Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

Search results for query: *

  1. JatTiw

    Motor Problem

    Application is for centrifuge pump in refinery. Electricpete & Edison123 thanks your support & shedding light on the issue. Best Regards
  2. JatTiw

    Motor Problem

    From PdMA test, the %age imbalance in resistance & inductance are 0.78% & 3.65%.......Looks like OK to me. Also please help me under stand why high efficiency motors will have high inrush as compared to normal motor. My thoughts were other way around.
  3. JatTiw

    Motor Problem

    As per manufacturer, LRA-1085. Instantaneous trip at breaker is already set to maximum, cannot go above what code allows.
  4. JatTiw

    Motor Problem

    I have Siemens make 150hp (164FLA), 460V motor (IEEE-841, premium efficiency) is causing main HMCP to trip on start-up. PdMA results shows all OK (PI-10; DDA-1.9; Average Phase resistance & inductance 0.0635ohm, 2.008mH) Inst. Breaker set at 13*FLA. No problem with cable or starter. Is motor...
  5. JatTiw

    Sparking brushes of Synchronous Motors

    Like I mentioned in 1st thread, Only one machine has the problem, Other work fine.
  6. JatTiw

    Sparking brushes of Synchronous Motors

    No mechanical/maintenance type issues. New brushes/slip-rings/holders installed 3-4 weeks back. Enclosed & instrument air for cooling. Each time set of brushes on ‘-ve’ terminal develop spark.
  7. JatTiw

    Sparking brushes of Synchronous Motors

    I have two identical 4000hp Synchronous Motors operating reciprocating compressors. The ‘–ve’ terminal brushes on one machine tend to develop spark. The excitation control system (GE-Stat-x-ator) has almost the same volts/amps/pf for each machine, as the loading is identical. Need help to find...
  8. JatTiw

    Nuisance Tripping on Ground Fault

    All these feeders has Delta/Wye transformers (with low resistance grounding) connected to it and has no capacitor banks, non-linear loads (ASDs etc) or surge arrestors.
  9. JatTiw

    Nuisance Tripping on Ground Fault

    I need help to solve a puzzle where some of the feeder breakers for healthy circuit were tripped cause of fault in one feeder, connected to same bus. Problem started with failing of few capacitors of capacitor bank and caused the tripping of capacitor bank feeder breaker on 3-phase instantaneous...
  10. JatTiw

    Transformer Bushing

    I need help to identify the difference between distribution class and power class bushing for power transformer Thanks
  11. JatTiw

    15kV Cable

    Hi jghrist, HL rating is CSA designation for cables installed in electrically hazardous location (Class-1 Div/Zone 1 etc) & FT is fire test rating for cable comment,
  12. JatTiw

    15kV Cable

    Is there any problem for getting HL & FT rating for un-armoured cables also? Cause cable I am specifying un-armoured cables.
  13. JatTiw

    15kV Cable

    Thanks mpparent, do you have any contact info at Okonite
  14. JatTiw

    15kV Cable

    Hi Every body I am looking for Three (3) copper conductor, 350 MCM, 15 kV, 133% insulation level with semi-conducting thermosetting layer as well as metallic tape, cable with EPR (Ethylene Propylene Rubber) insulation, shielded and PVC jacketed, HL rating & flame test-rating FT-4, CSA approved...
  15. JatTiw

    API Standards for less than 250hp motors

    Hi Every-body, The API 541 deals with motors above 250hp in Petroleum & chemical industries. The question I have is which API or any other standard deals with motors below 250 hp in Petroleum & chemical industries.
  16. JatTiw

    Voltage Drop for Single Phase system

    HI, For single-phase system (Phase & neutral), the load is at ‘X’ distance form the source and to calculate the voltage drop in the cable, shall I use 2X distance (X-for phase wire + X-for neutral wire) or just X-distance?
  17. JatTiw

    Transformer Data Sheet

    Hi, Any body knows from where I can get transformer data-sheets (in Table format)?
  18. JatTiw

    Why utilities use Wye-Wye Conneted transformer??

    Hi Brupp Can you verify the publication number GET-3388B is correct? I am in contact with GE personals & they could not find this publication number. Regards
  19. JatTiw

    Why utilities use Wye-Wye Conneted transformer??

    Hello, I had two questions 1) Why utilities are using Y-Y connected transformer for power distribution? The only advantage I see is the cost (less insulation). Are there any other advantage/ disadvantage of using this type of transformer? 2) What are the disadvantages if both the star points...
  20. JatTiw

    VFD and cable

    Hi Buzzp, I am quite sure with the cable length for your application you will have the problem of cable charging current due to harmonices (result of PWM) in the system. A suggestion , Think about installing some active filter system
Back
Top