LT40 Gas to Electric?

[wetdog]

Has anyone ever changed their LT40 over from a gas engine with 12VDC controls over to electric motor and AC controls? If so, how did the modification go?

[Bibbyman]

Lots of folks have changed from engine to AC motor.  If you get a motor with same specs as installed on a Wood-Mizer for that model,  it's a fairly painless conversion.

I don't know anyone that has changed the controls from DV to AC.  Lots of problems, many may be insurmountable. 

[wetdog]

Lots of folks have changed from engine to AC motor.  If you get a motor with same specs as installed on a Wood-Mizer for that model,  it's a fairly painless conversion.

I don't know anyone that has changed the controls from DV to AC.  Lots of problems, many may be insurmountable.

Do they still use a battery with a charger for the DC voltage or some kind of converter?

[Dave Shepard]

AC mills typically have an alternator to charge the battery. I'm not sure about the LT70 AC that uses AC drive and up/down motors.

[Bibbyman]

Any I've seen use the same alternator as engine.   The AC mills are identical to engine models.  Just replace engine with motor. Replace fuel tank with box with starter switches.

http://www.youtube.com/watch?v=c2Jx3bekr1M&feature=youtube_gdata_player

About one minute into this video you can clearly see the alternator mounted beside the motor.   

DC controls,  good or bad, are already there and supported by diagrams and parts from Wood-Mizer. Rip them out and you're on your own.

[Kansas]

The LT 70 AC does not use a battery. Not an electrician, but I think trying to convert DC to AC would be a nightmare. Also bear in mind this. Woodmizer's electric motors are proprietary. I think I would consider just going with a standard 25 horse motor, and make your own mounting.

[Bibbyman]

The LT 70 AC does not use a battery. Not an electrician, but I think trying to convert DC to AC would be a nightmare. Also bear in mind this. Woodmizer's electric motors are proprietary. I think I would consider just going with a standard 25 horse motor, and make your own mounting.

While they say AC,  I bet a lot of the controls, small motors are DC. Probably have some kind of converter to power them.

[ElectricAl]

Wetdog,

Back in 1996 we converted our 1993 LT40HDG24 to an E15 using a conversion kit provided by Wood-Mizer.

The conversion went well other than we had to change the pulley diameter on the electric motor.
The Motor turned at 3450 rpm and the gas engine turned at 3600.
The WM kit was set up to use the gas engine pulley, thus the blade speed was about 5% too slow.

As stated earlier don't change the 12 volt up/down and Fwd/Rev motors. Just use the Alt that is on the machine.

If you want actual AC drive motors for up/down and Fwd/Rev plan on emptying you wallet for Frequency Drive Inverters.
You'll need an Inverter for each motor.


What year saw are you working with ?


ElectricAl

[wetdog]

ElectricAl,
I have one same as yours, '93 LT40HD24. I know a new engine will be in my future and I was thinking of going stationary anyway. Do you find the electric cheaper to run and less maintenance?
Wetdog

[ElectricAl]

Wetdog,



When we converted from Gas to Electric, gas was 99 cents.
Our fuel bill was $450 a month. After the conversion our power bill went up $50.

Our power rate has gone from .06 to .12 a Kilowatt over the years,
so we would be paying $100 now.
With gas, we'd be out of business, oh I mean $1575.

On top of the Fuel cost we changed Oil and Filter every 50 hours.

Plus the Gas engine bogged down while sawing. The Electric pulls a steady RPM.

Electric is also quieter and less stinky.

Now keep in mind there is some maintenance required with the Electric Motor.

Bibbyman is always ready to explain his extensive Electric Motor Maintenance Program.

# 1  Two pumps of grease once a year.
# 2   Remembering to do step # 1   


ElectricAl

[wetdog]

ElectricAl,
Does your mill still have the blade disconnect lever or is the blade live whenever the motor is turning?

[Dave Shepard]

I am in the process of reversing what you are doing. I'm putting a gas on a '92 LT40E15. The only thing that really changes is the engine. Rig up an alternator and away you go. The Wye-Delta soft start on the factory mill uses 12v DC. If you want to have keyed start off the panel, you will have to take that into consideration. If not, then put a starter on the fuel tray. What are you going to use for power? Do you have three-phase, genset or phase converter? What size motor are you going to use? That mill would have originally had a 15 HP with a 215T NEMA frame. You can buy all the parts, suck as mounting plate, special sheave, belts etc., right from Wood Mizer to mount that motor. The voltages are weird on the WM motor, but a standard 15HP with a 215T frame should bolt right on. I'm not sure if a 25HP would be the right motor for that mill. I believe member Faron has a 20HP electric on the same vintage mill.

[Al_Smith]

The conversion factor is normally taken as 1HP electric equals 2 gas or diesel .I know a zillion people will argue that fact but it's true .

The LT 70 shows 55 HP diesel while the electric is 25 .I rest my case . ;)

[Dave Shepard]

WM claims they can pull 70 HP out of that 25HP electric for short periods. :-\ Not sure what that's all about. I know the 15HP electric on the '92 was easily as powerful as the 24HP Onan on the identical '93 mill.

[bandmiller2]

I don't own a WM, my mill is of my own manufacture.Origanally I used a two cylinder Wisconsin baler engine aprox. 15/16 hp. it did the job but no spare power.Replaced it with a three phase baldor 15 hp motor plenty of power to turn the band and hydraulic pump.For me it was a direct replacement even used the same belts.Only thing I had to buy was a used motor starter.I retained the belt idler type clutch so the motor starts no load which reduces the startup load.As stated I wouldn't mess with the 12v controls but have a good sized battery and 120v charger hooked up.Much more economical to run than gas or diesel. Frank C.

[ElectricAl]

Wetdog,

Our 1993 used the same manual clutch and band brake system for the Gas or Electric.
The only change was the Power Plant. Mechanically everything else was the same.
We even used the key switch to start and stop the motor.

Al_Smith is right about the HP . There is a big difference between the Onan 24 and the Baldor 15.

Electric Motors don't bog down, they just pull more Amps until it stalls.

[Bibbyman]

A few words about motors. 

Just because the nameplate says a horsepower doesn't mean it's equal to the motor next to it with the same horsepower rating.   Motors are designed for specific applications.  A motor designed for a constant load, like turning a fan, will be designated different from one that starts and stops. One that starts under load, like for a concrete mixer,  will be designed different than one that starts under no load and then load is applied.  Wood-Mizer motors are designed to start under no load and then endure temporary heavy load.  That's why they can pull so much more horsepower than the nameplate says.

Then there is environmental considerations.  Some motors are designed to run in a clean, dry environment.  Others in an exposed to weather environment.  Then others are closed and built to work in a harsh environment.

If you go with a motor from Wood-Mizer or one from a Wood-Mizer mill, then you won't have to worry.  They have it figured out. 

I had a customer that had a PHD in industrial engineering look at the plate on our Super. His comment was that it was way over designed.

[wetdog]

I am in the process of reversing what you are doing. I'm putting a gas on a '92 LT40E15. The only thing that really changes is the engine. Rig up an alternator and away you go. The Wye-Delta soft start on the factory mill uses 12v DC. If you want to have keyed start off the panel, you will have to take that into consideration. If not, then put a starter on the fuel tray. What are you going to use for power? Do you have three-phase, genset or phase converter? What size motor are you going to use? That mill would have originally had a 15 HP with a 215T NEMA frame. You can buy all the parts, suck as mounting plate, special sheave, belts etc., right from Wood Mizer to mount that motor. The voltages are weird on the WM motor, but a standard 15HP with a 215T frame should bolt right on. I'm not sure if a 25HP would be the right motor for that mill. I believe member Faron has a 20HP electric on the same vintage mill.

I would most likely use a phase converter with the 15hp motor. What do you mean when you say the WM motor votages are weird, is in not a typical 240/480 three phase?

[Bibbyman]

Wood-Mizer motors are standard voltages.  If you have three phase service,  then you'll jest need a fused disconnect switch to protect it.

Many of us only have single phase service.  In that case, we normally use a rotary phase converter.   Single phase goes in, three phase comes out. 

Then there are variable frequency drives.  They convert single phase to three phase but do it in a solid state.  The variable frequency drive has some real advantages.

ElectricAl runs his new LT50HDE25 Super on a variable frequency drive.  He can tell us more.

[ElectricAl]

Oh ya, I can tell you more.

When you spend $40k on a new mill and it does not start because the Power Company does not have enough hamsters on the wheel you need to be creative.

For us the best option was a Variable Speed Frequency Drive.

In real simple terms it's a box of magic.

220 volt AC single phase is all it needs.

The Motor spools up in 7 seconds, and stops in 10 seconds.
Does not dim the lights or pith off the neighbors with brown outs.

Our Drive cost + - $8000  for the 25 hp motor.

A Drive for a 15 hp would cost less.

[bandmiller2]

Electric Al and cornfield Al,$8000 is a lot of quid.Would it work to have two identicle 7 1/2 hp single phase motors belted  to the band.??Start one then the outher to lower start load.Seems like it would be cheaper and simpler than the majic box.With a rotary three phase converter what would be the losses to get 15hp to the band.?? Thanks guys. Frank C.

[Dave Shepard]

By weird voltages I meant it was designed to run in other countries. It will run on US low and high voltage, but also on other voltages and hertz. Below is the nameplate from a factory '92 WoodMizer 15hp electric.



 

[ladylake]

I like Frank's idea of 2   7-1/2  or 10 hp single phase motors, the only downside would be weight which I'd guess less that a bigger diesel.   Steve

[Bibbyman]

I like Frank's idea of 2   7-1/2  or 10 hp single phase motors, the only downside would be weight which I'd guess less that a bigger diesel.   Steve

But his 93 LT40 wasn't designed for that much weight on the head assembly.   Also, I don't think single phase motors are as efficient as 3ph.

[ladylake]

I looked up the weight, a 10 hp single phase is 140#, so that would be 280 or a little less than a 3 cylinder diesel.  Also I'm not sure but don't 3 phase motors   only put out around 2/3 of there rated hp with a phase converter?

[Bibbyman]

I looked up the weight, a 10 hp single phase is 140#, so that would be 280 or a little less than a 3 cylinder diesel.  Also I'm not sure but don't 3 phase motors   only put out around 2/3 of there rated hp with a phase converter?

It may be dependant on the phase converter and how well it's balanced (phase to phase - not mechanically). I've been told that our Ronk converter is 95% or better efficency. Also there is the problem of power supply fluctuations.  Some days and some times during the day, the power fluctuates.   But I'm sure the loss is no where near 33%.

ElectricAl's variable speed frequency drive should clean up all the voltage variations and provide balanced and constant power despite power fluctuations.

[Al_Smith]

It gets a little confusing to explain .Now I know how things go because that's how I make my living but explaining it is not all that easy .

Here goes though .A phase rotary converter is about 92 or more percent efficient just like a three phase motor .Properly made they are or produce a true three phase output .It is not rocket science because I've made about 20 of them .

As far as WM motors they don't have the market cornered on electric motors .They do make a good product though .

Reduced voltage starting of electric motors is nothing new either .It's been used for probabley at least 100 years if not longer .Now of course modern "soft start " device seem to be the ticket but it's not the only method .

Google terms like "wye start delta run " or reduced voltage starting on polyphase motors .Compensator or part winding start would be another .Google can explain it better than I can .

The DC drive lifts assembles on that converted saw would operate very easily on a 12 volt battery with a battery charger as has been afore mentioned .

[Al_Smith]

Another junk yard dawg thing .WM 25 HP motors that they mentiond could produce up to 70 HP are nothing more than a surge it could with stand for a short period of time .Any motor can do that with time activated overload relays .

Motors are rated with a service factor which is figured on design HP .For example a 10 HP motor with a 1.25 service factor can run with a 12.5 HP indefinately without burning up .Now obviously that 25 HP producing 70 could not withstand a load like that very long .However say you hit a big nasty limb with a bandsaw it could probabley muscle through it before it tripped the over loads .If they were bypassed all the magic smoke would leak out .Once it's gone it's gone never to run again --boat anchor  ;)

[ElectricAl]

Bandmiller2,

I have seen other machines with 2 small electric motors. It seemed to work.
However 2 small electric motors would not work for us.
Our customers can see our sawmill from where they park.
They judge us on our equipment, so we try to keep the equipment looking good.

[Bibbyman]

I looked up the weight, a 10 hp single phase is 140#, so that would be 280 or a little less than a 3 cylinder diesel.  Also I'm not sure but don't 3 phase motors   only put out around 2/3 of there rated hp with a phase converter?

About motor weight. The largest engine I'm aware of that was used on the 93 mills was the 24 hp Onan gas engine.  I'm not sure when the WM mills were first available with diesel engine.  The Supers have much larger up/down motors.

[Larry]

Also I'm not sure but don't 3 phase motors   only put out around 2/3 of there rated hp with a phase converter?

Just to clarify.  A static phase converter uses a capacitor bank to start the motor than a relay cuts the capacitors out.  This will run a 3 phase motor at 2/3 (or less) only.  A rotary phase converter has a motor which generates the third leg and will put out over 90% of the power required.  They can be tweaked to put out almost as good as utility power.

I thought WM used soft start motors on the mills.  I guess not or Al wouldn't have needed the VFD or maybe something I don't understand.

[Bibbyman]

The motors on Wood-Mizer mills are soft start.  ElectricAl had major issues with incoming voltage that the power company would not or could not correct.  If we had to start from scratch again,  I'd go with the variable speed frequency drive over the roto phase converter even at the higher price. 

I don't know if Wetdog has said if he has 3ph or if he'll need a converter.

[wetdog]

The motors on Wood-Mizer mills are soft start.  ElectricAl had major issues with incoming voltage that the power company would not or could not correct.  If we had to start from scratch again,  I'd go with the variable speed frequency drive over the roto phase converter even at the higher price. 

I don't know if Wetdog has said if he has 3ph or if he'll need a converter.

I'll require a phase converter. I was considering one of the rotary converters.

[Bibbyman]

In my opinion,  the variable speed frequently drive like ElectricAl has installed is the best way to go. But also more expensive (maybe? ) 

The next best way would be a roto phase built for your application by a company that specializes in building them. Our converter came from Ronk.  They interviewed us as to the application and future use, etc. and made the recommendation.  They worked directly with Wood-Mizer and between them recommended the wiring and fuse size, etc. I think in my case it was money well spent. It's been in service 11 years.

The third way is to become your own expert and assemble your own roto phase system. A lot of guys do it. I didn't feel confident or competent enough to do it myself.

One other thing to consider is future expansion.  As I understand it, a VSFD will work for only one motor.   We have added an edger, jump saw and hydraulic pump to the same roto phase system.  The rule is, the roto phase hp rating needes to be twice as high as the biggest motor.   Our biggest motor is 25 hp so our converter is 50hp.  That means we can run more than one motor at a time up to a total of 50 hp.

[Dave Shepard]

You also need to make sure the RPC will start the motor you are using. Bibby's 50 hp will probably not start much more than a 25hp motor.

A VFD will still need 3 phase in, won't it? They aren't the same thing as a static phase converter.

[Bibbyman]

You also need to make sure the RPC will start the motor you are using. Bibby's 50 hp will probably not start much more than a 25hp motor.

A VFD will still need 3 phase in, won't it? They aren't the same thing as a static phase converter.

That is correct about max my converter will start. But it'll run up to 50 hp. So far, that's been plenty. If I had planned on a lot of other 3ph equipment at one time, I would have needed a larger unit.

That is incorrect about the VSFD. At least the unit ElectricAl has.  It takes dirty 220 single phase and makes quality 3ph at any cycle you want. In that way, you can adjust the rpm of the motor. He can adjust the motor rpm down to 60 rpm if he wants.

[customsawyer]

I am listening you guys just keep talking. :P

[bandmiller2]

There are a lot of instructions on the net to build rotary and static three phase converters.If you have an amp probe a bunch of capacitors and patience the legs can be balanced quite close.I have run a milling machine for 40 years with one I built and I'am no Tessler. Frank C.

[ElectricAl]

Bibbyman is right about our crappy incoming power. Basically we don't have enough Current at start up. Some call it, In Rush Current.

By using Inverter Technology the system can start the 25 hp motor without causing voltage and current drop on the Service Line side. 

Another huge plus to the VSFD is we wired and programmed it to Idle the electric motor. 
We chose 90 rpm as our Idle speed. 90 rpm is where the Alternator drops to 14 volts for charging.
By using the WM Auto Clutch we disengage the blade and idle the motor. When the Auto Clutch is
engauged the rpms ramp up to full speed in 3 seconds.   The benefits to this is not burning the belt when the clutch is disengauged.

Now the down side to a VSFD is it can only power one motor at a time. But the VSFD could power several machines if only one is used at a time.

Oh ya, it is quiet. Just a light humm.  Our florescent lights make more noise.
We added a green light to the control box to show that it is still ON .

[Al_Smith]

You also need to make sure the RPC will start the motor you are using. Bibby's 50 hp will probably not start much more than a 25hp motor.

A VFD will still need 3 phase in, won't it? They aren't the same thing as a static phase converter.

A rotary will start up to it's rating .If it's a 10 HP it will start a 10 Hp but it will run up to about 3 times it's rating .

Tell ya what I did .First of all I'm somewhat of an electrical mad man,keep that in mind . ;)

When I built my 5 HP convertor I over capacited it .It's got a 2200 MFD start cap .One of my lathes ,the Bridgeport mill and one drill press have maintained contact start  switchs .Just to see what would happen one day I started not only the convertor but an additional 6.5 HP of other motors all at the same time .Never even dimmed a light .

[drobertson]

Al, that sounds good! I may be picking your brain in the days to come,  thanks,, david

[Larry]

Al, who do you call when the VFD breaks?

My home built pony start 10 HP rotary phase converter will start another 10 HP motor lightly loaded.  It will not start that same 10 HP motor when I put it on the air compressor.  It trips the breaker on the single phase side.  Sizing the phase converter at double the driven motor size is just good business.  A rotary phase converter can be configured with a second idler motor.  By doing this much larger loads can be started.

I put a lot of work but not much money into my converter.  Tweaked the 3-phase output with capacitors so that it is good nuff to run a cnc milling machine.  It was fun building and I learned a lot from the experience.



It has a big box on the back side for the capacitors, control transformer, and distribution blocks to feed a 3-phase breaker panel.

I also have a couple of smaller VFD's in the shop.  They work great for their intended purpose.  I'm looking to buy a small sensorless vector control (provides constant torque require-less of rpm) VFD.  It requires the operator to program plc functions using ladder logic...I'm learning but not even close yet.

[bandmiller2]

Larry,is that red button in the middle to start your rotary converter,just to give it a momentary boost to start turning.?? Frank C.

[bandmiller2]

Question for "thems that knows"or  at least know more than me.If you have a big motor or rotary converter and startup really drops your voltage,would this help.Have a smaller motor you could pivot onto the big motors belts to get it turning and almost up to speed then hit the switch. Frank C.

[Larry]

Frank, that red button is painted green now.   It is a monetary button that turns on a small single phase pony motor.  The small motor is belted to the 3 phase motor.  When the 3 phase motor is up to speed I hit the other green button on the starter which puts power to the 3 phase motor.  No amp surge at all when it starts. 

[Dave Shepard]

Al, the factory made RPCs that I have looked at do not show that they will start their maximum capacity. One of them is a 60 HP unit, but will only start 20 HP according to the tag. Also starting another smaller motor first and letting it idle before starting a big one is a trick some people use when they need a little more capacity from their converters.

I like the idea of the VFD on the electric mill and the autoclutch. That's what WM should use on the LT70 AC. Not having a clutch is a bad idea, unless you are not on a demand meter.

[ElectricAl]

Dave,

On the Ronk Phase Converter that Bib and I have, it is rated at 50Kva and will start a 25 hp motor.
It will run a total of 50 hp combined motors.

Now the unit you are looking at is a 60 Kva and can only start a 20 hp.   I'd look else where.
There is some sort of electrical or mechanical short comings.

I think we paid $3500 for the Ronk years ago.


ElectricAl

[Dave Shepard]

This isn't one I'm buying, I was just looking at the plate on it. Somebody else bought it. It was basically a 60 hp of bigger electric motor. It was a brand name factory made unit. Maybe Rotophase. So you are in the same ball-park, you can only start a fraction of the rated load capacity, not 100% like Al Smith said. Perhaps the RPC I was looking at should really be called a 20 HP rated, as it will run three times what it can start. I just know that it had 20HP start/60HP run rating.

So you are running an RPC, then using a VFD to run the motor? So why is Bibbyman saying you are taking single phase and putting it into the VFD and getting three phase out? I'm not saying you don't have one that can, but any VFDs that I have had dealings with were simply to control motor rpm by varying the frequency, and were strictly 3 phase in, 3 phase out. Just looking to better understand the situation.

[ElectricAl]

Dave,

We have the Ronk RPC for the Morgan Edger and the Challenger Mulch Grinder.
The VSFD is for the LT50HDE25.
Both are feed 220 volt single phase.


Plus we have 2 Electric Stihl chain saws and a Toyota Electric forklift.

Hence the user name ElectricAl   ;D



ElectricAl

[Al_Smith]

Couple comments .On a compressor if it does not have a head pressure unloader it will start almost under full load . Huge starting  load if that's the case .

Now pony crankers on rotarys are usually put here because people don't know how to size the capactors.

The very last rotary I built which is a 10HP is now residing in Mich running a 10HP punch press and doing well .That one has a 1500 micro farad start cap and running balance caps so phase to phase is within 2 volts .

Okay now then say you built a rotary without balance caps for 240 volts .Once it's wound up with no caps you might have an inductive lag on the dummy phase and only have 200 volts .Once you throw in a big motor to start it might drop to 180 or less .That would be about like single phasing the motor.No wonder it wouldn't start .--more --

[Al_Smith]

Okay here's another thing .If you are really concerned about a balanced load you can add running caps to the indvidual motors and get them really well balanced as far as equal voltage on all phases .I never really worried about it myself .

Now VFD's .Some or maybe all of them rectify single phase to DC and actualy act like a static inverter to make the 3 phase .For what they are the are fine .I can't say I'd be a fan of them for making 3 phase though but that's just my opinion .--everybody has one --

At work we have giant multi thousand dollar VFD's but they are 3 phase .I mean you could by a decked out Cadillac for what they cost .

[bandmiller2]

Larry,the reason I asked about the button is my 5hp converter is capacitor started.When I want to start I flip a knife switch and just bump the push button momentarily that gets the converter rolling.Years ago I'd just wrap a small rope on the shaft and pull like starting a lawn mower. Frank C.

[Al_Smith]

 :D Well actually that rope start deal works .It does okay as long as the phase converter motor and the driven motor are connected and running .However if you disconnect the converter from the load for any length of time it will over heat  because of the dummy phase having no place to go except make heat .Which is why it's best to use running caps on the dummy phase to prevent that .

Say I took the liberty at work today to cruise flea bay .They have conversion kits to wire a motor for a  rotary for a pretty good price .Not large ones ,5 and 10 HP I think .