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  • GS2-55P0 repeat failure

    We have a problem with one of our macines repeatedly breaking down. Of course on a long weekend saturday.......

    Last year we installed a system containing a GS2-55P0 VFD on a 600V line to run a 2hp motor. We oversized the VFD to compensate for the frequent (15/hr) start/stop cycles this system will see. Note that this system is used in the fruit packing industry and only runs for about 6 weeks per year.

    After about a week of running, the VFD input appeared to have shorted out, taking with it the the Fuji 20A circuit breaker as well as the main disconnect 100A fuses in the process. The breaker would no longer reset and AutomationDirect was good to warranty the VFD and circuit breaker and we installed replacements and everything seemed OK.

    This year, on the first day, the VFD and breaker failed again, in the same manner.

    The panel also contains a Click PLC, C-More touch panel, a couple of contactors, and two ABB soft starters for two 30hp pumps, none of these components show any sign of damage. The pumps are protected with the same fuji circuit breakers and they work just fine.

    It should also be noted that we have another nearly identical machine with the same customer at another site which has been running for 3 years with zero issues, only difference is that on that unit we used a ABB VFD instead of the GS2.

    I have now replaced the VFD again, this time with a used GS2-52P0 that I had on hand and have ordered a GS2-53P0 as well as a line reactor as a replacement.

    Anyone have any thoughts what could be causing this problem? Anything else I could be doing to protect the VFD?

    Thanks for any help.

    p.s. Voltage into the panel is 610-612 Volts phase to phase, 60Hz


    Click image for larger version

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    Interior of panel, you can see the stain on the right from when the breaker blew the first time


  • #2
    I would guess first off there may be some weird rating stuff on input voltage for the GS2 rating. It says "575v" on the website, and I see in the specs the rated input voltage is "500-600v, -15%/+10%". That should mean the rated input is 660v AC. Normally I would assume that when something is rated for AC it should be rated for the nominal AC voltage like you would call it 480v, of 600v. But perhaps the GS2 is not rated as I would assume, since it does list that weird 575v on the web page and the specs list that specific voltage range. It *could* be possible then that the GS2 maximum input voltage is 660v (which would be weird since then it wouldnt accept a standard 600v line....)
    If your actual RMS voltage (reading from a typical multimeter) is around 610 volts AC, that means peak voltage is about 862 volts. So since the input keeps shorting out and causing an issue, the first place I would look is what the actual maximum peak voltage of the GS2 input is rated for as well as what the ABB you have in the other machine is rated for.
    Another thought I had would be that during startup of the machine there is some sort of voltage surge and the GS2 cant handle it but the ABB has enough protection to do so built in.
    Last edited by MikeN; 07-01-2019, 02:15 PM.

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    • #3
      I've checked. The ABB ACS250 VFD is rated for nominal 575V, 500-600V +/-10%, so 660V max rated, same as the GS2.
      Additionally, the used GS2 unit I've swapped in for now has been running in our shop for 4 years on 600V with zero trouble.

      The failure did not occur at the moment of startup, system was running for about a half hour while the refrigeration tech was there, checking his side of the system when it just decided to fail.

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      • #4
        Are you cycling input power to the VFD often? If so, the likely cause is the soft-charge circuitry which is not rated for that many power cycles. Just a thought...

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        • #5
          How long has the Power been removed from the drive? Some drives need to go thru a certain power-up procedure (to reform the drained capacitors) if the have been offline for more than a year. Perhaps the ABB drives handle that differently than the GS2.

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          • #6
            Originally posted by Levi G View Post
            How long has the Power been removed from the drive? Some drives need to go thru a certain power-up procedure (to reform the drained capacitors) if the have been offline for more than a year. Perhaps the ABB drives handle that differently than the GS2.
            This is true.
            If you have an urgent issue, please contact AutomationDirect's Technical Support team.

            AutomationDirect.com Technical Support: 1(800) 633-0405 or (770) 844-4200 Email Tech Support

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            • #7
              Are you cycling input power to the VFD often?
              VFD is powered in the morning and power is shut down at end of workday So 1 power cycle/day

              How long has the Power been removed from the drive? Some drives need to go thru a certain power-up procedure
              Power was removed from about October last year until June 24th, when I went to the site to instruct new operator on the machine. Ran machine for an hour without issue and shut it down.
              June 25th, Refrigeration tech fired up unit to do checks on his end of the equipment, drive failed after about a half-hour of running.
              No notes I saw in the manual about long-term storage powerup procedures on the GS2.


              *edit:
              We are considering adding a SPD such as this:
              https://www.automationdirect.com/adc/shopping/catalog/power_products_(electrical)/surge_protective_devices/ul_type_1_enclosed_(nema_type_4x)/stxr600y05n

              Panel is wired 3 phase delta,no neutral. Am wondering whether this 3 phase wye SPD would do or do I need to find another vendor for this (A.D. doesn't list a 600V delta unit)
              Last edited by Sterno; 07-05-2019, 11:57 AM.

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              • #8
                Originally posted by Sterno View Post

                VFD is powered in the morning and power is shut down at end of workday So 1 power cycle/day



                Power was removed from about October last year until June 24th, when I went to the site to instruct new operator on the machine. Ran machine for an hour without issue and shut it down.
                June 25th, Refrigeration tech fired up unit to do checks on his end of the equipment, drive failed after about a half-hour of running.
                No notes I saw in the manual about long-term storage powerup procedures on the GS2.


                *edit:
                We are considering adding a SPD such as this:
                https://www.automationdirect.com/adc/shopping/catalog/power_products_(electrical)/surge_protective_devices/ul_type_1_enclosed_(nema_type_4x)/stxr600y05n

                Panel is wired 3 phase delta,no neutral. Am wondering whether this 3 phase wye SPD would do or do I need to find another vendor for this (A.D. doesn't list a 600V delta unit)
                Could the refrigeration hardware be doing something to the power like causing significant distortions or a spike when the compressor turns off?

                Comment



                • #9
                  1. Frequent start-stop should not create any problem to the vfd. The vfd ramps up or down as configured, you could overload it if you try to accelerate or decelerate too fast, but for normal situations, the default setup should work fine. If you changed those ramp parameters, I say reset them to default. I would also set the overload current parameter to 115% motor FLA ( regular draw at rated speed/power) and if there was any overcurrent issue, the drive will stop. If this parameter is not set, then the vfd could fry the motor which in turn could short the vfd. I say there is a 40% chance this happened.
                  2. I would check if the vfd requires line reactor. I guess those are needed to protect the vfd by working reactive power back to the grid. I have never needed to use them but they are recommended on virtually any vfd. This line reactor comes inserted in grid-fuse-reactor-vfd-magnetothermal-moto contactor-motor.
                  3. In he picture I see a motor contactor atop the vfd but I donít see the fuse. Please refer to 2 for proper sequencing.
                  4. Please remember that the role of a fuse is to protect the power supply. You have power supplied from the grid and further from the vfd to be used by motor. So you need two sets of fuses.
                  5. Although that panel looks professionally build, the lack of fuses makes it unsafe. Please call back the panel builder to address the issue.
                  6. Any motor provides the rated power output at the rated speed, when the motor actually provides the max torque. If you turn the motor at lower rpm, the motor power output decreases faster than linear with rpm, because the torque output also decreases. Therefore you need a motor more powerful than what you read at rated rpm, because you run at a lower than rated rpm. For this reason, all electric motors are run at rated rpm and the reduction is via gearbox. Slight variations of rpm scale to large rpm changes at the shaft of the machinery, so the vfd still drives the motor close to rated output. You can still start and stop the motor via vfd, but the gearbox acts as a torque amplifier, allowing the motor to start slower but easier. As for stopping, usually the machinery drag does the job.
                  Last edited by Alexandru; 07-08-2019, 01:57 PM.

                  Comment



                  • #10
                    Originally posted by Sterno View Post

                    <snip>
                    Panel is wired 3 phase delta,no neutral. Am wondering whether this 3 phase wye SPD would do or do I need to find another vendor for this (A.D. doesn't list a 600V delta unit)
                    Delta input power is the likely problem.

                    Without a ground reference, any input filtering (R/C circuits and/or MOV's) have nowhere to discharge the power spokes they try to absorb. The answer, unfortunately is to install a 'Drive Isolation Transformer' which is wired Delta to Wye. The Wye connected secondary gets the center point grounded, thus you have a nice steady ground reference on each phase.

                    AD does not offer them, but here is one source: https://www.rexpowermagnetics.com/pr...nsformers.html

                    Comment



                    • #11
                      Delta wiring does have a ground, just that the ground is not equal distance from each leg (thus creating a "high leg" on delta configs). While there is a higher voltage leg, phase to phase is still the same voltage. Delta does have a ground reference just fine though. I dont know what each leg is on a 600v system, but for 240v phase A and C to neutral or ground would be 120v, and phase B would be 208 volts.

                      I have wired VFDs on delta input power and they work just fine, all of our production room is run on a 240v delta transformer. The power is just taking it from the 3 phases so it really doesnt know whether it is delta or wye, so delta wont be the problem in this situation for the OP.



                      As for the power filter, not sure if it will work or not. It says it is meant for Wye, and the high leg on delta may cause a problem, depending on how the circuit is designed, where it is constantly trying to suppress what it thinks is a spike every cycle of the power, which would be very bad.
                      Last edited by MikeN; 07-10-2019, 08:44 AM.

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                      • #12
                        Delta and star are modes of connecting electrical motors. They have nothing to do with drives.
                        all Ac drives are connected directly to phase lines plus neutral.

                        For electrical motors, delta connection reduces the winding resistance allowing for more current with translates at better starting torque. This while the same voltage is applied. Motor starters that commute delta-star take advantage of this.

                        motors are connected delta at lower input voltage and star at higher. Any motor that supports both delta and star can be connected star where delta is required, but will provide lower power. No motor should be connected delta where star is required because of risk of damage.

                        the Ac drive works this way:
                        1. The Ac power is rectified inside the drive and turned into dc
                        2. The controller generates the frequency
                        3. The inverter turns the dc back to Ac

                        There are two issues here
                        one is driving the motor. Understand that the motor produces the rated power only at rated rpm, and at lower rpm will not produce the same power. For this reason, the motor ramping should be carefully tested.
                        second is related to proper motor connection. Chapter 2 page 12 shows how is done, with a caveat.

                        the issue here is to wether the ground connection of the drive is tied to neutral of the electrical distribution panel.

                        The Drive manual presents the connection using ground as neutral. Is common in many countries because is cheap and saves one conductor, but it raises questions to who is responsible in case of a ground fault.

                        Have the drive connected as shown in the drive manual. If need be, acquire line reactors and insert them before and after the drive, as shown in the manual
                        have the machinery electrical panel certified to eliminate doubts about electrical connections.
                        have the Ac drive over current parameter limit the drive current output

                        I donít see the ground wire going from Ac drive to motor. Please make sure the motors are properly grounded.
                        Last edited by Alexandru; 07-09-2019, 11:12 AM.

                        Comment



                        • #13
                          Originally posted by MikeN View Post
                          Delta wiring does have a ground, just that the ground is not equal distance from each leg (thus creating a "high leg" on delta configs). While there is a higher voltage leg, phase to phase is still the same voltage. Delta does have a ground reference just fine though. I dont know what each leg is on a 600v system, but for 240v phase A and C to neutral or ground would be 120v, and phase B would be 208 volts.

                          I have wired VFDs on delta input power and they work just fine, all of our production room is run on a 240v delta transformer. The power is just taking it from the 3 phases so it really doesnt know whether it is delta or wye, so delta wont be the problem in this situation for the OP.



                          As for the power filter, not sure if it will work or not. It says it is meant for Wye, and the high leg on delta may cause a problem where it is constantly trying to suppress what it thinks is a spike every cycle of the power, which would be very bad.
                          Delta Power has at least 3 'flavors' that I know of:

                          1. Most 230v systems are as Mike describes, one winding is center tapped for 120 on each side of neutral, and the other two legs join to form a 'high leg'.
                          2. Open Delta is found in some older power systems, where there is no grounded reference on the transformer secondary, and floats. It was thought to be safer than having a solid ground reference, but has been out-lawed in most areas for safety.
                          3. Corner Ground is a fairly common solution to Open Delta, and is normally required to have a bonded neutral, so only 2 phases are broken through the disconnect.

                          We see all 3 in our area, sometimes more than one in the same facility!

                          My point is that with Open Delta, you never know what the voltage to ground actually is, since it depends more on capacitive coupling. The humidity and condition of the insulation makes a huge difference in this voltage. When the input filters on MOST drives are tasked with shunting noise and spikes to ground, they require that the nominal voltage to ground be below the rated input voltage. This isn't always the case without a solid ground reference. So, when it gets too high, the factory installed smoke leaks out

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                          • #14
                            I also feel like the Delta supply could be the problem. Not knowing what style of Delta (ungrounded/open or high leg, when there is a fault, noise, spike, etc, the GS2 Drive's input filters can't direct the fault to ground without seeing a tremendous voltage to ground, in turn, sacrificing themselves and possibly blowing the breaker up in the process.

                            I know the new GS4 Drives have a jumper you can remove the EMC filter from the equation. The other GS series drives do not. Every ABB drive I have used has a screw that can be removed for such a scenario. I have made it a point to only installing ABB drives, they seem to work for my application. My stuff is all 480V, so not sure how the 600V readings are affecting you on the upper end of most ratings.

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                            • #15
                              Guys, please understand what youíre talking about.
                              delta and star (or Y) are modes of connecting the electrical motor only. It happens inside the motor connection box by proper seating of some copper blades.

                              The Ac drive can not be connected delta or star. The Ac drive is simply connected to 3 phases and neutral. The scrambling of the three phases ( which one is R, S or T) is irrelevant for Ac drive. Check my previous message on how Ac drives work.

                              there are no favours of delta. There is no such thing as ungrounded delta. A delta connection is composed of three phases plus neutral. Please donít mess with things beyond your understanding

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