electric model?

Al_Smith

If it were 1930 perhaps the electrical services would be too small .However I seriously doubt that would be the case now .Not all but most would have 200 amp services which is plenty large enough to start a 5 hp single phase .

Here's an example : In my shop I have a 5 HP converter which provides both 240 and 480 volt 3 phase  power .This includes a 3 HP lathe,3 HP drill press and 1/2 HP Bridgeport milling machine .I can start all of them at the same time from a 40 amp circuit .The shop does have a 200 amp service . I also have a 5 HP large drill press with a single phase motor,converted line shaft machine ,circa 1910-20 .That  motor draws more than the three phase stuff and it's on  a 50 amp breaker .-----more next 

Al_Smith

Now then let me explain things knowing full well many won't be able to follow what I'm about to get into .When I build a converter  I go to extremes and use much larger starting capacitors than are necessary .My 5 HP unit has a 1500 micro farad starting  cap .That is how it can start a combined HP of 11.5 at the same time .Actually to be honest it was only by accident I found out it would because I usually fire up the rotary first  then the individual machines .
      Let me further say I'm only expressing options as I see them .However keep in mind I spent 4 years in the US navy submarine service as a tech .followed  by another 46 years as an industrial electrician .I retired almost a year and half ago having been in the work force until I was over 70 years old .
So what I'm saying isn't something I found on You Tube ,I've lived it and have done it . ;)

muggs

It is not a good plan to start and stop single phase motors often. Single phase motors use electrolytic capacitors for starting, they are only good for so many starts an hour. Each start produces heat. Also remember when a motor starts, it pulls 4 to 8 times the running amperage. (heat)So figure out a way to let that puppy continue running. Your caps will thank you.     Muggs

moodnacreek

Thanks for saying that Muggs. For years I ran a 5hp compressor off a 50 amp breaker. Went through a few motors. I think every light for miles around was blinking in time with the pistons. If you get on 3 phase all this calms down but you do what you have to do.

Al_Smith

Most compressors have unloader valves that are open on the start  up .If they fail it puts undue loading on the single phase motor start up which will eventually burn out the start windings .With a three phase motor you don't have that problem ,no start winding on a normal installation .

Now certain things like Y start/delta run,part winding start etc are only used in certain applications and certainly not on a small band sawmill .

I would say if for example people using a  Woodmizer with a three phase motor had  experienced any problem with them  Woodmizer would have addressed that problem a long time ago . Three phase IMO is far better than single if you can buy it or for that make your own with a  rotary .

muggs

Yea compressors are particularly hard on single phase motors because of the automatic switch constantly starting and stopping. If you burn out the caps, You should consider replacing them with higher voltage caps. they can take more abuse. That being said, my compressor has been working for over 40 years, no problems.  

Al_Smith

I've got a compressor I threw together from parts ,two stage set at 150 PSI high end dumping into two 60 gallon tanks .It's 5 HP single using a timer and a solenoid for an unloader valve .With 120 gallon  of air it will raise  my car lift about 3 or 4 times before it restarts .I think I have the restart at 125 PSI .The inground lift is a 13.5 inch cylinder and will lift a pick up truck on about 60 PSI . 

Usually if I'm not using the lift and just air tools I valve off the second tank .150 PSI will really turn an impact wrench into a power house .My home compressor  is only set at 100 PSI and is not nearly as effective .If I use it for something like spray painting I tee in another tank to keep it from short cycling and thus over heating .In over 35 years so far I haven't burned it up .  

muggs

Yea a bigger air storage is another good idea, to keep it from cycling so often.

Kindlinmaker

Quote from: teakwood on February 20, 2020, 07:33:25 AM

Thanks for all the good info guys.
I don't saw really big wood, just teak to max. 18" diam. i don't care if its not full speed production. i think a 7.5-10hp single phase would be the way to go.  
i could use the old clutch the gasoline engine uses so the starting torque of band movement gets softened.
some concerns for the electrics because i'm not that good with them. the electric motor will stop and start alot, every cut, is that a problem? will it over heat? will it draw too much electricity?  is a 7.5hp motor heavier than a 600cc twin cylinder gas engine?
The LT15 electric has a clutch just like an engined mill. I probably don't use it enough and overuse the switch. I'll be rethinking that a bit based on some of the great information being shared here. 

I am no electronics wizard so I don't pretend to understand all of the electronics in the fairly substantial control box attached to the mill but there are a fair amount of components inside.  I can tell you that I run the saw off a 50 amp circuit in my house panel with about 60' of heavy stranded line. If I remember correctly, it is about 40' of 6 ga. to a fused switch box by the mill and 20' of 8 ga. running to the motor. The house has 200 amp service.  The lights may dim a split second when I turn the saw on but all normal house activities are uninterrupted when the saw is in use.  I have several 5 hp and 7.5 hp machines in my basement woodshop which seem to have a similar or greater impact to the overall house on start-up. The LT15 might have a soft start built into the system; I checked the amp draw with a clamp on tester when we first assembled the mill and it only spiked to about 46 amps on star-up; dropped back to around 40 when sawing. It might might have more spike for an instant that didn't register on the meter but we have never tripped the 50 amp house breaker nor the slow burn fuses in the switch box by the mill.

If you think the boards are twisted, wait until you meet the sawyer!

Al_Smith

The compressor on my 5 HP geo-thermal will dim the lights .It's on a 40 amp breaker .Fact I've got a 4 HP direct drive 12" table saw that will also dim the lights a tad bit but the incandescent bulbs are nearly all changed to LED's so I don't see it as often as I used to .That's all single phase stuff 

My shop which is not where my home is has 15 8 foot high out put florescent and three low pressure sodium 400  watt fixtures and they won't fade on a start up .What few single phase stuff I have doesn't affect any thing and the three phase stuff fires right up running on a rotary .I have not had one problem with it .Fact as I type and when I get the time I'm throwing together a 10 HP air compressor on a 120 gallon tank .That one is large enough I could sand blast with it .That will take a larger converter but not to worry I have a 15 HP motor that will do nicely for that . I've also got a nice three phase transformer to jack it up to 480 volts . Not to mention I have an American "hole wizard " radial drill press that is all straight 480 volts that will require a larger converter than the 5 HP I'm running on now .     

teakwood

all good info thanks.

how can i regulate the rpms on a electric motor. is there like an idle where the engine turns but my clutch would disengage the blade and when i rev up it will start the blade and be ready to cut. how are the rpms for that, idle? and full rpm? 

what idle does a 2 cycle engine has? idle and full throttle? how do they compare to a electric engine.
 i have a 5hp planer and a 5hp sander both single phase which i could easily remove to make a trial run before i get into spending $  

I really don't see a reason where my planer motor which removes more than 5mm on a 6" board per pass should not be able to saw a 1mm kerf thru a 12-14" wide log 
National Stihl Timbersports Champion Costa Rica 2018

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