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  • Users: jbartos
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  1. jbartos

    Coil Winding Efficiency

    Comment: The insulation layers somewhat protect conductors insulation during the coil winding process since there are tensions under which the conductor is being formed into a coil.
  2. jbartos

    Protecting equipment from lightning???

    Suggestions to Wittenborn (Aerospace) May 28, 2004 marked ///\\A guy I work with just read a book concerning computer hardware/software, and how to protect them from lightning. The author suggested that if you tie the cord in three knots (between the outlet and the computer) it will protect the...
  3. jbartos

    determining voltage drop for 1-phase lines

    Suggestion: The NFPA 70-2002 National Electrical Code does care about voltage drop more than the above posting suggest. Namely, the Article 647 includes: """(D) Voltage Drop. The voltage drop on any branch circuit shall not exceed 1.5 percent. The combined voltage drop of feeder and...
  4. jbartos

    Starting current for squirrel cage prime mover on a cent. pump

    Comment on electricpete (Electrical) Mar 18, 2004 marked ///\\ The pump will affect how long that starting current lasts. ///True.\\ The more torque the pump draws during startup, the longer it takes the unit to get up to speed and longer the starting current lasts. ///It depends. If the motor...
  5. jbartos

    The Use of Explosion Proofs Motors on Distortion Supplies

    Comment: This is essentially eng-tips Forum. Lengthy discussions do also appear; however, any practical usage often needs to be either proven, derived or referenced. This is the biggest strength of engineering and eng-tips.
  6. jbartos

    High Leg on Delta-Delta Transformer causing problems

    Suggestion to jjdad (Electrical) May 26, 2004 marked ///\\ What has me baffled, is the breaker that always trips is two breakers upstream from the transformer. The breaker feeding the transformer and the breaker feeding that power panel never trip. All of the three of these breakers are rated at...
  7. jbartos

    determining voltage drop for 1-phase lines

    Suggestion to the previous posting: Every footnote in NEC counts since it is the Electrical Safety Code.
  8. jbartos

    Synchronous motor question

    Suggestion to rmw (Mechanical) May 27, 2004 marked ///\\For you that are contributing to this thread, how does this discussion pertain to the 1-10 HP synchronous motors that I mentioned in the thread starter. Remember that it is a ME asking the question, so you have to try to couch your answers...
  9. jbartos

    determining voltage drop for 1-phase lines

    Suggestion: Reference: NFPA 70-2002 National Electrical Code Article 210.19(A)(1)(FPN No. 4): FPN No. 4: Conductors for branch circuits as defined in Article 100, sized to prevent a voltage drop exceeding 3 percent at the farthest outlet of power, heating, and lighting loads, or combinations of...
  10. jbartos

    determining voltage drop for 1-phase lines

    Suggestion to peebee (Electrical) May 27, 2004 marked ///\\Note that ASHRAE-90.1 (which is well on its way to being adopted here and there and everywhere across the US as we speak) has tighter requirements for voltage drop than NEC: Feeders: 2% at full connected load Branches: 3% at full...
  11. jbartos

    servo motor voltage

    Suggestion: NEMA standard ratings of industrial dc motors for 240V and 500/550VDC supply voltages are given in Tables 10-4 and 10-5 in NEMA Std MG-1
  12. jbartos

    Starting current for squirrel cage prime mover on a cent. pump

    Comment on electricpete (Electrical) Mar 18, 2004 marked ///\\Regardless of what you do to the pump, you will initially have a starting current ~5 - 7 times full load amps (excluding initial exponentially-decaying component). ///Yes, unless there is a different motor applied with the lower NEMA...
  13. jbartos

    The Use of Explosion Proofs Motors on Distortion Supplies

    Comment: The explosion proof enclosures have been around for more than 50 decades. There are fairly mastered technologically. E.g., chemical industry, petrochemical industry, etc. have been using explosion proof motors for long time and worked on their improvements together with industry...
  14. jbartos

    Cable Gland Earthing

    Suggestion: Visit http://www.ehawke.com/certs.htm http://www.indiamart.com/meghna http://catalogs.indiamart.com/manufacturers/electric-wires-cables.html http://www.cableglandsindia.8m.net/accessories.htm http://www.directindustry.com/ and search for cable gland literature. etc. for more info on...
  15. jbartos

    Failure of 11kV Cable

    Suggestion: Reference: Dr. Professor Dean C.L. Wadhwa "Electrical Power System," John Wiley & Sons, 1991, Chapter 6 Corona, pages 135-149. Method of Reducing Corona (Loss) 1. Large diameter conductors, 2. Hollow conductors, and 3. Bundled conductors.
  16. jbartos

    Voltage Transients and Fuel Pipelines

    Suggestion: Be prepared to apply a lot of copper and air terminals, if the pipeline is long. Incidentally, how long is the pipeline?
  17. jbartos

    Influence of impedance voltage

    Suggestion: zelvica (Electrical) May 11, 2004 marked ///\\a group of 70 transformers, minimal value of uk=3.5% maximal value of uk=5.9% average of the group is 4.9% relative difference between max and min is about 68% How would affect the results (load flow, short circ. calc.) if we approximate...
  18. jbartos

    Transformer inrush current simulation

    Suggestion: Visit http://www.ipst.org/TechPapers/2001/IPST01Paper012.pdf http://www.mathworks.com etc. for more info
  19. jbartos

    LIGHTNING PROTECTION

    Comment: The galvanic connection of the transmitter/receiver to the telecommunication tower needs to be protected against lightning. The following article recommends unplugging antennas: http://www.sundayobserver.lk/2003/05/18/new25.html however, if the transmitter is supposed to be in service...
  20. jbartos

    AARRGHH!!!

    Suggestion to skiier (Electrical) May 26, 2004 marked ///\\Jbartos. I don't understand your reply? "equal to or greater than..." tells me I can use ampacity "equal to.." and I don't have use use an ampacity "greater than...". ///Yes, if the application results in such case.\\Is a conductor with...

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