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: *

  1. melspuds

    DC Shunt Motor Question

    Bill, I forgot about that way to calculate the impedance. Thank you! Dave
  2. melspuds

    Three-phase power supply US?

    480V wye or delta systems are the most common Low Voltage in industrial settings. 208V or 240V systems are mostly light industrial loads. 208V systems are normally used in offices, schools, ect. NOTE: Motor nameplate voltage is listed as 230V nominal for 240V systems. And 460V nominal is listed...
  3. melspuds

    HIGHER SERVICE FACTOR OF A MOTOR

    virata, You might have to change the overloads if the motor is working in overload conditions. Dave
  4. melspuds

    DC Shunt Motor Question

    podobing, Check the arc suppression of the arc chute for the contactor. If in doesn't an arc chute then that is your problem. The arc vaporizes the tips (contacts) and after "n" amount of breaking the load operations the tips will be worn to not able to work correctly. Also misalignment of the...
  5. melspuds

    Earthing of cable tray body

    When I design a cable tray system, I always use a grounded bare copper cable EGC (sized for the largest oc device). Mounted by cable tray grd support clamps on the bottom side flanges (either inside or outside). This is to allow for the joint splice plates to be able to move for expansion and...
  6. melspuds

    Ground Fault Interupter on 3 wire 480 system?

    1Millwright, Is this your first hot strip mill? I spent 35+ years working for 2 steel mill companies as an EE, with a total of 11 hot rolling mills, plus EMS melt shop, and finishing mills. You my have a 3 wire delta system with a small zig-zag transformer to develop a neutral point. The neutral...
  7. melspuds

    Need advice on how to make myself a "more valuable" employee.

    I don't know your location in the USA, but I bet you that Bechtel has jobs within 250 miles of you. They design, built anything, anywhere. The old saying is "if you want something built and have the money, Bechtel will built it". A few years ago Bechtel had most likely built 75% of all Power...
  8. melspuds

    Need advice on how to make myself a "more valuable" employee.

    THRILLHO, Do you have any electrical work experience? I started as an electrician, at the age of 16 in the summers and I put myself through college as electrician. In fact I made more money as an union journeymen electrician, than a EE for about 3 years in 1960's. What about a maintenance...
  9. melspuds

    Coils on power lines

    I read the question wrong, or what I wanted it to read.[ponder] MY MISTAKE What I stated is true, but for coils at every other pole or tower for the expansion/contraction. On long spans required vibration dampers. The owners of the lines with the coils would keep an eye on them for about 2...
  10. melspuds

    Coils on power lines

    Paul In the very early 1970's I worked for an large electrical contractor in central WI. He had several line construction crews and did a lot of work in U.P., N. WI., and iron mines in MN. When I was first reading of the spec's for on a lot of the jobs that could only be done in the winter...
  11. melspuds

    Can being in the same room as 13.6KV damage electronics?

    rmore Is the new 13.8kV feeder incoming out of the room anywhere near your 480V controllers outputs outside of the room. Since it's a new install, the cable(s) shield maybe damaged. An old lineman trick is to take a portable AM radio an follow the new 13.8kV feeder incoming from the room to is...
  12. melspuds

    Purge Panels

    Need more info. Is the purge system used for keeping vapor out of the enclosure you only need an inlet with a pressure regulator. If purge system is for vapor control and enclosure cooling most likely need inlet and outlet lines. I never seen purge systems on the top of the enclosure, mostly on...
  13. melspuds

    33/11 kv substation

    I have no idea where the install is. I do not believe that the cables have a metal sheath because of the tight 90o bends. Dave
  14. melspuds

    Leaking Switchgear Roof Repair

    I had the same problem. I was told not to spend any money on double ended 2400vAC 1600Amp switchgear, that was a 1930 vintage. Finally water entered into the swgr starting a fire on an inline CT. A temporary fix was pain ordinary roofing tar and made small hip roof out of plywood and covered...
  15. melspuds

    33/11 kv substation

    I still believe that they are cables, maybe some is painted. If it is conduit, it would be impossible to pull wire. Also most of the "cables" have a very tight (small) radius 90o which is impossible for conduit. After looking at the bottom photo, top right that maybe conduit using some type of...
  16. melspuds

    Emergency light

    Better check with the building, and other codes. It is normal practice to leave the emergency lighting circuits also on. Hopes this helps Dave
  17. melspuds

    ABB AMVAC in California and how do you do the control design

    All most all power switching breakers are DC. All substations use DC via batteries for switching and protective relays. In nearly 45 years I have seen one failed DC system. That was 48vdc system in a very small substation and batteries where bone dry also a small tree was growing in a breaker...
  18. melspuds

    33/11 kv substation

    That is not conduit runs, it is all cables. Please read above posts. Dave
  19. melspuds

    Parallel conductors feeding a three phase motor

    As Bill stated first check with AHJ. The only NEC problem that I see is changing wire size without OCP at the junction of 500kcm Al to 350kcm Cu. The amperage is about the same, but the difference in the cable size. I would think best thing to do, use 500kcm Cu instead of the 350kcm Cu. That...
  20. melspuds

    Square D Power-Zone Switch Assembly

    I believe that 5kV & 15kV load break switches are the seem switch but the fuses are, of course different. Square D calls that switch HVL (high voltage load). I do not have the Sq D Digest with me now, but I remember that bays are about 3'+ wide. Hope this helps and good luck, Dave

Part and Inventory Search

Back
Top