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 MintJulep 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: *

  • Users: Humble2000
  • Content: Threads
  • Order by date
  1. Humble2000

    Schweitzer Relay- 51a & 51b

    Under relay settings for 50 , I see two settings 50a,50b 50Na and 50Nb, what are these parameters represent?
  2. Humble2000

    Transformer LG

    If the main secondary breaker has ground fault protection, do we still have to protect the transformer shifted curve on delta-solidly grounded wye transformer against phase-ground faults which is shifted to the left?
  3. Humble2000

    Three phase from single phase

    I am looking for a device to generate three phase signal from a single phase transformer. I appreciate any feedback on this.
  4. Humble2000

    Ac Milliamp current generator

    Folks, Does anybody know wehre I can get a device to generate variable milliamp current (AC) between 100-600mamp I am not looking for a fancy device. Just a simple mamp ac current generator. I know I can use voltage and resistor ;however I need it to be controlled via a HMI or PLC.
  5. Humble2000

    Unbalance Current Detection

    I am looking for a meter to detect unbalanced current. This means if one phase current is more than 10% in difference with other two ,the unit initiates a trip. I also have one set of CT’s which are source for Crompton Ammeters. There is diagram for connecting two meters in series, is this going...
  6. Humble2000

    AC Motor

    If I run an AC motor without a load, and the voltage drops current drops too.in what situation if the voltage drops ,current goes up. I guess when I have a load on the shaft and motor tries to compensate for that load right? Please refer me to articles on this subject. Thanks
  7. Humble2000

    How clos is inrush point to the curve

    Attached is a result of coordination study of a fault fiter fuse( S&C ) and low voltage ckb. What margine need to exist between the inrush point and the fuse curve to safely order the fuses?
  8. Humble2000

    NGR-Arc Flash

    Can NGR reduces arc flash on the secondary side of delta-wye grounded transformer?
  9. Humble2000

    Transformer Impedance-Inrush

    Its a liquid filed 3000KVA/4000KVA, 13.8/600 delta wye, z=10%. Is inrush current still 12 time the FLA for .1 sec?
  10. Humble2000

    Transformer seconday side Breaker

    a 750KVA ANN transformer secondary side breaker is ordered with a 1000AMp LTP and fixed LTD . This is 1.4 times more than Tx FLA at 600V. Breaker is rated for 100% rated name plate operation. Two issues is first the primary S&C fuse at 25KV does not coordinate with a 25 AMp fuse ( they touch at...
  11. Humble2000

    Standard ARc-FLash Hazard Lable Size

    Assuming no size limitation, what is the standard (specified) size of these labels (eg 4 x 6 inches)? Is there a code or regulation to print these labels on a specific size?
  12. Humble2000

    Loss of Voltage in Delta System

    Quote" In a delta system, the loss of one phase results in sensor readings with magnitudes slightly more than 1/2 of normal phase-to-phase voltage. Simultanious loss of two phases is not detectable as a phase imbalance condition. Does this line make sense?
  13. Humble2000

    Multiples of Tap Value Current

    Hi , I have a CO-11 Relay which under CT Ratio shows Value=160 and under Remarks I have 3 X 3200/(2400)/2000/(1600)/1000:5 A The Instantanious PU is 4800. I am confused how to project this on TCC curve and also what are the meanings of those CT ratios? where did they get 160 from? I appreciate...
  14. Humble2000

    TCC Curves

    I am looking for TCC curve for Westinghouse breaker type CO-11.and ASEA breaker Type RXIL24-111DM .Does anyone know where I can get them from. Thank you
  15. Humble2000

    Single-Phase, Three Wire System

    If a single phase transformer primary is connected to L-L voltage, only one half of the three-phase short circuit MVA( GE SC calculation Manual, Page 33).Does anybody have reference to this calculation? Thank you,
  16. Humble2000

    Small Application Software

    Dear Friends, Could somebody give me some direction on how to solve equations in attached document? If possible I’ll like to create small user-friendly application software which could show the results when inputs are entered. I know that this could probably e done with “C’ ,but It’s been long...
  17. Humble2000

    Resignation

    I had a bad experince in my previous job. I gave my resignation letter to the boss. 1 week before quit date. I though this will give them enough time to wrap up the projects and other stuff. BAD IDEA..... They started being nasty.. at the end of the day they threted me like a criminal, checking...
  18. Humble2000

    Ground Fault protection

    In a 3 wire grounded system, if the main breaker has a ground fault function, the CT's common will need to be connected to ground terminal of the relay. I know that in this case the sum of three currents will pass to ground and create a signal to activate the relay. How the setting and...
  19. Humble2000

    Detect Ground Fault

    How can we detect the ground fault location in HRG or floating ground sytem. XFMR is Delta -Wye XO is not grounded or HRG is installed. Thanks
  20. Humble2000

    LA Megger Test

    Is meggering a lightning arrestor really a good test to show if the LA is good or not? I usually test the 8KV and above Las at 5Kv and if I am reading more than 1000MG then I assume its good reading; however I am told that intermediate La’s are resetting themselves and meggering a LA is not a...

Part and Inventory Search

Back
Top