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 TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Recent content by xnuke

  1. xnuke

    REMOTE START / STOP FOR LVR MOTOR CONTROLLER FIRE PUMP

    If you had two three-way switches and one four-way switch, you could wire the three switches the way you would wire a lighting circuit controlled from three places. They are available as products suitable for industrial use. xnuke "Live and act within the limit of your knowledge and keep...
  2. xnuke

    Clearance Difference between 12.47 kV and 13.8kV Overhead Line

    I agree with jghrist - those dimensions look fine for 13.8 kV (see NESC Section 235 for reference). However, the military overhead line construction specification has pretty good pole details similar to the detail you posted. See here, and look under Related Materials for "Pole Details." xnuke...
  3. xnuke

    Synchronizing solar,wind, and grid

    Distributed energy inverters and battery power converters provide the sync check internally - they sense the AC voltage, frequency, and phase on both sides of their AC contactor and they modulate their output to match the line side before closing. That's why they won't return to operation in...
  4. xnuke

    Synchronizing solar,wind, and grid

    Bold text are my changes to your text. IEEE 2030.7 calls this the grid-connected steady state. I encourage you to think of solar and wind acting as negative load rather than generation sources since we can't cause their output to go up on command, only down. The battery should be used for...
  5. xnuke

    Synchronizing solar,wind, and grid

    You're describing an islanding microgrid. When grid connected, the distributed energy resources, i.e., PV, wind, battery energy storage system (BESS) will operate in parallel with the grid. When the grid goes down, a point of interconnection disconnecting device should open to disconnect the...
  6. xnuke

    Need Advice - Should I get a PhD?

    I'm a former professor at a teaching polytechnic with a MS in engineering and fifteen years of engineering experience before I started my faculty position, and I agree with every point made by Enable. I took a 25% pay cut to take the teaching position, but I did it because I knew I loved...
  7. xnuke

    Multiple PID Loops (PLC)

    Sounds like you might want a ratio control loop using measured gas concentration downstream of the mixing point to control the air added with the gas as an uncontrolled variable to get the right mixture. There are multiple ways to do this, e.g., measure gas flow and ratio the measured air flow...
  8. xnuke

    Delta-Delta vs Wye-Delta Step Up

    Another vote for delta on the LV side, as it sounds like you have a HRG system at 480 V. You don't want to put in a grounded wye on that side of the transformer with a HRG in the system. I also recommend avoiding both the terms "primary" and "input side" as I've been working a lot with...
  9. xnuke

    Why there is a negative current flowing into solar panels

    Yes, that can happen. Sounds like you may need blocking diodes to prevent reverse current flow. xnuke "Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged. Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
  10. xnuke

    Feedforward: why does feedBACK reduce itself?

    I agree that since feedforward is open-loop, it cannot provide perfect correction, but saying feedback alone works better is not typically correct. Your expectation that feedback does most of the work is in fact backwards in most systems with both feedforward and feedback controllers. As to...
  11. xnuke

    What is typical switchgear DC control power voltage in Germany?

    Thanks, seanleed. xnuke "Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged. Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
  12. xnuke

    What is typical switchgear DC control power voltage in Germany?

    I realize this question is somewhat customer-specific, but what are people seeing a lot of customers using? 24 V DC? 48 V DC? 125 V DC? 250 V DC? Other? xnuke "Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged. Please...
  13. xnuke

    A very simple PLC application & zero budget for hardware ??

    Check out AutomationDirect components (I am not affiliated). They have options that are less expensive. xnuke "Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged. Please see FAQ731-376 for tips on how to make the best use...
  14. xnuke

    690VAC distribution in USA

    Not true, the cutoff is 1000 V, and has been for several code cycles now. I agree with the others, no one I know uses 690 V, they use 600 V because ANSI standard voltages are integer multiples of 120. That's why the cutoff in the NEC used to be 600 V. My understanding is that it was increased...
  15. xnuke

    Resistivity of carbon steel 7-wire prestressing strand

    You don't need to buy a ductor, you can rent one or find a local company that does electrical testing that owns one and pay them to test your wire. I think that either of those solutions is better and safer than trying to make your own. It will be calibrated, able to deal with drift, and UL...
See more

Part and Inventory Search

Back
Top