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!

Search results for query: *

  1. Morquea

    Changes to the definition of arc flash boundary in upcoming NFPA 70E

    Maybe I overeact there or maybe I was anticipated overeaction from my trainees when I would have to debunk the "second degree burn" case. Even if NFPE 70E or the canadian equivalent CSA Z462 are not legaly binding, we have a criminal law that my clients have to comply too and showing that they...
  2. Morquea

    Changes to the definition of arc flash boundary in upcoming NFPA 70E

    I'm concerned since as you told, they making changes so that the criteria is not based anymore on second degree burn threshold but on an incident energy level which we believed was the threshold. Being a trainer on arc-flash matters, I always explained what represent the 1.2 cal/cm². So to...
  3. Morquea

    Low-voltage Cable Insulation Level Insulation - Follow-up

    Searching for reference about insulation coordination, I consult thread238-232606 from 2008 and though I should comment about what I find. Background First, I was questioning myself if a ACWU90 600V cable was suitable for a 600V application (Québec, Canada) considering that, by common practice...
  4. Morquea

    Cable connectors : can I grind them?

    Hi I have a number of feedthrough connectors TCF125-128AL for mono DLO 535 cable. The diameter of one end is too small. It's cause of varying OD diameter of the cable manufacturers. Southwire would have fit but not Carol. My men proposed to grind the opening end for 3/32 inch width. I was...
  5. Morquea

    Fault Current Limiter application

    Hello I'm looking for reference and opinion about Fault current limiter. Question Is there any papers or reference that allow to calculate, to compute, to quantify peak short-circuit reduced by a current limiter on all the load side assemblies? Context : Arc-Flash, short-circuit and...
  6. Morquea

    Current Limiting Fuse recommendation for Arc Flash reduction

    I give a star to david too. Basics are the key. Understand, Simmi, that a transfomer is an application of electromagnetism theory. To understand the why is there an inrush current, you must understand the magnetic relation between the windings and the magnetic core of a transformer. I agree...
  7. Morquea

    Arctic Grounding Systems

    Thanks for the acronym. The project is for a mining complex. They act as community, utility and previous module design served as pre-approved philosphy that we adapted to this projet. Past history shows no use of filler to improved conductivity for their current installation. I would ask about...
  8. Morquea

    Arctic Grounding Systems

    A ground rod provider suggest a fill to enhanced conductivity between rods and soil. Though, the provider didn't know about the arctic condition of the project. But it might be more than just structural design consideration but also an environnemental consideration since environmentale...
  9. Morquea

    Arctic Grounding Systems

    I'm actually designing a grounding systems for arctic climate. This thread is a follow up of an older thread thread238-196015 as to be a sample application. 1.0 Definition Artic : Regions where the soil is compose of permafrost. It includes Alaska, Northern Canada, Northen Scandinavia...
  10. Morquea

    Transformer Sizing

    My usual rule of thumb is this : Xmer KVA = 4(kVA/HP) * Pmotor(HP) For your 100A motor (assuming it's a 575V), that rule would size a 400kVA. I seldomly used that rule. I prefer do the following calculation : 1 - Evaluated the Locked Rotor Ampere - Usually a percentage of the FLA typicaly...
  11. Morquea

    Power System Study Report Format

    3.Executive Summary I put an executive summary section after defining the scope of project. It's a summary of the results and recommandations written without the too much specific technical vocabulary. It's intended to the client. I prefer it at the report's first pages than at the end. So...
  12. Morquea

    Working 40 hrs/week....somewhat....

    I'm a consultant firm member. My typical week, as describe in the employees manual, is 37.5 hours a weeks flexi with reccommended working hours from 8:00 to 16:30 with an hour lunch. I also have an overtime pay rate for excess hour over 40 a weeks (it's by province laws). I have the option to...
  13. Morquea

    Current's direction on relay for generator

    Lastest feedback on the project They decide to install a SEPAM-1000+. They won't dismantle the currently installed LGPG111 since there is room to install the new equipment. So they will just disconnect it and reconnect the CTs to the SEPAM. Thank you Slava for the continuous assistance you...
  14. Morquea

    Current's direction on relay for generator

    Hello Slava Thank you very much for your help. I'm confident now that we will be able to make our recommandation about the option of using the existing LGPG111 in regards to the option. The second option is to replace the LGPG111 by a relay with only 25-27-50-51-50GS-51GS (KCGU-140). Such...
  15. Morquea

    Current's direction on relay for generator

    ...it wouldn't be necessary to use those functions. I mentionned this cause we thought of suggesting to connect the 4160V side where only a KCGU* would protect the feeder. I was to discarded those functions thinking the weren't necessary. However, I think it would be nice to keep them if...
  16. Morquea

    Current's direction on relay for generator

    Answers to new questions : 1. No, there is no connection to utilities. The context is a remote mining site, where tundra is the kind of vegetation. There are 13 generator including the fives shown in the scheme. Seven of them are supposely dedicated for back-up supply. 2. Yes. When the PW1...
  17. Morquea

    Current's direction on relay for generator

    Thank you I attached a scheme of the connection between the two powerhouse. The relay in question will protect a transformer on the 4160V side. The winding are Delta on 600V and WYE (without ground) on 4160V. The 4160V bus bar is at the main power house and is tie with an other bus containing a...
  18. Morquea

    Current's direction on relay for generator

    I would like to find documentation about how the current direction could affect the proper fonctionning of a protective relay. We are connecting a 600V power house (PW1) to a 4160V power house (PW2) throught a step-up transformer. The grid configuration can allow to feed PW2 with PW1 and vice...
  19. Morquea

    High voltage regulators

    The distance between the distribution sustations and the mining site is 75 km. The fault level at the end of the line would be 250MVA @ 120kV and 115MVA @ 69kV. They allowed a 3% maximum voltages sags from motor starting. So, 500MW is about the largest motor power allowed @ 69kV. But...
  20. Morquea

    High voltage regulators

    Hi Question : Does a volatage regulator for 69kV line can could be used for a 120kV and vice versa? Does a auto-regulator on a line supplying 10MW would be affected and/or need to be change if we rise to 20MW. Link about high-voltage regulators would be appreciated. Project : Mining site...

Part and Inventory Search

Back
Top