25hp 3 phase bandmills

[BandsawWarrior]

Just curious if anyone is running their woodmizer 25hp electric off a rotarty phase converter?  If so what size converter are you using and has it worked well?

thanks,

[ronwood]

Bibbyman does. I believe it is 100hp

[Bibbyman]

Bibbyman does. I believe it is 100hp

This is one of those "believe on half of what you hear" things.  Yes, we've been running and LT40 Super with 25hp 3ph since 2002.  And we have a roto phase converter but it's only 50 hp. 

I have a long post about the phase converter in the "Knowledge Base" section of the Forum.  Just follow this link..

https://forestryforum.com/cgi-bin/tips/tips.cgi?display:1048263552-19768.txt

It has worked well.

[paul case]

100hp
50hp
25hp

sounds like bibby is running 175 hp to me.   :D  pc

[terrifictimbersllc]

he just said 500 how soon you forget

[Bibbyman]

To add to the subject...  ElectricAL and a few others run 3ph mills on a phase converter.

As an update.  Our mill has 4,800+ hours on it so I'd figure the roto phase converter has maybe twice that. As we sometimes run the converter to run other equipment - edger, jump saw, hydraulic pump.  Also, we turn the sawmill motor off when we're not actually cutting or not going to make a cut within say 30 seconds.  So the mill (and hour meter) is not running nearly as much as the converter.  We just crank up the converter and let it run until we're ready to take a major break or stop for the day.  The only maintenance we've given it is one pump of grease in each bearing once a year.

[brdmkr]

Bibby,

Out of curriosity, do you think you are getting the full 25hp out of your mill on the rotary converter?  Some time back, I was thinking about building one to take advantage of cheap used 3 phase woodworking equipment.  However, when I researched DIY converters, they all spoke of a fairly serious reduction in HP on the equipment.  Something about not being clean 3 phase (I can't remember).  I was wondering if the commercial converters may get around all of that.  If so, that might be a really cost efficient option in the long run.  You could run the mill and purchase industrial grade power tools fairly cheap.  I have been told that a 3 phase motor is tough to wear out.  It seemed like I priced some larger static converters and they were not cost effective. 

[BandsawWarrior]

Thanks for the link Bibbyman that was good to read.  I have a 40HP rotary phase converter set up right now to run our peterson with a 15hp motor.  I purchased a 30hp band resaw and I'm hoping it will run off the same set up.  I had Baker upgrade the resaw with a soft start and from what I read that makes it similar to starting a 15hp motor...I hope. 

My converter is a phoenix phase converter and they say I can run up to 90hp total but the largest motor I can start is 20-30hp.  I guess I'm going to find out. 

That was great to read your power consumption costs for your bandsaw...we did the same for our Peterson.
My electrician checked our amperage draw while our Peterson was running but not in a cut and we calculated our power costs at $.55/hour.  Or $1.05/hour in a cut.  Pretty amazing if you ask me!  That also includes the costs of the 40hp rotary motor of course.

[sgschwend]

You manufacture specifications sound off, not having them I would guess that:

Perhaps your converter is a 40 hp start with a much higher continuous hp rating.

Or the 90 hp reference is related to the over-current protection.

I know that many electric motor instantaneous current can be 2-4 times the average horse power rating of the motor.

[Bibbyman]

Bibby,

Out of curriosity, do you think you are getting the full 25hp out of your mill on the rotary converter? 

I really have no idea not having sawn with the same motor on real 3ph. 

There was some talk about losses involved in running the converter.  Maybe a couple of %. 

I know one time we complained to the power company that we seemed to have low voltage on the line from time to time.  They pooo-hawed us for a couple of months and complaints.  Then finally a lineman came out and check it when it happened to be running pretty good.  He said the voltage was within limits but bumped it up to the upper end of the limit.  Said he'd been telling them in the office that they had a problem with the tap changer in one of the substations but they didn't want to fix it.  They finally had to.

Besides, the hp rating on an electric motor is not the peak hp it will develop. It'll just keep pulling all the amps it can take until a fuse is blown or something else gives out.

[Larry]

However, when I researched DIY converters, they all spoke of a fairly serious reduction in HP on the equipment.  Something about not being clean 3 phase (I can't remember).  

You were reading about static converters.  They only produce 2/3 of the required horsepower at best.  Under heavy load conditions the equipment motor can let out the magic smoke.

Rotary phase converters are near the equal of power company juice.  A good rotary phase converter will have capacitors to balance the output to the load requirement.    Home built can be better than store bought because of this reason.  For example I'm right on top of the poco transformer and it provides me with 243 volts.  They can even be tuned to run CNC equipment.

The only drawback comes when there are big mismatchs between converter and loads.

[paul case]

i know this is highjacking but here goes.
i was pretty concerned about depending too much on electric at my mill. ours isnt off a lot but just over in mo (across the road) the current is off for up to 30 minutes 2 times a week. i didnt want the electric being off to stop me from sawing. does this slow down any of you electric sawyers?  pc

[Bibbyman]

does this slow down any of you electric sawyers?  pc

We're about a half mile from a main feeder line (it's 3ph but they want $45,000 to bring it to us.) so we're almost never down when it's anywere near nice enough to work.  The last real outage was when the ice storm came though fall before last.  We were out maybe 2 days but others were out up to a couple of weeks.

The only real problem we have is sometimes they must do some switching of the service lines to ballance a load or something and the electricity will go off for a a split second and then come right back on.  If nothing is under load,  it's no big deal.  But if you're in the middle of edging and the power goes out and then come right back on, the board you're edging will bind up and you'll have to stop the machine and hammer it back, etc.

I'll trade these small interuptions any day then go back to maintaining an engine!

[brdmkr]

Bibby and Larry,

Thanks for your answers.  Maybe it was the static converters that were having such a reduction in power.  It has been a while since I looked into it, and it would be easy for me to get things crossed.