converting sawmill to electric?

[Den-Den]

Electric motor speed is fixed by the frequency of the power coming in to the motor. 

I agree that a 5 hp motor is adequate for cutting 14" diameter logs.

[muggs]

Oh a 5 hp motor will do it, just very slowly.

[Al_Smith]

Electric motor speed is fixed by the frequency of the power coming in to the motor.  

I agree that a 5 hp motor is adequate for cutting 14" diameter logs.

Then you are talking about a VFD  which would cost more than the motor .Plus you about need a "servo duty " motor else all the smoke will leak  out and it will never run again .

[bandmiller2]

This subject is almost as hot as the chainsaw oil mix fracas. Believe old Al he knows his stuff, its rumored he invented electric motors. I have a 15 hp Baldor three phase on my homebuilt band mill it has scads of power and never gets more than warm to the touch. It drives the mill and hydraulic pump. Its probably cheaper to build a rotary converter and go three phase. Google it there is much info on building one. A 10 hp single phase motor will turn the trick especially if parasitic loads like sawdust blowers and hydraulic pumps are run with different motors. Have a clutch so you can start no load be it a rocking motor or belt idler. I have run my shop for 40 years with a three phase rotary it works well and is old technology. Frank C.

[Al_Smith]

 :D I didn't invent electric motors .However my great grandfather worked for Thomas Edison .Matter of fact old grandpappy actually invented the rotary concrete kiln that burned powdered coal although old Tom took credit for it .In my garage I have a chest of machinists tools and in that chest are some of the tools grand pa Fred brought with him 120 years ago this month  when he took the boat ride over from England plus my dads journeyman card .I'm the fourth generation to own those tools .

[teakwood]

I researched a little bit.

Would this VFD work with a 5hp 3phase motor? 
https://www.amazon.com/HY-HUANYANG-Variable-Frequency-Converter/dp/B07HDYX25C/ref=sr_1_2?keywords=vfd+for+single+phase+motor+5hp&qid=1582374697&sr=8-2

of course i could go a little bit bigger, like 7.5hp, but i'm asking for the principals. would i need something else? 200$ isn't to much IMO


i can not find VFDs with single phase output, is there such a thing?

[Old Greenhorn]

:D I didn't invent electric motors .However my great grandfather worked for Thomas Edison .Matter of fact old grandpappy actually invented the rotary concrete kiln that burned powdered coal although old Tom took credit for it .In my garage I have a chest of machinists tools and in that chest are some of the tools grand pa Fred brought with him 120 years ago this month  when he took the boat ride over from England plus my dads journeyman card .I'm the fourth generation to own those tools .

Old Tom took credit for everything his men produced. They worked 12 or more hours a day, 6 days a week. I am not a big fan of how they teach about him in the school systems which translates into general public knowledge over time. Tesla was somewhat 'different' and a pretty darn smart guy.  ;D I know feathers get ruffled when I mention what my opinion of Mr. Edison is, so I will leave it at that and go no further.
My own Grandfather did some side work for Tesla when he was building his Shoreham experiment (I forget the name). Grandpop had met him when they were on lunch breaks in NYC, his lab was around the corner from my Grandfather's job as a steam engineer and dynamo operator supplying power to those big tall buildings in the city.
But I digress, now back to phase converters (and thank you Mr. Tesla for the wonders of AC).

[Al_Smith]

Rather than revisit little known  history ,which is interesting I'll just move along .
Now a funny thing I never understood is the misunderstanding  of electrical power usage and the costs involved .For reason unknown to me some people think they can use internal combustion engines more economically than electrical power .Nothing could be further from the truth except perhaps insisting the world is flat or the moon is made of green cheese .
If it were true modern manufacturing would still operate with line shafts driven by steam engines or perhaps diesels .Well it's not the case .

[Al_Smith]

Okay ,rotary converters work and work well .Then comes the conversation of erroneously labeled "solid state" converters .
In effect all they are is a starting circuit exactly like used on a rotary converter and only produce 58 percent of the usable power of a true three phase .
The draw back of this type option is the starting torque is much lower than true three phase and they should not be started frequently because of over heating .About no more than 3-4 times an hour or so .
Now I have hooked them up,trouble shot  them and they do work but I don't recommend them .If you're going to go with a converter either buy a good one or build a good one and be done with it once and for all . 

[Al_Smith]

On the VFD thing to be quite honest I've never worked on a small unit as they have all been large and rather high priced items used in the automotive industry .Obviously all three phase units ,480 volt input .If I'm not mistaken they were used in conjunction with 25 HP motors .Those were about 25 grand a pop .
On a band mill I'd think it would simple enough just to size the drive belt sizes to set  the speed .On the horizontal metal saws ,like "do-all "we had at work the band speed could be changed by shifting the drive belt from one size multiple pulley to another . Fact I've got an old Walker -Turner drill press circa 1936 that uses the same thing .That thing,old as it is with a 3 HP motor in place of an original probably 1/2 HP will break a 1/2" drill bit  like a match stick if it gets away from you .It's got a vise and I use it . 

[Woodpecker52]

My experience with an electric AC motor was using it to stop, start, reverse a gear box for lt15 bandmill which I automated.  I ran into it shutting down by heat switches after about 30 cycles.  I found a DC motor with AC converter and switched over.  I however realized after that I really didn't need to reverse the head as I just need to catch a ride forward, disengage and pull back by hand or ride, stop then pull back, it was faster pulling back than waiting for the same speed back.  The lt15 has a perfect place through the lower arm which a chain can run.  I just rigged a bicycle gear to catch the ride on, then stop and lift it by a handle and rod to pull head back.  With the DC it is easier to control speed.  I think it is a Dayton with the built on converter. Mill is stationary with pole power to it.

[moodnacreek]

Rather than revisit little known  history ,which is interesting I'll just move along .
Now a funny thing I never understood is the misunderstanding  of electrical power usage and the costs involved .For reason unknown to me some people think they can use internal combustion engines more economically than electrical power .Nothing could be further from the truth except perhaps insisting the world is flat or the moon is made of green cheese .
If it were true modern manufacturing would still operate with line shafts driven by steam engines or perhaps diesels .Well it's not the case .

Do I understand what you are saying here? Running a sawmill with an engine is cheaper than electric.The only reason I went to electric was for the convenience. I was running 3 engines and that got old. Buying power was way to expensive so I put in a 175 kw diesel to start a 75hp, 25hp, 5hp and room for more. Sawing belted to a diesel is more efficient.

[muggs]

Moodnacreek, I agree with Al, electric should be much cheaper than an IC engine. But you are running your own generator. That is a whole different animal. I am assuming Al is talking about buying power from the power Co.

[Al_Smith]

Try as you might you cannot make electrical power as cheaply as you can purchase it .The Amish that have the elders permission can generate it but it's a money loosing deal .Further more you can't dump fuel in an engine,gas or diesel and get the same cost saving .Now if you lived in the bush in Idaho or something in the middle of no where you might not have a choice .Most of us do .Unless you are a a "prepper " like Eustace on the history channel just to prove you can .It isn't my cup of tea but as I say what ever floats your boat .
  

[Al_Smith]

Now a story hard as it might be to believe .I knew this old bird who was a union electrician ,same as myself who evidently didn't know much .He bought this huge drill press at an auction with a ten HP electric motor he had the bright or not so bright of an idea to drive shaft it from an 80 HP Oliver tractor because he didn't want to run his electric bill up .I just smiled ,he never would have figured it out .Ralph had 10 kids and four teeth,get the picture . :D  

[Al_Smith]

Now rambling on .I have 3 generators ,two small single phase and one multi voltage multi phase old army signal  corps unit  that looks like a small locomotive .
During an ice storm some years ago the power was off for 4 days and I had no choice but to hook up the 5,000 watt unit .It sucked down a little less the 5 gallon in 9 hours at $1.75 a gallon then .So lets call it 14 gallon in twenty four hours more or less .Do the math .Now then think about that 20 KVA unit I have with a 20 gallon tank . Look up Generac, and check the fuel consumption,gasoline ,propane or diesel .It ain't cheap .

Don't get me wrong I like my generators and use them for certain things I can't stretch a cord to but in terms of economy it just isn't there .

[moodnacreek]

Al, you and I are not on the same page. I did a lot of research before I put in a generator. In this location I would have to put in 2 poles and a r.o.w to the power co. Then the 3 transformers , service to mill and so on. Then you get 2 meters one for running like your house and one for starting and that is the killer. One guy did this and took it back out. A factory down the road loads capacitors on shut down for the next start. The quarries around here all run generators because it is cheaper for them . This is the way it is.    I like your posts and this is the first time I disagree.

[teakwood]

ok, we pay 1.1$/lt gasoline, so like 4$ per gallon and that is very expensive, but also the kw is around 0.25$ so that's not cheap either. 
I want to go to electric because it's cheaper, quieter, less vibration, no stinky exhaust fumes to breath in, less maintenance, no annoying starting procedure.

I have one big 7.5hp from the sander, a real beast, weights 70kg, 1750rpm (way too heavy)
the honda has 20hp (had when new) is 43kg, 2500-3500rpm 
from the planer a 5hp, 3600rpm, around 30kg

I think i will make a trial run with the 5hp electric motor to see how that compares to the honda in cut force and speed. i just hook the motor up directly, no slow start or changeable speed control. i can do that swap without having to spend more than elbow grease. if that works i make a proper installation with speed control and overheating sensors.

  

[Den-Den]

Variable speed would be a luxury for a band mill, not sure it would be worth the cost.  Overload protection for the motor is important, even more important for a trial with a possibly undersized motor.  If you overload the planer motor and burn it up, the cost of this project goes up quite a bit.
At least hook up an amp meter and watch it closely while trying out the 5hp motor.  This would help you decide if it will work and whether you should change the band speed.

[teakwood]

thanks for the info, in the trial i will not saw a full day, just some cuts, so i won't overload the motor.

the motor says 25Amp, 5hp, 220V single phase, 2 pole, heat 60C,  so the 25 amps is what the motor consumes under load? if i pass that when in the cut i will overheat and eventually burn the motor? how do i measure that? i have a electrical meter, the yellow ones which can measure, volt, amps, ohm, i just know the very basics. how do i measure amps?

Variable speed would be a luxury for a band mill ,  i want something to have two speeds, a idle where the engine turns but not engage the clutch which turns the band and a speed for cutting. is there such a gysmo that i can buy? just a on/off and 2 speeds

[teakwood]

Overload protection for the motor is important,

@Den-Den

there is a overload protection on the planer, i probably hook that up also

[moodnacreek]

I try not to comment on wood mizer style mills as I have no experience with them. Do you just run the saw or do you idle on the gig back? Is the clutch necessary? Could you use a variable pitch pully to change blade speed? And does anyone use a Honda [or other brand] gas engine on propane for indoor use?

[teakwood]

Do you just run the saw or do you idle on the gig back? Is the clutch necessary?

now with the gas engine of course i idle on the gig back and when i have to move the log manually. i already have the clutch. i just don't want the blade running as i'm in front of it moving the log and as the electric motor should not be turned on and off every 3min that would be a very good option to have a idle speed so the clutch does not engage

[Al_Smith]

In essence the conversation went from apples to oranges .Actually on a small bandsaw mill it really isn't a cost worry to operate thing because it's not a high production situation so weather to run a gasoline engine or electric motor really doesn't apply.

   More so it might be good advice if you don't have a  good  knowledge of electrical work,specifically motors it's probably a good idea not to go there . ;)

[btulloh]

Material handling and organization improvements probably pay bigger dividends than foolin' around with the motor/engine.  The other side of that is sometimes we just do what we want to do.  It's the nature of mill owners, I think.