Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  1. stevenal

    Spain and Portugal power grid collapse

    NERC take on the blackout
  2. stevenal

    The floating star neutral to earth voltage in transformer.

    I confess I'm having a hard time imagining phasors that would lead to these values. Just the same I would connect a 2K ohm resistance from N-G and see if the N-G voltage drops to near zero. I understand 2K is what Fluke uses in the Auto-V LoZ setting.
  3. stevenal

    The floating star neutral to earth voltage in transformer.

    Or instead of using an antique voltage tester, you can use a modern device that has a low impedance input. Fluke calls these capacitive voltages "ghost voltages".
  4. stevenal

    Mexican navy tall ship slams into Brooklyn Bridge

    I was able to find a video showing how hydraulics are used to change propeller pitch. It seemed rather complex by itself, and it failed to mention how two hydraulic hoses are attached to a rotating shaft. How is this done and is it failure prone?
  5. stevenal

    Electrical power system protection - book

    Here are a few updated links to free downloads David mentioned in his FAQ: The Art &Science of Protective Relaying Network Protection & Automation Guide (NPAG) 2012
  6. stevenal

    Txf DGA sampling question

    https://www.sdmyers.com/knowledge-vault/sampling-part-3/ To the top they say. I suppose moisture could migrate into or out of the gas space prior to testing.
  7. stevenal

    Restaurant Booth Seating Live load

    The last wedding I attended had folks all jumping in unison on the dance floor.
  8. stevenal

    Spain and Portugal power grid collapse

    So what is "induced atmospheric vibration" and how does it cause loss of synchronism?
  9. stevenal

    Rogue Climatologists

    Not true. Some of the margin is made up by nice carbon free dispatchable hydro. Of course some wish to breach the dams to ensure your statement becomes true.
  10. stevenal

    120/240V 1P-3W, 100A Service to Very Remote Building

    Waross, The project I was involved with was residential and subject to the USA NEC. As I indicated, it was approved by the AHJ. The customer knew that not all electricians will work on the 7200 V portion and decided to proceed anyway. He did the trenching and cable laying himself, and found a...
  11. stevenal

    120/240V 1P-3W, 100A Service to Very Remote Building

    There should be no problem with the system proposed. I've seen problems using 120/240 winding with a neutral connection used as a step up transformer. The result is unbalanced current and voltage, and possible overloading. All balanced out with the neutral wire removed. Have you found a source...
  12. stevenal

    Internal Diesel Storage Tank dimensions

    The stationary diesel tanks I've seen have double walls in order to have built in secondary containment. Actual interior tank dimensions would be much smaller.
  13. stevenal

    Query on grounding of VT primary side

    To provide a reference.
  14. stevenal

    Transmission ground distance relaying with distribution underbuild

    Thanks. Not much fault variability once it got beyond the "pre-fault" stage. I tried some calculating in Sychrowave Event, zoomed in on the pre-fault.
  15. stevenal

    Transmission ground distance relaying with distribution underbuild

    I had the path wrong on G-H, it does share a path with F-G for part of it's length. As far as G-H coupling with F-H, would a parallel path 2000 ft away for 2.4 miles have an effect?
  16. stevenal

    10 VAC between line and ground when circuit breaker is off?

    https://dam-assets.fluke.com/s3fs-public/2105317_A_w.pdf?VersionId=ay9a7MLeqmnY7PfwYfAwHUEmUfd5yh_a
  17. stevenal

    Transmission ground distance relaying with distribution underbuild

    I can see there'd be some mutual coupling between F-G and F-H as they run down opposite sides of the same road as they exit F for several spans. G-H does not share a common path with the others, although the distribution underbuild may link them. I'll see what I can do to model the F-G and F-H...
  18. stevenal

    10 VAC between line and ground when circuit breaker is off?

    Gotta love those modern high impedance digital multimeters. Every little bit of capacitive or inductive coupling from other circuits is captured. 10 V is a small fraction of the normal 120 V to ground, so you have the right breaker. No adverse effects.
  19. stevenal

    Harmonics in the Neutral

    Triplen harmonics add in the neutral. It is common to upsize the neutral for non-linear loads.
  20. stevenal

    Transmission ground distance relaying with distribution underbuild

    I'm seeing nothing simultaneous, but a 17 A line to ground contact would not be picked up as a fault on distribution.

Part and Inventory Search

Back
Top