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Thread: Is three phase really a benefit for our use ?

  1. #1
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    Is three phase really a benefit for our use ?

    Are three phase motors an asset or liability for our small shops ? I know it is beneficial in a production shop, but how about our hobby shops ?

    I just spent close to $400 powering up my new to me 3 phase 5hp jointer. The machine runs well and strong. I push the switch and it spins up. It would do that with a single phase motor though.

    What did I gain by getting a 3 phase machine ? The jointer was what I was looking for and the price was right for me. I had anticipated that buying a used jointer in the size I wanted would entail 3 phase so I am not complaining. Just wondering why so many people consider 3 phase a plus.

    BTW, Matt Matt was an unbelievable amount of help programming the new VFD from Jack Forsberg. I was totally new to VFD's and knew nothing about programming them. After close to two hours over several different phone calls with Matt on a Sunday afternoon I believe I could now program one out of the box unassisted. Matt's explanations are that easy to understand.

    Bob

  2. #2
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    Three phase on a jointer or tablesaw is pretty much no benefit. rotary converters have no real advantage over single phase.
    VFDs allow slow start and variable speed of three phase motors but you need one for each machine. A three phase motor should last a lifetime since it has no capacitors or switches to go bad.
    Bill D

  3. #3
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    I partially disagree Bill.

    On tablesaws, being able to motor brake is a nice feature. And no, I don’t mean stopping the blade in 1 second and no the arbor nut has never loosened. Spinning down in 3 seconds is nice though.

    There are quite a few old arn jointers that are direct drive (DD). Converting to belt drive and a single phase motor doesn’t make much sense. So, keeping 3 phase in this case is almost a no brainer.

    So what do you gain by keeping the machine 3 phase OP? A smooth running bombproof motor that will last a lifetime. Question - how old is the jointer? Did you replace bearings or at least inspect the motor? I ask because I do this on all my vintage motors - the amount of sawdust that’s usually packed in there is amazing, and sometimes you find things like lollipop sticks and bathroom notes in school machines.

  4. #4
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    Quote Originally Posted by Matt Day View Post
    Question - how old is the jointer? Did you replace bearings or at least inspect the motor? I ask because I do this on all my vintage motors - the amount of sawdust that’s usually packed in there is amazing, and sometimes you find things like lollipop sticks and bathroom notes in school machines.
    The jointer I bought is only four years old and still a current production model. Oliver 4240 and did not even have any scratches on the paint. It also came with a Byrd head that the cutters had not been turned. Although the first three or four rows of cutters against the fence are showing their age. If the rest of the cutters were not in such good shape I would have turned all of them. I also got the original straight knife head and knives in the shipping box the Byrd head came in with one of the original bearings still on the shaft. This bearing is still smooth and tight enough I could put it on the machine.

    I agree about the 3 phase/VFD braking ability. I have the jointer VFD set up for four seconds spin up and spin down. That would be nice on my table saw to not have to wait whatever my Powermatic takes to stop spinning so I can clear a thin drop next to the blade.

    Bob

  5. #5

    Cost? VFD?

    I'm curious about the money if you're willing to divulge. I think this is a 10" jointer that costs around $3200 + shipping + the helical head.

    What were the steps and costs involved in converting to 3 phase?

    1. Did you re-wire your panel (or sub-panel)?
    2. Or is the 3 phase/VFD (Variable Frequency Device) a gizmo to avoid that? And is that the $400 cost?


    Thank you. And congratulations on your acquisition - it would seem to be quite magnificent.
    Doug, the "Wood Loon"
    Acton, MA

    72, slow road cyclist, woodworking dabbler, tool junkie , and
    bonsai enthusiast.
    Now, if I could just stay focused longer than a few weeks...

  6. #6
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    A lot depends on what you make. I tend towards larger stuff, 8' doors, heavy moldings, 12,4 stock or even heavier. Three phase is a no brainer because for the cost of vfds- 200-400 per machine, rpc-2000, or phase perfect 4000, you have access to industrial machinery. A guy here just posted his new Griggio slider- probably 14K new- that was like new for under 4K. My 20" SAC planer was 4K, my SCMI T130 sliding table shaper that had never been used was 4K. I've bought 40-50 used machines for a fraction of what new of lesser quality would cost. Last night I jointed some 15" wide oak for a friend that was so out of whack I needed a 1/8" cut to flatten it out in a reasonable time. The 5" thick stuff was then straightlined on a 9 hp saw. That kind of work is hard on the build of most single phase machines as they seldom are made to handle more than a 5 hp motor. Even the 7.5 hp single phase stuff is the same build with a larger motor stuffed in.

    If you tend towards bigger projects, don't have the time to fiddle with multiple passes ( I've never liked doing finish cuts ) or just enjoy well made machines, three phase is a necessity to be efficient with your time. Dave

  7. #7
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    Quote Originally Posted by Doug Hobkirk View Post
    I'm curious about the money if you're willing to divulge. I think this is a 10" jointer that costs around $3200 + shipping + the helical head.

    What were the steps and costs involved in converting to 3 phase?

    1. Did you re-wire your panel (or sub-panel)?
    2. Or is the 3 phase/VFD (Variable Frequency Device) a gizmo to avoid that? And is that the $400 cost?
    Here is the story. I am a hobby and craft woodworker. Only jointer I had ever owned was a ~1960's Homecraft 4" model in spite of owning some really nice commercial grade other machines. About a year ago I started looking for a used 12" jointer with a $1500 max price. Passed up a couple because they were 3 phase went to look at one that was converted to single phase ( hack job ). Gave up a few months ago and ordered a Grizzley 8" straight knife model even though I was not completely happy with my decision because I really wanted one bigger.

    While waiting for Grizzley the BO status went to late August maybe September. Started looking used again and a 1982 vintage Taiwan 12" single phase short bed one popped up for $600 all rusty and dirty but the owner said it worked fine. I thought this would be a fun project to rehab and told the owner I would be there Saturday to look at it. Then the Oliver popped up in Fort Lauderdale, 600 miles round trip. Too far. Next day at work kept thinking about the Byrd head and 84" of tables. Called the owner and felt comfortable the machine was almost like new. Told the owner I would take it, without even laying eyes and hands on it.

    The money breakdown.
    $1650 for the machine.
    $160 gas to go after it.
    $40 Home Depot trailer rental
    $385 USD for the VFD
    ~$75 wiring (did not keep track of )
    Two hours to convince the neighbor with rigging experience, lifting straps and a shop crane it would be a fun trip to see Fort Lauderdale.

    That is close to my self imposed budget of $1500, isn't it ? This is probably one of the reasons I am divorced.

    For the wiring rather than running a new circuit I put a cord and plug on the VFD and used the existing MIG welder outlet. Then I ran another cord and plug from the VFD to the jointer which already had a 20 amp four conductor plug in it when I bought it. I mounted the VFD up high on the wall out of the way so it would not get bumped, banged or otherwise. The VFD is hooked up with three conductor 10 gauge SO cord plugged into a 30 amp circuit outlet. The wire going to the jointer from the VFD is 12 gauge four conductor SO cord. I included plugs so I could unhook the jointer and move it out of the way when not needed. I will make a mobile base for it as soon as I figure out how to put swivel casters under a ~850 pound machine without raising the table height too much.

    To answer your question 2, yes the VFD in this situation is a phase converter. That is single phase in and three phase out. The other things the VFD is capable of are simply added benefits for what I am using it for. Variable speed and timed spin up and spin down ( braking ).
    Last edited by Robert Hayward; 06-03-2018 at 12:51 PM.

  8. #8
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    Robert, did you wire the vfd just to the jointer's power?! The start and stop buttons on the jointer need to be wired to the inputs on the vfd to control when to start and stop the jointer. You do not put a switch on the line output side of a vfd. You are risking blowing that vfd with a voided warranty to boot.

  9. #9
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    Quote Originally Posted by Mike Heidrick View Post
    Robert, did you wire the vfd just to the jointer's power?! The start and stop buttons on the jointer need to be wired to the inputs on the vfd to control when to start and stop the jointer. You do not put a switch on the line output side of a vfd. You are risking blowing that vfd with a voided warranty to boot.
    Yes, that was all done properly under Matt Matt's guidance via phone.

  10. #10
    Quote Originally Posted by Robert Hayward View Post
    Yes, that was all done properly under Matt Matt's guidance via phone.
    Bob,
    Who is 'Matt Matt'?
    Thanks,
    Fred
    "All that is necessary for the triumph of evil is that good men do nothing."

    “If you want to know what a man's like, take a good look at how he treats his inferiors, not his equals.”

  11. #11
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    Quote Originally Posted by Frederick Skelly View Post
    Bob,
    Who is 'Matt Matt'?
    Thanks,
    Fred
    A member of SMC Matt Mattingley. Other than him helping me program my new VFD via phone I do not know him.

  12. #12
    Thanks Bob!
    "All that is necessary for the triumph of evil is that good men do nothing."

    “If you want to know what a man's like, take a good look at how he treats his inferiors, not his equals.”

  13. #13
    Robert, sounds like you got a great deal on a great machine. I bet you're quite happy that the Grizz was on backorder, now

    One question, though: do you use the VFD's on/off buttons, or did you run a separate wire from the VFD to use the jointer's original buttons (and, if so, did you put a plug on that cord, too)?

  14. #14
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    Quote Originally Posted by Dan Friedrichs View Post
    Robert, sounds like you got a great deal on a great machine. I bet you're quite happy that the Grizz was on backorder, now

    One question, though: do you use the VFD's on/off buttons, or did you run a separate wire from the VFD to use the jointer's original buttons (and, if so, did you put a plug on that cord, too)?
    Yes I did run a four conductor 18 gauge separate wire so I could use the buttons on the jointer rather than the VFD keypad to start and stop the jointer. I used a four conductor cable even though I needed only three wires because Matt suggested a spare would not hurt anything. While not on the control wire cord yet I am going to add a four pin plug as soon as I find one that suits me. I have a length of 1" heat shrink tubing in the mail that should be here Monday. I will use short pieces of the heat shrink tubing to tie the control cable to the power cable and put the plug in the same place as the one on the power cable.

  15. #15
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    For control wiring a modular phone jack has 4 conductors or the bigger modem jack has 6or 8?
    Bill D

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