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Trouble Shooting Toshiba Inverter/VFD VFS7S-2007UP

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  • Trouble Shooting Toshiba Inverter/VFD VFS7S-2007UP

    Hi,

    My Toshiba Inverter/VFD VFS7S-2007UP will power up but will not run the 1HP motor it was powering. The motor runs fine on a Phase Converter.

    I do not recall the fault code and will not be able to try it again, to get the fault code until tomorrow. Any advise about where and how to start checking it will be appreciated. I have a multi-meter and am comfortable doing routine voltage and resistance/continuity checks.

    Thanks,
    Bob
    Bob, 71193, Central Arkansas

  • #2
    The first thing to do is do a preliminary parameter set up based on the manual and motor plate details, then observe any error code, and whether it occured before running or initial fault..
    Max.

    Comment


    • #3
      Yes. It is quite important as to whether the fault is right away, or f it is delayed or maybe even happens later after the motor has been running.

      Also what was going on at and before the time of the fault.

      And, of course what fault, which usually gives you a huge clue where to look.

      For a delayed over current fault, might be accelerating a heavy load, try shortening the accel time if it is long, or lengthening it if it is pretty short.

      For an instant over current fault, wiring short (loose strand of wire is typical), or possibly even a bad VFD. The motor operating OK on RPC indicates it is not likely to be a motor problem, but it could be in any connections you had to undo to check it with RPC.
      Last edited by J Tiers; 07-06-2020, 08:03 PM.
      1601

      Keep eye on ball.
      Hashim Khan

      Comment


      • #4
        You can also use an ohmmeter to check for open circuit from the bus link (+) to each output (T1, T2, and T3), and from each output to GND. Then also in reverse you should read a diode drop (0.6-0.8 V) for the IGBT body diodes. You could also check for high capacitance from bus link (+) to GND, and maybe see if you can apply a DC voltage from a current limited supply. You could try applying an AC voltage from a Variac to the input to see if the bus voltage comes up OK. It should reach something like 280-320 VDC at 220 VAC input.

        [edit] Some of these checks may not be necessary if the unit powers up. But it could be a shorted or otherwise defective IGBT.
        Last edited by PStechPaul; 07-06-2020, 09:02 PM.
        http://pauleschoen.com/pix/PM08_P76_P54.png
        Paul , P S Technology, Inc. and MrTibbs
        USA Maryland 21030

        Comment


        • #5
          Max, I reset the parameters. It seems to power up normal. It try’s to start then trips out “OC1” code “over current on acceleration”.

          J Tiers, it happens as the motor is coming up to speed.

          Paul, your information is over my current knowledge level.

          I measured the voltage output voltage at the VFD and if correct got 185 to 186 volts for each of the three combinations.

          Bob
          Bob, 71193, Central Arkansas

          Comment


          • #6
            I'm pretty new to VFDs myself but 185-186v seems too low. That could cause an Over Current error on start up. I don't have the manual for mine handy but I seem to recall Voltage parameters somewhere. Check there first. I would think they need to be in the range of at least 205v or there about. I think mine are set at 220v.

            Comment


            • #7
              Ken,

              I thought 185-186V seemed a bit low also. I will be checking my manual.

              Bob
              Bob, 71193, Central Arkansas

              Comment


              • #8
                The output voltage to the motor depends on speed, so if it is rated 240 VAC at 3500 RPM it would put out more like 120 VAC at 1750 RPM. Can you measure the actual current going to the motor terminals T1, T2, and T3 during start-up? Also, some DMMs may not correctly read the PWM output of the VFD. An analog meter might be better for this purpose.
                http://pauleschoen.com/pix/PM08_P76_P54.png
                Paul , P S Technology, Inc. and MrTibbs
                USA Maryland 21030

                Comment


                • #9
                  Paul, I have a clamp on meter, so I will try measuring the current as soon as I can set up some separate conductors. I will try a analog meter on the voltage, those reading were using a DMM.

                  Bob
                  Bob, 71193, Central Arkansas

                  Comment


                  • #10
                    I wish quote would work for me. "The output voltage to the motor depends on speed" What motor are you talking about? I thought he was trying to get a VFD going. That's where the "output voltage" is coming from. I guess I'm confused.

                    Comment


                    • #11
                      OK, what is the acceleration time set to?

                      Is that trip-out when spinning up work, OR just the chuck, OR just the innards of the lathe with nothing else attached?

                      If the acceleration is set too fast, it can trip out, but often does it pretty early in the acceleration time. That is curable by setting the time to be longer. It is a parameter that you set, and it you did not set it, then it is still set for the default. You may need to change that.

                      If it is later, very possibly you have it set for a slow acceleration, in which case you are probably running out of "time vs current". The acceleration may be taking an overcurrent that is not too much, but lasts longer than allowed.

                      Background:

                      VFDs have an overcurrent detector which is time-sensitive. Often there is a listed 150% maximum for a minute or so, and there may be a listed short term (as in between say 2 and 15 seconds) 200% as well. Even if not listed, the higher limit exists,

                      So you might pull over the 150% but under the maximum for too long, and trip it. Or pull near the 150% for over a minute, and that also would trip it, although I do not think you have that issue.
                      1601

                      Keep eye on ball.
                      Hashim Khan

                      Comment


                      • #12
                        I wonder if it could be something like a dry bearing that starts galling at a higher speed. That should cause a distinctive sound, especially if you use a mechanic's stethoscope.
                        http://pauleschoen.com/pix/PM08_P76_P54.png
                        Paul , P S Technology, Inc. and MrTibbs
                        USA Maryland 21030

                        Comment


                        • #13
                          Well gentlemen, I have not yet been able to set it up to get set up to take current/amp reading yet. I did find a couple of suspect connections in one of the old rotary switches, this is an old Fray Vertical-Horizontal Mill, two identical 1 HP motors and switches.

                          Upon checking the voltages with analog meter I got running readings of 180-150-150V. The motors started and ran but with some clattering on start up and shut down.

                          I increased the voltage adjustment up and got running readings of 200-200-200V with less, but still some clattering. I have not adjusted it any higher since I have no understanding of how that effects the VFD and how common it is to make that adjustment.

                          It still ran smoother on the RPC.

                          Paul, I don't think it is a bearing they are recently replaced, felt smooth, and no issues on the RPC

                          Bob
                          Last edited by rwilliams; 07-08-2020, 01:36 PM.
                          Bob, 71193, Central Arkansas

                          Comment


                          • #14
                            I got amp readings, 1.9 on each line with the motor running, no high spikes during startup.

                            The VFD has two voltage boost parameters the one I mentioned increasing previously was #2.
                            Last edited by rwilliams; 07-08-2020, 01:36 PM.
                            Bob, 71193, Central Arkansas

                            Comment


                            • #15
                              1.9A on each leg still seems a little high. The total should be something like 4.8-5.1A. What's the motor data plate say for voltage? I'm guessing it says something like "208-230/460". Make sure the VFD is also set to 60-hertz. Both of mine came preset at 50.

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