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. markjp

    Step Up Transformers

    I have a question regarding step up transformers if someone could help please. I have searched the threads and not able to get an answer to my query. Our plant has 33kV distribution from utility and we need to install emergency standby generators in case utility supply is lost. We are...
  2. markjp

    MV Switchgear Rating

    So does this mean fuses can't be used for fault current limiting? Also can someone please explain what criteria is used for determining if the Internal Arc Withstand rating for switchgear is suitable for an application. From almost all the 12kV equipment I have reviewed the Internal Arc...
  3. markjp

    MV Switchgear Rating

    Hi Marmite, Agree with your comments the RMU should be fully rated, I was trying to combine 2 issues into the one post. I was thinking more about other existing downstream RMU's in the network which appear to be under rated. In LV circuits it is common to use fuses which limit the maximum fault...
  4. markjp

    MV Switchgear Rating

    Hi all , many thanks for your valuable input. The RMU is to be installed on a remote mine site that has it's own power station, there is no connection to the public network. We are comfortable with the fault levels provided. The power system has been modelled using SKM power tools by a...
  5. markjp

    MV Switchgear Rating

    Hi, I have a question regarding switchgear hopefully some one can assist please. We have a project to install a 3-way switch RMU (ring main unit) in an installation with the following power system details: 11kV, 200A maximum load, protection trip setting 200mS, Fault Levels: Ik"=21.7kA 3ph...
  6. markjp

    Transformer for VFD Loads

    Thanks for the feedback guys. If we were to get the transformer fitted with an earth screen, do you think there might be any special considerations with the earth connections? Is it okay to connect the earth screen to the common HV/LV earth bar beside the transformer?
  7. markjp

    Transformer for VFD Loads

    Hi, we are purchasing a transformer and would like some help if possible on deciding whether the transformer should be equipped with an earth screen between the HV and LV windings. The transformer is a conventional 2MVA 11kV/690V Dyn11 unit which will be used to power an MCC switchboard which...
  8. markjp

    Transformer Vector Group

    Thanks for your help guys.
  9. markjp

    Transformer Vector Group

    Have a question regarding transformer vector group selection. There are some very helpful threads on the pros and cons of delta and wye connections, however I was wondering if the vector group of a transformer located higher (upstream) in a power system has any influence for any reason over the...
  10. markjp

    Control Cable Capacitance on Conveyor

    Appreciate the feedback guys. I'm thinking probably go with 110VDC, that way hopefully less voltage drop issues than say 24VDC.
  11. markjp

    Control Cable Capacitance on Conveyor

    I was wondering if anyone may have had some experience with capacitance problems with long control cable runs and PLC inputs. We are working on a project to extend a conveyor from 530m to 1300m. The present control voltage is 110VAC which is used for signalling pull-wire, belt drift,etc. status...
  12. markjp

    Earth leakge relay

    Thanks for your help guys.
  13. markjp

    Earth leakge relay

    I was wondering if someone may have an opinion on the following issue. I have started working on a project for an underground mine and have noticed that the earth leakage relays on the 1000V motor circuits are wired to trip the contactor rather than the circuit breaker. I've have always seen...

Part and Inventory Search

Back
Top