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  1. enverd

    VFD controlling an Air Handler Failures

    crshears, you got it, I absolutely don't work for ABB :-) I am an electrical engineer working for a consulting company and my designs go basically as far as complete specifications and construction documents showing power points of connection. My first response to the Construction Managers was...
  2. enverd

    VFD controlling an Air Handler Failures

    Thank you jraef. I am sorry for not having any better information and you are correct they are ABB drives and I am asking the same question, how would you know what the faults are. Looking past that, the obvious alarms/faults are "Motor Overtemp" and "Overcurrent" Does that indicate anything...
  3. enverd

    VFD controlling an Air Handler Failures

    Hello All, Recently a new Air Handler Unit was installed and it came with an 9 dedicated VFDs. After the start up there have been constant issues where the first two weekends we had electrical over-current alarm, the weekend after nothing happened and this past weekend the Unit shut itself...
  4. enverd

    Does anyone have a PDF copy of GB19517-2009 national safety technical code for electrical equipment

    need to review for a project in china. thanks in advance
  5. enverd

    Does anyone have a PDF copy of GB19517-2009 national safety technical code for electrical equipment

    Need to review it for a project in china. thanks in advance
  6. enverd

    Louisiana License

    If you are a registered engineer in one state, why would you need to take a separate PE exam in another state? I am registered in California and I went to NCEES website, then I went to the section that says; "Need to practice in more than one state?" (or something close to that), there you sign...
  7. enverd

    Motor with Gearbox vs. High Efficiency High speed motor

    Great stuff Mike, Thanks,
  8. enverd

    Severance or relocate

    I live on the west coast and it is expensive here. The Bay area is even more expensive. I am originally from Europe and have been in the US for about 15 years. Currently married w/ kids but no immediate family in the US, I mean none at all. The worst thing is not having someone around. If I...
  9. enverd

    Online Classes

    I took a couple of online classes and they turned out exactly what I thought they would be: It is not as efficient as being in the class. The instructors are there to give you a guideline rather than to teach you the actual (entire) material. You will however have access (email) to the...
  10. enverd

    Motor with Gearbox vs. High Efficiency High speed motor

    Thank you Lionel and Mike. Great points and like Lionel said these threads should be dwell-ed on to eliminate the confusion and any wrong information. Just to clear some confusion that I created. The VFD drives didn't change at all. Both drives are ABB ACH550 which used to feed old setups...
  11. enverd

    Motor with Gearbox vs. High Efficiency High speed motor

    Mike, That was the breakdown I needed, I knew 95% of all of what you said. As a matter of fact I was just explaining the V/Hz ratio and the variance between these two parameters to keep that Torque constant. Theoretically I did a lot of research in the past on the motors and not quite that...
  12. enverd

    Motor with Gearbox vs. High Efficiency High speed motor

    Mike, thanks for the graph. Dwelling on this a little more but in the meantime, are you saying that in this case we the VFD is varying the voltage and the frequency starting at 60Hz and 230V and ramps it up to 120Hz, 480V? Generally, for a typical motor the VFD would vary/control V/Hz ratio...
  13. enverd

    Motor with Gearbox vs. High Efficiency High speed motor

    Just when I thought all this makes sense, Mike comes along and kills my dream :-) Just kidding, thanks for the feedback and the breakdown. See attached picture that has side by side info, cut sheet of new motor (all I got for now) and the nameplate of old. New motor obviously is a 4 pole...
  14. enverd

    Motor with Gearbox vs. High Efficiency High speed motor

    Hi LionelHutz, The VFD ramps up the motor up to the required speed of above 4000RPM. It never functions at low speeds, less than 120Hz. So when you say 240V, 60Hz that is the ramping V/Hz ratio to bring it up required level. When you say: Taking it back to the grid connected ratings, the...
  15. enverd

    Motor with Gearbox vs. High Efficiency High speed motor

    Curiosity is taking over so I took a trip to visit this new motor. Actually we have two instances but only one of the new motors has been installed so that gave me the opportunity to see the old setup and the new one. The old setup is made up of 350HP, 2-pole, 460V, 3phase, 60Hz motor with max...
  16. enverd

    208v load vs 120v load

    Generally at higher voltage 208V or 480 and additional phases your load will go down because it is distributed between A-B or A-C or B-C or A-B-C etc.. vs running on one phase at 120V. The watts or energy consumed is dictated by the type of load and its specifications. So you really can't just...
  17. enverd

    Motor with Gearbox vs. High Efficiency High speed motor

    Thank you all for your feedback, no new information was provided so far but when it comes I'll submit an update.
  18. enverd

    Multiple electrical services one generator.

    You shouldn't have a problem at all. We did a couple of installations where we had a similar setup and on one occasion we had two services in the same building. The biggest item to look out for is to have one common grounding point because you need to eliminate potential differences in the...
  19. enverd

    Motor with Gearbox vs. High Efficiency High speed motor

    Hi Mike, Thanks for the feedback. Below information is coming from the manufacturer. This is not something I came up with. It is actually information coming from the cut sheet. The new motor is a 350HP, 480V, 3phase, Inverter Duty, 5500 RPM Max......Its base speed is 3550 This information is...
  20. enverd

    Motor with Gearbox vs. High Efficiency High speed motor

    Thanks jraef, The reason why this is full of holes is because I am working with insufficient information. Unfortunately, this project has been lingering around for years and the Process and Mechanical Engineers have decided back in the day to do, what they saw as, one for one replacement...

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