Announcement

Collapse
No announcement yet.

Finished VFD mod to my lathe

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Finished VFD mod to my lathe








    Sent from my SM-G950U1 using Tapatalk

  • #2
    Cool.
    What functions did you assign to the stock buttons?
    Len

    Comment


    • #3
      I hope you are going to cover the resistor and terminations?
      Expanded metal works good for that.
      Cheers,
      Jon

      Comment


      • #4
        Originally posted by QSIMDO View Post
        Cool.
        What functions did you assign to the stock buttons?
        The jog button is set to forward 5hz, the E-stop to E-stop with 0.5 second Decel. Accel to 3 seconds, Decel to 2 seconds.
        Turned off Decel stall protection so it uses the external resistor.
        Where the flood coolant switch would go is the Pot for speed, 0hz to 120hz.
        The Apron mounted control lever is wired for Forward/Stop, Reverse/Stop operation.
        Used a Cat5 Ethernet cable for signals to VFD, used all 8 wires.
        Future additions, maybe a toggle switch to switch between maybe 3 second Decel and 1 second Decel for threading. Possibly another switch to turn flood coolant on and off.

        Sent from my SM-G950U1 using Tapatalk

        Comment


        • #5
          Originally posted by Jon Heron View Post
          I hope you are going to cover the resistor and terminations?
          Expanded metal works good for that.
          Cheers,
          Jon
          I should, doesn't even get warm doing a few E-stops. Think possible high voltage/current would be the bigger concern.

          Sent from my SM-G950U1 using Tapatalk

          Comment


          • #6
            Touching those will light you up big time. A perforated metal shield with a swarf cap is in order.

            Swarf shorting the resistor will take out your VFD braking system.

            Check your deceleration time setting with a heavy chuck, decent sized work-piece, and from high speed. It might not be able to handle that, braking resistor or not.
            Last edited by lakeside53; 06-12-2019, 07:04 PM.

            Comment


            • #7
              Originally posted by lakeside53 View Post
              Touching those will light you up big time. A perforated metal shield with a swarf cap is in order.

              Swarf shorting the resistor will take out your VFD braking system.

              Check your deceleration time setting with a heavy chuck, decent sized work-piece, and from high speed. It might not be able to handle that, braking resistor or not.
              Well, definitely have to address all of that. Of course I have to go back to work again...

              Sent from my SM-G950U1 using Tapatalk

              Comment


              • #8
                This is just an observation that might not apply. Feel free to ignore.

                I noticed that the resistor is mounted by way of caps on both ends. I thought that one of the cooling mechanisms for a wire wound resistor is the air moving (via convection) through the middle of the tube. It seems that the end caps will interfere with that.

                Dan
                At the end of the project, there is a profound difference between spare parts and extra parts.

                Location: SF East Bay.

                Comment


                • #9
                  Holy cats! That will take care of any cats. Of course you won't need them because it will probably eventually get the mice too. I guess that assumes they are using the lathe.

                  Is it possible for swarf to bounce down there, and into the motor fan?

                  Btw, nice work.


                  Originally posted by RB211 View Post
                  Last edited by Glug; 06-12-2019, 08:23 PM.

                  Comment


                  • #10
                    Swarf will get everywhere but the rear splash guard protects the motor pretty well. The cooling fan on the top of the cabinet is guarded and filtered.
                    I'm wondering how high the voltage gets on that resistor, maybe 300v. It's only active for three seconds or less at a time.
                    The kind of work I do is never on anything massive, but you know how that goes. This week I had a job that exceeded my Bridgeport's Z height... Maybe in two weeks I'll be turning something that weighs 300 lbs at 2000 rpm and have to hit the E-stop... Probably melt the wires.(which are high quality USA made)

                    Sent from my SM-G950U1 using Tapatalk

                    Comment


                    • #11
                      You know you can buy terminals blocks that fit on the DIN rail? Avoid use wire nuts all together.

                      https://www.digikey.com/products/en/...9?k=din%20rail
                      https://www.alliedelec.com/product/e...E&gclsrc=aw.ds

                      Comment


                      • #12
                        Originally posted by reggie_obe View Post
                        You know you can buy terminals blocks that fit on the DIN rail? Avoid use wire nuts all together.

                        https://www.digikey.com/products/en/...9?k=din%20rail
                        https://www.alliedelec.com/product/e...E&gclsrc=aw.ds
                        If you look closely, you'll notice that I used quite a few DIN terminal blocks in both cabinets. The bottom cabinet could use some for the grounding wires. The left most cable was too short to feed it directly into terminal blocks, hence why there's wire nuts at the top. Not ideal, could just run all new wires like I did with the front panel, might just do that.

                        Sent from my SM-G950U1 using Tapatalk

                        Comment


                        • #13
                          Originally posted by RB211 View Post
                          Swarf will get everywhere but the rear splash guard protects the motor pretty well. The cooling fan on the top of the cabinet is guarded and filtered.
                          I'm wondering how high the voltage gets on that resistor, maybe 300v. It's only active for three seconds or less at a time.
                          The kind of work I do is never on anything massive, but you know how that goes. This week I had a job that exceeded my Bridgeport's Z height... Maybe in two weeks I'll be turning something that weighs 300 lbs at 2000 rpm and have to hit the E-stop... Probably melt the wires.(which are high quality USA made)

                          Sent from my SM-G950U1 using Tapatalk
                          Depends if the active device is sinking or sourcing. If sinking (i.e. the "switch" is to the common) the full dc voltage is present whether braking or not.

                          Comment


                          • #14
                            Just piling on, I know, but the terminals of the resistor are normally hot with the bus voltage. You want that covered up.

                            The resistor ventilation thru the center will not be an issue in stop duty. the resistor is commonly mounted just as you have done. Plus, there is a duty cycle setting in the VFD, which is normally co-ordinated with the resistor wattage according to a formula that the instructions ought to have.

                            The braking resistors are often overloaded by factors up to 10 or more. it is the duty cycle that determines heating. A 250 watt resistor, if made for the purpose, can take 2500 watts 10% of the time and that equals 250 watts average. The only caveat is that the 10% cannot exceed the "integration time" that the mass of the resistor provides. So on time 5 seconds out of 50 is likely to be OK, where 5 minutes out of 50 would not, because the resistor would cook in 5 min on time, where it would not in 5 seconds on time. But stopping a lathe etc does not take 5 minutes, and usually not 5 sec even.

                            You do need a resistor of a type made to take excess current. Not every one of them is.
                            Last edited by J Tiers; 06-12-2019, 11:07 PM.
                            1601

                            Keep eye on ball.
                            Hashim Khan

                            Comment


                            • #15
                              The first photo looks just like my lathe, which is the Prince 13x40 from Jessey in Taiwan. Is yours the same? How do you like it?

                              Comment

                              Working...
                              X