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Recent content by lansford

  1. lansford

    Transferred GPR to underground mine

    Lets say the main substation feeds a variety of stationary equipment. If so the Low side grouding of that substation can be solidly, ungrounded or resistance grouding. And you have a neutral run from that substation to the isolation substation or you do not have the neutral run. The isolation...
  2. lansford

    Design Engineering Training/Reference Material

    Find a local A/E firm who needs some incidental help at times. Then you can eventually become a "Professional Moonlighter" Jim
  3. lansford

    ANSI Code: Non-regenerative vs Regenerative VFD anyone got experience with this?

    In the world of surface mining equipment, specifically large electric draglines and power shovels, the older units were MG set (motor generator) powered. And you could observe on the utility source bus, the voltage fluctuation due to the load swings as the dragline went through its motions. A...
  4. lansford

    Expertise vs. Experience

    In my experience engineering firms will not turn away a job even if they do not have experience in that area. For example, firms that have no medium voltage experience, will not turn away a substation job. If they can't or more often won't get someone who has the expertise, they will wing it...
  5. lansford

    MV/HV underground Cable abandonement practice

    I think it boils down to this. Low quality contractors and plants with poor configuration management will leave the cables in place. Of course, direct buried needs additional consideration. Jim
  6. lansford

    cable fault locating in mines

    Sorry...Correction MSHA research group not OSHA Jim
  7. lansford

    cable fault locating in mines

    In stripping (open pit) and UG ore mines the energy release from a thumper does not matter and a good deal of energy is needed to find a cable fault in MV cables with resistance grounded systems. In coal mines with the potential for methane gas it could be an issue but I don't believe that I saw...
  8. lansford

    New Jersey seals on engineering reports

    I am registered in NJ and I just print my name and NJ License # at the end of my report. PERIOD Jim
  9. lansford

    Is there an "official" way that required engineering staffing levels are determined?

    From the management perspective.. as few as possible Jim
  10. lansford

    Side Projects

    If you are smart enough, dumb enough or you have enough of a stomach to have stayed with a major company ( chemical, utility, oil and gas etc) for 30 years you could walk away with $2 M 401 K and almost a six figure per year defined benefit pension. A number of people in this group have never...
  11. lansford

    Girls in STEM is failing both girls and STEM?

    The worst reason for a female to go into engineering is because "they are good in math and science in High School" Where is the mechanical aptitude? Coding and software are better choices. All you have to do is ask yourself ..How many young girls ask for toy electric trains for Christmas...
  12. lansford

    Adapting a 60Hz trasnfomer to 50Hz

    Just as a comment, at our mining facility we had a number of large old 25 cycle transformers that were operating fine for many years on 60 Hz. Jim
  13. lansford

    Naming a consulting company

    Our EE consulting firm in Pa. has the same name as a fitness supply company in the SE USA and we had no problems, although they do want our domain name. JIM
  14. lansford

    LV & Single Phase Arc Flash

    It is common knowledge and often noted that IEEE 1584 does not apply to LV single phase systems and the results are conservative for example 240 volts three phase systems sourced from "small transformers" as well. Plant electrical personnel quickly loose confidence in arc flash studies (labels)...
  15. lansford

    Series ratings application for utilities

    It is also not uncommon practice in utilities, that if a CB is over-dutied and if the actual fault current is above the CB rating that the CB (as controlled by the CB relay) is blocked from tripping and the upstream CB operates. Assuming the upstream CB is rated for fault current. Jim
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