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Little VFD help please

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  • #16
    This machine was giving good service with an old on/off switch for 60 or 80 years.
    It have cut more stock than you ever will in your life...
    Does it really need VFD?

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    • #17
      This is a nice switch to put before the VFD http://ab.rockwellautomation.com/Mot...Motor-Starters
      I recommend fuses before the switch sized to protect the wire. You can set the VFD to run at power up. (When you flip the switch). You should set the overload parameter in the VFD to your motor size. If you can find the VFD model number I can help. I'm a controls engineer by day. Machinist pretender by night.

      --Mike

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      • #18
        Originally posted by Martin0001 View Post
        This machine was giving good service with an old on/off switch for 60 or 80 years.
        It have cut more stock than you ever will in your life...
        Does it really need VFD?
        No and yes. No to making it work better, yes to keeping the 3 phase motor when you don't have 3 phase power!

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        • #19
          Originally posted by garyhlucas View Post
          No and yes. No to making it work better, yes to keeping the 3 phase motor when you don't have 3 phase power!
          Gary, you beat me to it! I was going to say "no, unless I want to plug it into the wall and use it."

          Seriously though martin, this was just a cheaper way to get this 3PH motor running (already had been working great) on the power I have at my disposal.

          Mwooton. I'm headed back to the shop and will post specs ASAP.

          Thanks folks.

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          • #20
            Yeah.... I am a bit close minded, though in the countryside where I live 3 phase is taken for granted.

            Few years ago my friend from a city (where they are *singlephased*) was designing 100 A power supply (DC) without resorting to inverter tech.
            Poor guy have sketched some sad diagrams calling for 1F capacitor and other similar horrible items and asked me for advice.
            I had a look and I have found that there are only 4 diodes in his bridge rectifier and it was so obvious to me that there should be 6 of them... and then that horrible 1F capacitor would disappear for good and be replaced by a reasonable 1000uF or so.
            And with a custom wound transformer of little bit more advanced design 12 diodes would be needed, but the output current could be as DC as it possibly can get... and without buffer capacitor at all...
            But he was *singlephased*, so both of these options were closed to him.

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            • #21
              Ironically, when I lived in Brooklyn - 3 phase. Now that I'm in the country in vermo t...single phase. Little frustrating.

              I have the specs though:

              The VFD is a teco JNEV-101-H1
              The motor is a GE.
              1725/1425
              3/4 HP
              V=208-220/440
              A=2.6/1.3
              CX=60/50
              SF=1.0 (no idea what this is???)

              As best I can tell from the rats best, the motor was previously being run in low voltage.

              Thanks for all the help folks. Any advice on basic set up is much appreciated.

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              • #22
                If the saw isn't likely to see service 8 hours a day sawing heavy stock, I'd keep the switch and wiring, run it on 220 and just kick-start the 3ph motor with a capacitor and pushbutton.

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                • #23
                  Originally posted by Rosco-P View Post
                  If the saw isn't likely to see service 8 hours a day sawing heavy stock, I'd keep the switch and wiring, run it on 220 and just kick-start the 3ph motor with a capacitor and pushbutton.
                  Definitely not going to see 8 hours a day - but 8 hours ago I bought the VFD

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                  • #24
                    Originally posted by mwooten View Post
                    This is a nice switch to put before the VFD

                    --Mike
                    I wouldn't consider that a good switch to put in front of a VFD, that is more for on line starting direct with a contactor.
                    At first the motor could be started in the local mode with the keypad, but the contactor on the input and the stop start with remote buttons is the usual way.
                    Max.

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                    • #25
                      SF is *service factor*.
                      Here you have more about this animal:
                      http://www.engineeringtoolbox.com/se...tor-d_735.html
                      Value of 1 is in agreement with standards.

                      Here is a thread on this forum dealing with identical item to one which you want to install:
                      http://www.hobby-machinist.com/showt...ure-3-PH-Motor

                      As per my taste there should be nothing special about wiring.
                      Identify input terminals and connect these to your plug.

                      Identify output and connect them to your motor.
                      Output terminals will be marked as L1, L2, L3.
                      Your motor is most likely winded *in star* configuration, and because it is a low power one then it is unlikely to have neutral terminal connected to the centre of star.
                      So neutral terminal is to be used to secure safety earthing of the beast and there might but by no means must be some N terminal in the motor terminal box to facilitate that.
                      Sometimes 3 phase system has 5 wires with 2 neutrals, where one is neutral and second is safety neutral.
                      If so, then connect safety neutral to casing of the motor or to your machine.
                      It is nice to have machines earthed if some swarf get somewhere where it is not welcomed...
                      If you find that motor is rotating "wrong way around", then swap any of 2 live wires, eg L1 and L2, L2 and L3 or L1 and L3.
                      This will make motor rotating the right way.

                      It is simple really, but if you are in doubt, call electrician.
                      There is also an American-only problem, where the phase voltage is low (110V) and there are possibly 2 sets of outputs from your VFD device, the second set would allow to run European motors.
                      As you have found, your motor is working with such low voltages (~210V in 3 phase system is an evidence of that).
                      So you must identify the right set of output terminals from your VFD device.
                      Take multimeter, set it for a range of 500V and AC and check voltages.
                      Correct set of terminals will show ~110V between any live terminal and N and also about 210V between any 2 live terminals.
                      Incorrect set will show about 400V between phases, say between L1 and L2 and ~230 V between any of phases and neutral.
                      They should also be marked and documented in wiring diagram supplied with device.

                      I hope, that helps.

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                      • #26
                        Sorry max. It seems I'm getting more confused here. Are you saying I need something in addition to the VFD in order for this to work?

                        The switch that is on it was connected to both the wall outlet and then the motor. The motor would not have seen power prior to the switch being thrown (Dracula laughter soundtrack inserted here).

                        I had planned on removing the switch, taking power from the house into the single phase side of the VFD, and plugging the motor leads into the VFD.

                        Mentions here, as well as other research has shown up some options for relays, and now your mention of remote switches etc. if possible, I'd like to understand the bare bones way to get this to function safely (for both motor and me!), and then delve into the options.

                        Please forgive my ignorance. I'm Stumbling through this learning curve...

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                        • #27
                          I should also mention that unlike a lathe or mill, I really only need this thing to get going. The blade will take care of everything I need - as long as its moving. In researching this - I find post all referring to reversing direction ( which I thought I could do with swapping the leads to the motor), variable speed control etc.

                          Although these are all great functions for some machines - it's overkill for my needs. This thing will be cutting aluminum and steel, hopefully for a long time to come...

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                          • #28
                            Martin,

                            Thanks so much - you're speaking my language. Appreciate the link. I was just reading the same post when I saw I had a reply here. I will finish that up quick and see how much confusion it can't melt away

                            The VFD unit I have has only 1 set of outputs for the motor. I confirmed that it would work with the motor I have with the folks at dealers industrial.

                            While I totally understand the need for ground - I am not sure where the wire is for it on the motor. All leads coming from the motor seem to be spoken for and are connected as follows (matching the "low voltage diagram inside the motor cover):

                            T1-T7 together
                            T2-T5 together
                            T3-T9 together
                            T4,5 & 6 together.

                            The VFD definitely has a ground terminal for both the single and 3 phase side. Does it ground through this?

                            Not sure if this info/how to determine star vs delta set up.

                            I have a friend who will be checking this before I fry something. But if like to get it set up well before he gets here on monday. And of course, I'd really like to have a better grasp of this myself.

                            All your patience is much appreciated.
                            Last edited by motopreserve; 10-11-2013, 08:29 PM.

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                            • #29
                              Originally posted by motopreserve View Post
                              While I totally understand the need for ground - I am not sure where the wire is for it on the motor. All leads coming from the motor seem to be spoken for and are connected as follows (matching the "low voltage diagram inside the motor cover):

                              T1-T7 together
                              T2-T5 (?) together
                              T3-T9 together
                              T4,5 & 6 together.
                              Here you go:-



                              Cheers

                              .

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                              • #30
                                Originally posted by Barrington View Post
                                Here you go:-



                                Cheers

                                .
                                Thanks so much Barrington. Typo there - it was supposed to be T8. Damn iPhone!

                                This seems to make sense (yikes!). The only question now is where the ground comes from. On the VFD there is a place for a ground connection (PH). But I don't see a ground wire coming from inside the motor with the rest of the leads. Can I ground the chassis? Or do I need to get in there and dig around/install one?

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