Changing Wood-Mizer from gas to electric

Process and parts involved in converting an engine. February 19, 2002

I'd like to change my Wood-Mizer 91 gas engine LT40 to electric and set it in a permanent mounting. Does anybody have experience doing this? Did the whole control panel get replaced?

Forum Responses
From contributor A:
We made the change in 1997, after trying to deal with the exhaust for a year inside. We could not find any flex tubing that could take the heat of the exhaust. We ordered from WM a Baldor E15, conversion base plate, pulley and belt. Also, the head lift chain needs to be replaced with HD chain. We did also install a new Ronk roto phase. It's rated for 50 HP. This leaves us room to expand. The saw is 15hp and the edger is 10hp.

We went from $450 min/month for gas to $50 in electric at 10/kw. Now we are at .05/kw on time of day rate.

The E25 is too heavy for your saw head. The E15 is good enough for 90% of what you saw. Plus the E15 will out-pull an Onan 24. Electric pulls full RPM till it stalls, whereas gas bogs and bogs and bogs some more, then stalls.

What timing, contributor A?

We just put in an order for a new Wood-Mizer LT40HDE25 Super with 25hp motor. We have single-phase power and are talking with our REA to bring 3ph 6/10 of a mile. They want more than the new mill to bring it just that far, so we are looking at rotary phase converters.

I got the electrical wiring specs for a rotary phase converter from Wood-Mizer and started calling around. Our local Crescent Electric dealer gave me a really good price on a 50kVA Ronk Add-A-Phase phase converter. Said they were having good luck with them. What has been your experience with the Ronk rotary phase converter – installation, maintenance, reliability, cause spike on line when turned on, complaints from utility, etc?

I remember reading a warning from Wood-Mizer not to remove the axle and tire assembly from your mobile mill to make it stationary. They say there is a danger it may tip over when a log is loaded or turned. Need to get a conversion kit for the leg supports to spread out the weight. Guess you could make your own outriggers but just something that may need attention.

Also, we “converted” our 96 LT40HDG35 Super to electric by finding it a new home in Arkansas and promptly calling Wood-Mizer to build us a new one with all the goodies.

From contributor A:
Your electrician must know about manufactured 3PH. Also, never hook a magnetic contact switch to the WILD leg.

It's been smooth sailing with the Ronk. When you hook up the new saw to the 3 legs, start it and check the amp draw on each leg at the saw. If one is way high or low, switch the leads around until they are as close as possible. The phase converter is well worth the investment. The best part about electrophing is hard pulling steady power.

The photo is for an idea of how to hang the cable. We used barn door roller track to carry the cable. Also, we added a rope from the saw mast the trolley so there is no pull on the cable.

One of the hardest habits to break was not starting the electric motor to put heat in the block. We switched in February and had sawn 5 years with gas. The other is a learning curve thing. Without a gasser bogging down, how hard do you feed the blade? You will hear a different sound coming from the blade when you get close to max. Yeah - the blade makes noise - you just never could hear it.

An electric edger would be nice if you don't have one.

You do need stationary legs and if you remove the axle, mount a block under the main tube where the axle was. The saw is a little tippy with big logs if you are not bolted down. We have radiant floor heat, so we are not bolted down.

From contributor A:
The starting of the roto phase is like starting a 5hp E. The E25 is a different story. You may have to go to a soft start. Call WM for a sawmill electrician and ask about the pros and cons of soft start.

Also, Ronk sends extra capacitors for starting. I don't remember the directions but we unhooked one or two to fine-tune the system.

We are 9 miles from the substation, and sometimes the power is weak at 108 v. per leg. You can feel it in the saw, so it's break time. It comes back up within an hour or so. The only maintenance we do is blow the dust out weekly. I've been told they don't like the cold. Ronk has a good technical staff.

We changed ours over a few years ago. A fellow gave us two 20 hp 3600 rpm motors. We didn't change anything in the WM control panel. The key now just controls all 12V and has nothing to do with the electric motor. We installed a pushbutton control panel in the back of the shop. Inside are magnetic starters for each motor. The first starter we bought new cost $500. We found a used edger. We used a wooden spacer block to compensate for size differences between the gas engine and the electric motor, and just used the same belt. Instead of an alternator, we are using a battery charger sitting where the gas can used to sit.

Lucky for us, the power company installed 3 phase at no cost. There were existing transformers about 100 yards away. If I could find it, I would use used equipment as much as possible. We went to a sort of salvage place in Henderson, KY and saved $400 on a starter. I talked to WM during the changeover, and they were very helpful, even though I wasn't using any WM parts for this.

I changed my WM to electric about 11 years ago (main drive) and converted our remaining systems (up/down, fwd/rev, hydr, etc.) about 8 years ago. It was one of the best decisions I ever made. If you drive your motors with an AC inverter or vector drive, it will convert single phase to three (check with manufacturer for sure, many do) as well as give you a variable speed drive for your motor. This is great for fwd/rev. You can also set the length of time for the motor to come up to speed. This is great for up/down. Slow speed for close positioning and high speed for large moves just by holding down the button longer. They do cost more money than motor starters but are far more useful. And by putting one on your main drive, you can dial in the optimum blade speed for any application, as opposed to living with a compromise blade speed. Faster speed for small cuts, hence faster cutting and lower speeds for big cuts, where you need more torque and coarser sawdust.

Check with the REA about phase converts. The REA in southeast Mo frown on them. They want the $20,000 a mile to build new line. Have you thought about a generator? That is how I run mine. I have 3-71 Detroit and a marathon generator. Works well for me.

A 25hp 3 phase motor will require 100 - 110 amps for full load operation on 220v single phase, not counting the losses of converter. To start this motor will require about 400 amps! This means a 400 amp service to meet code.

The variable frequency drive and the soft start controls currently list for $3000 each from W.W. Grainger. They require 3 phase inputs. I would question if they will operate from a phase converter. The phase converters do not have a balance 3 phase output. (They do not have 120 degree equal voltage outputs.)

If I were going to install a motor using a converter, I would get a motor that could be wired to start as a wye and a delta to run. This would reduce your starting current. To tell how your saw is cutting, install a current transformer in one leg of the 3 phase and read the amperage. If you are drawing so much power that the line voltage is below 200 volts, your motors will overheat and have a short life. You should consider going to a diesel engine gen set.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor D:
In regards to the note about the torque of an electric motor and how it reacts to a load until it stalls, there is little reason for any electric motor to overload, unless a tooth gets snagged or you’re not running the proper load monitoring equipment.

In addition to electric being better, it’s also easier to take measurements on load dynamically while cutting. You can clamp on an AMP meter looks like a C shaped device that closes around a lead. With manufacture knowledge of how many amps are drawing when the system is about to overload you could easily set up a signifier either overload solid state or hydraulic instant backup or a simple light bulb that lights when your getting close to overloading for when your operating the saw manually. You could even set up a number of warning lights green for good. yellow for getting close, and red for pull back now. That way you will be able to insure your motor lasts longer.