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  1. Freshsurfer

    Use of over-sized VFD

    Hi! I'm working on a application of a VFD for a motor of 40hp @ 440Vac. The client has a 211 amper capacity VFD. Can I use it for a 40hp (50A) 440Vac motor? Is probably to have some Harmonics issues due that high of over-size?
  2. Freshsurfer

    Overvoltage during a VFD start

    Thanks @jraef, ABB guys are working on that. My concern is about the other electrical equipment plugged at the same 480Vac bus that would suffer this overvoltage. They said that could be a grounding issue and they will check if the common point of the secondary part of the transformer (neutral)...
  3. Freshsurfer

    Overvoltage during a VFD start

    Thanks @jraef! Yes we have some non-AFE drives on the same 480Vac bus. They are tripping due overvoltage when the ACS880-37 is running, also the main transformer is vibrating. All this effect could decrease when the rest of the equipment begin to operate? There are a large number of inductive...
  4. Freshsurfer

    Overvoltage during a VFD start

    Hi @LionelHutz, the equipment where the VFD is applied is a conveyor totally flat non regenerative. At the same area we have a MV drive (ACS2000) with some fans in 480Vac that are feed by the same 480Vac bus, they have burned due this overvoltage. Also we have a crane that trips by overvoltage...
  5. Freshsurfer

    Overvoltage during a VFD start

    HI @waross, yes it is an 460Vac 50Hz. The site is a copper plant in Chile. Hi @jraef, the VFD is an active front end (ACS880-37). Based on your explanation there is no way that the sinusoidal output filter could being causing this overvoltage, right? I'm in Brazil bringing support to our guys...
  6. Freshsurfer

    Overvoltage during a VFD start

    Hi @davidbeach, I don't have this information yet, but it burns some fans in other equipment below the same MCC, I'm expecting that this could be higher than 30% above the nominal voltage.
  7. Freshsurfer

    Overvoltage during a VFD start

    Hi, thanks for your comments! Here more details: Motor voltage: 460Vac 50hz MCC voltage: 480Vac After discuss with our supervisor, we have more relevant information: the length of the cable from the VFD to the motor is about 580 meters. Due that the drive have a sinusoidal filter in order to...
  8. Freshsurfer

    Overvoltage during a VFD start

    Hi, We're doing a commissioning procedure over a 150kW (460Vac) conveyor. This motor have a VFD. During the start (without load)we note an overvoltage on the 460Vac MCC that feeds the VFD. It could be a problem on the transformer? or some kind of harmonics distortion that is causing this effect?
  9. Freshsurfer

    THDi Current Harmonic distortion could cause over voltage?

    Is a regular conveyor with a 150% max overload. And yes, its a new installation and we are on commissioning, I believe that maybe it was a grid issue, but our client is associating this concern to the high level of harmonics due the drive pre-charge. My argumentation for is that a high level of...
  10. Freshsurfer

    THDi Current Harmonic distortion could cause over voltage?

    Sorry, THDi = is the amount in % of the current harmonics generated by the drive. We are assuming that this condition is happening during the pre-charge process before the motor start to run.
  11. Freshsurfer

    THDi Current Harmonic distortion could cause over voltage?

    Is just during the starting, we suspect that is during the VFD precharge process, before the motor start to move. But is possible that a THDi can cause an over voltage?
  12. Freshsurfer

    THDi Current Harmonic distortion could cause over voltage?

    Thanks all for your reply! @RedSnake, I'm totally agree with you if we are talking about a high moment of inertia load. But in this case is a conveyor without inclination, It's totally flat and working without material cause its on commissioning. So, maybe there was another kind of...
  13. Freshsurfer

    THDi Current Harmonic distortion could cause over voltage?

    Hi, after some overvoltages trips on a VFD our client did some measurements on the LV MCC bar and found a high level of current harmonic distortion. It could cause the overvoltage on this VFD and other components? Note: No voltage harmonic distortion was found. Thanks!
  14. Freshsurfer

    AVEVA Electrical

    Hi, I`m looking for user experience on AVEVA Electrical, I`m very interested to purchase it, but I didn`t found enough information about its capabilities, does somebody already use it?
  15. Freshsurfer

    Engineering design software

    Hi, I`m looking to find some new software to help on the electrical dimensions issues that are the main concerns during a tight schedule projects. On a ideal project, electric design starts after the main mechanical project detailing is done, I mean, all the motors are defined, also the...
  16. Freshsurfer

    Transformer Impedance definition

    Hi, I`m working on a 4.16/0.48kV 500kVA transformer specification. Who defines the impedance for it? exist an IEC standard for this?
  17. Freshsurfer

    Transformer BIL vs Altitude

    How can I select a right surge arrester to protect the transformer against a 75kV impulse on 4.16kV nominal voltage system?
  18. Freshsurfer

    Transformer BIL vs Altitude

    Yes HamburgerHelper, the distances between the terminal connections were derated. Now I´m with another understanding about the impulse test to verify the BIL design value. Why we perform the impulse test between each phase and ground and not between phases? Since an impulse test is by example...
  19. Freshsurfer

    Transformer BIL vs Altitude

    Thanks for your clarifications, there is another issue, is possible to attend a required BIL by installing a surge arrester?, we have a transformer with 60kV of BIL on a system where a 75kV of BIL is required?
  20. Freshsurfer

    Transformer BIL vs Altitude

    In order to avoid the need to derate the BIL for the connection terminals of a transformer is possible to encapsulate its connections?

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