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Trouble Shooting Toshiba Inverter/VFD VFS7S-2007UP

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  • #16
    When you speak of "adjusting the voltage", that suggests to me that you are not using the VFD "correctly".

    The VFD TAKES CARE OF VOLTAGE by itself. You tell it the nominal motor frequency (50 or 60 Hz) and the voltage the motor should have when at that frequency. BOTH those numbers come from the motor data plate. ou also program in the motor current, also from the data plate.

    Those numbers are not "options" for you to set wherever, unless you have the knowledge and a specific reason to do whatever you do as for setting the parameters.

    There is no need to "adjust" the voltage after the initial setup, the VFD will produce the appropriate voltage and frequency as it speeds up the motor to the set speed. That is what they do.

    Just perform the initial setup per the manual, and you should be able to operate the machine with the VFD and have everything work as intended.
    1601

    Keep eye on ball.
    Hashim Khan

    Comment


    • #17
      1.9 amps per phase seems about right for a 1 HP 240 VAC motor running at rated load and 94% efficiency. But it is more likely to be about 80% efficient and perhaps 70% power factor, especially when lightly loaded. So, depending on conditions, the current draw seems reasonable and should not cause an overcurrent trip.
      http://pauleschoen.com/pix/PM08_P76_P54.png
      Paul , P S Technology, Inc. and MrTibbs
      USA Maryland 21030

      Comment


      • #18
        1.9A is low for rated 1 HP 3 phase at full load 230/240V. It is not far off for an idling motor, no load. That's based on NEC rating of 4.2A at full load.
        1601

        Keep eye on ball.
        Hashim Khan

        Comment


        • #19
          Yes, I was going by theoretic calculations. 748 watts / ( 240 * sqrt(3) ) = 1.8 amps/phase. Here is a good chart of motor current ratings.

          Higher power motors have ratings closer to theoretical. For 230 VAC, 10 HP is rated 28 A, and 100 HP is 248 A. Typically higher efficiency and better power factor.
          http://pauleschoen.com/pix/PM08_P76_P54.png
          Paul , P S Technology, Inc. and MrTibbs
          USA Maryland 21030

          Comment


          • #20
            J Tiers; I misspoke earlier about adjusting voltage, what I did was adjust the Voltage Boost parameter and since set it back to the default value.

            Now the situation has changed about four hours earlier it was working but the motor was still not running as smoothly as when on the RPC. I was out and about for the four hours. When I returned and tried the VFD it faulted out with a "Overcurrent during Acceleration" code. It repeated this three or four times before I tried the RPC again; it worked fine.

            I appreciate everyone's help but I am finding logical trouble shooting this thing challenging, it seems old and cranky like me.

            Bob
            Bob, 71193, Central Arkansas

            Comment


            • #21
              Might have something about the tuning of the VFD. You drive does have an autotune feature and if something happened to change the characteristics of the motor that could be out of whack. I have had motors run like crud until I ran the autotune. Parameter F400

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              • #22
                Macona, I will give it a try tomorrow. Thanks,

                Bob

                Bob, 71193, Central Arkansas

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                • #23
                  It may be worth starting over by doing a "reset to factory defaults" then trying standard Volts/Hz mode, re-programming the basic stuff as directed in the manual. That will normally be motor rated voltage, motor rated frequency, and motor rated current, off the motor data plate, along with any other items the manual says are needed, if any.

                  Note what the acceleration is set to.

                  At that point it should "work". It may still have an acceleration trip, which you can try to fix by lengthening a short accel time (one less that a second or two). I do not think you would have a very long accel as a default, so that is not likely an issue.

                  The very first thing I would try is to run it with no motor, (or a very low power motor, if you have one) which it should do OK. If it acts OK doing that, then it is not an internal fault.
                  1601

                  Keep eye on ball.
                  Hashim Khan

                  Comment


                  • #24
                    Well, I have reset the parameters to default values and on a 1/2HP motor it immediately trips with an OC1, "Overcurrent during acceleration" fault, never got the motor to spin. I did one time come up with an OCA. "Phase short circuit" fault whose remedy was: "The main circuit is abnormal. Ask your agent to repair the inverter"

                    I know very little about electronics other than only touch one wire at a time and don't stand in water while doing it, learned at about the age of 9. But, this seems "broke" to me.

                    Bob
                    Bob, 71193, Central Arkansas

                    Comment


                    • #25
                      Might be worth taking apart and looking for something like a strand of wire or swarf in contact with a live circuit. If it has individual IGBTs (probably only older models) it might be possible to check them out and replace them. But unless you are really adventurous with lots of time on your hands, as well as skilled in electronics and have proper equipment, it's probably "toast" and time for the recycling bin.
                      http://pauleschoen.com/pix/PM08_P76_P54.png
                      Paul , P S Technology, Inc. and MrTibbs
                      USA Maryland 21030

                      Comment


                      • #26
                        Final test.

                        Remove all wires from the output (making sure that the motor was really connected to the output, it is surprisingly easy on some to revers in and out). Be sure to remove all strands of wire that might break off and lay across terminals.

                        Run the VFD with no output load. (many or most smaller ones will do that)

                        If it faults out with the OC code, the VFD is toast.

                        **********

                        Re replacing IGBTs...... Yes, this can be done in some, or in all if you can get the correct module.

                        BIG PROBLEM: Mostly, if the IGBT fails, it shorts to the gate, and blows out the driver chip as well. So in general, you replace both the IGBT that is bad, AND the driver chip. And then you hope that it did not "reach through" the driver chip and damage the control uP's output port, which sometimes happens.

                        If you do not replace enough stuff, the new IGBT may be blown right away.

                        On top of that, such faults often damage board traces, which may be buried inside the PWB itself, with multilayer PWBs, which are often used due to density of wiring.

                        Bottom line is that component level repairs are rarely worth considering
                        1601

                        Keep eye on ball.
                        Hashim Khan

                        Comment


                        • #27
                          Well I tried it with all output disconnected from the terminals. I still got OC1 and OCA fault codes. I am not capable or interested in trying any component level repairs so out it will go. I can't even find much for the junk drawer to salvage from it.

                          Thanks, to all.

                          Bob
                          Bob, 71193, Central Arkansas

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                          • #28
                            keep the capacitors.

                            Comment


                            • #29
                              Dian,

                              I was thinking about keeping the two large ones; so I will. It will give my sons and grandsons something to puzzle over in the future, maybe I should keep them half charged.

                              Bob
                              Bob, 71193, Central Arkansas

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