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Three phase bandmill

Started by bandmiller2, May 15, 2010, 08:55:11 PM

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bandmiller2

Today I was real proud of my homemade bandmill.A guy dropped off an old dry white oak log 20" dia and 16' long.Heavy and hard but it cut true,the hydraulics turned it and the baldor 15hp had plenty of power.Its a real treat to have three phase from the utilities.Frank C.
A man armed with common sense is packing a big piece

Hilltop366

Nice Bandmiller

I would like to see the mill but I know you don't have pics in your gallery but has any one else put one on of your mill?

bandmiller2

Hilltop, I think member JSNH has a couple in his gallery.Frank C.
A man armed with common sense is packing a big piece

campy

Congratulations Bandmiller2.
Building your own sawmill is quite an accomplishment and one to be proud of.

I want to go electric because my mill stays in the same place.
Also, I don't care for the noise and fumes from my gasoline motor.

Our electric company does not offer 3 phase to my house.
Could I use single phase 220 and a converter?
How many amps would I need for a 20hp electric motor.
The thickest boards I ever cut are 25 inches wide and I cut them frequently.
Currently I have a 27 HP Kohler gas motor that does ok.
It does bogg down in these big cuts and I have to go slowly.

Any advice would be appreciates.

bandmiller2

Campy,you can run with a converter if you have a decent service coming to your mill.Several folks here ,best known bibby,have run for years with converters and would be better qualified to tell you about them.I installed my mill in place of anouther 3 phase mill all the wiring was in place if I recall there are 100 amp slo blow fuses.If I were going electric and wasen't sure of the service I'd look into a diesel 3 phase generator, big ones like whats used in hospitals fire houses est. can be found,used, reasonable probibly same as what you'd pay for a converter setup. With true three phase you could run everything plainers, chippers and the homested when the power is out.A 20hp three phase motor will handily replace your gas engine and then some. Frank C.
A man armed with common sense is packing a big piece

den

Make sure you have a large enough transformer, if you blow it you pay. I would think a 30 KVA would handle a 20 HP motor. Some transformers have the size in big numbers on the side.

Homelite SuperXL, 360, Super2, Stihl MS251CB-E, Sotz M-20 20lb. Monster Maul, Wallenstein BXM-42

bandmiller2

Anouther option would be to get one of those three point hitch 3 phase gen. driven from a tractor pto.Frank C.
A man armed with common sense is packing a big piece

J_T

Here our good old electric Co supply's the transformer . Already blown one they put up a 15kva i told them it might need to be bigger  ::) .They said if it didn't hold they would the next time . Am running a 25hp home built converter off a 100amp breaker got a 20 hp on a re saw a 5hp and 3hp on a Brewco low ride unscrambler another 2 hp on a small hyd. power pack . Re saw is shop built with electric power up and down with 1hp 1ph . have hyd. motor with a flow restrictor on the conveyor belt .

Have the power converter siting beside a 200amp power service got a 220 1ph starter moter mounted on the unit . Been cutting 4x6 oak into 4x4's lot of times we cut 200 hundred before shutting the saw off . Power converter is not shut down till we quit .   
Jim Holloway

Larry

Let's see...15kva is maybe good for 75 amps and how many amps does a 25 hp draw when started? :D :D

I'm building a new pony start.  Figured if I get the idler up to speed before I juice it, that will keep the excitement level low.
Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

campy

My electric company wants a LOT of money to run 3 phase into my home.

So, that leaves me with the 10hp single phase option.
Will that bog down in a 24" wide cut?

I don't mind slowing down because I have a chair I can sit in while the forward stroke of the saw is in progress.

Most of my cuts are about 14" wide in Walnut and Oak.

den

Homelite SuperXL, 360, Super2, Stihl MS251CB-E, Sotz M-20 20lb. Monster Maul, Wallenstein BXM-42

J_T

Larry that is correct . I wind mine real good or that 100amp breaker will trip fast on start .Got a hinge set up with the pony motor hooked on the frame once started i lift the motor up a tad turn the power off to it and flip the belt off .

Correct on the 75 amps  think they got a little for surge in it  ??? I didn't fill them in on details as they said you couldn't build a phase converter but you could buy one  ??? ???Maybe they think they are born or hatched  ::) According to my amp meter i am pulling 55 to 60 amps most times . When i get every thing else hooked up it will probably blow but our bunch is stubborn that way .

Campy build you a phase converter all it really does is supply a voltage for the third line by way of the motor windings . That is the simple way of putting it
Jim Holloway

J_T

Den you are correct there is some loss reason i am running a 20hp 3ph on my re saw it will break that blade and never grunt . Found too that some of the older motors were under rated on the tags but the amp probe will tell you. All my motors are from scrap yard or have been thrown away  ;D
Jim Holloway

den

The rating on a motor is full load amps (Sears...locked rotor amps) so if your not working the motor at it's max you won't get full amps reading.

If your using a static converter the capacitors are starting the 3ph motor (sends power to the dead leg)then it kicks out. Now your runing on 2 legs 66% power.
On a rotary (with pony motor)you have some power generated in the dead leg so you will get better then 66%.
Add capacitors from the other legs to the dead leg and you bring the % up , close to full rating.
Homelite SuperXL, 360, Super2, Stihl MS251CB-E, Sotz M-20 20lb. Monster Maul, Wallenstein BXM-42

J_T

Yep Off the third leg i get around 180 volts me and another guy been running these things for a few years . Have also found anything that will get the required volts up on that third line will work . Till my donated motors showed up i ran a 15 hp using a lot smaller motor for quite a while till i could get my 25hp set up . Don't know how long it would last doing this but i ran it for at least six hours a day sometimes longer for about thirty days .

I don't get in many these discussions  in this area as even the local power Co says it wont work  ::) So i collect all the spare 3ph motors that can't be run . When the transformer blew i moved all the evidence now i have the converter in a nice box drop a few wires and hook up my fan and keep my mouth shut when they put up the next one   ;D
Jim Holloway

bandmiller2

jim,I think your right about rotary phase converters not giving full power.I've run my milling machine for years with a rotary converter,it does the job but not with full power.Light duty its fine but something like an air comp. or sawmill that puts a load on the motor you should oversize.Theirs alot on the internet about converters and how to balance them with capacitors. Frank C.
A man armed with common sense is packing a big piece

bandmiller2

Campy,I believe a quality[not hong kong harry] 10 hp single phase motor with full voltage and a heavy service will do what you want.I would not try to run the SFPM band speed too high and not have any parisitic loads on that motor.I'am not sure of the comparison three to single phase horse power, should be the same.The 15 hp three phase on my mill has plenty of power ,it also drives a small hyd. pump.Frank C.
A man armed with common sense is packing a big piece

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