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Recent content by emoltzan

  1. emoltzan

    Three Phase Transformer Polarity

    Based on that, and from what we thought earlier it looks like a 60 deg phase shift when comparing both secondaries. I was attempting to do some phasor comparison with 60deg angle between two phasors with equivalent magnitude (480V)and still not coming up with the 280V we saw.
  2. emoltzan

    Three Phase Transformer Polarity

    I understood that much, I was more looking for a diagram/explanation of how the 277V was obtained.
  3. emoltzan

    Three Phase Transformer Polarity

    I have a question that came up the other day when we were putting tie breakers between 2 480V switchboards. We have a 2 5kV breakers each feeds a different 4160-480V Delta-Wye transformer. These transformers each feed a separate switchboard with breakers. We tied these switchboards together...
  4. emoltzan

    Different Horsepower, Same Load

    I'm not asking whether it's a pump or motor issue.
  5. emoltzan

    Different Horsepower, Same Load

    waross, I see you put up a ton of great comments/material. Are you open to direct PM? I would love to talk with you in the future as I am young in my career. Thanks
  6. emoltzan

    Different Horsepower, Same Load

    Both TEFC Drive the same type of pump Motors are independent of each other
  7. emoltzan

    Different Horsepower, Same Load

    Scenario: We have 2 motors, different horsepower, driving a vacuum pump that is loaded the same. -Motor #1 is a 3phase, 460V, 60hp motor -Motor #2 is a 3phase, 460V, 75hp motor Motor #1 runs at about 66 amps and then climbs to 80 amps and eventually to 100 amps then the overloads trip out...
  8. emoltzan

    VFD Load Reactor / Ferrite Core Placement

    We are currently working on solutions to reduce bearing currents in our motors, that lead to raceway fluting / EDM. With our VFDs we use load reactors and now are considering ferrite cores on the VFD load side. My main question is; after reading several references/recommendations I understand...
  9. emoltzan

    Generator Power/Torque Angle

    Hello, I am looking for some clarification on generator power/torque angle. I am asking for an explanation on how exactly kW output is increased/decreased. I am slightly confused as when you are synched to the grid how can you put out more/less power but still maintain constant 3600 RPM? I...
  10. emoltzan

    Transformer In rush current

    The reference I have states the following: Xfmrs <= 2500kVA have an inrush of 8xFLA @ 0.1s Xfmrs > 2500kVA have an inrush of 12xFLA @ 0.1s
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