Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 27 replies
  • Subscribers 32 subscribers
  • Views 3674 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Line impedance query

me1899
Hi 


I am looking at a job where a supply to a replacement CT scanner has to be calculated.


The current scanner is fed by a cable with line impedance 0.06 at source end of the sub panel that feeds it.


The new scanner must have a line impedance no more than 0.06 so basically I can't use the way on the current panel.


The client engineer has said to run from the intake and provide a cable calc to prove the line impedance is OK for the new scanner feed (this is D and B).


I am using AMTECH and was wondering if there was a way to output line impedance or if I need to show a calculation another way?


The client engaged a firm to do line impedance tests, and their report shows values measured between L1-L2, L2-L3 and L1-L3, but looks like they did testing at the sub panel and not at the intake.


This is basically like PSCC right? So I can get PSCC from AMTECH, divide by root 3 and work out impedance from there?


Am I on the right track? Assistance would be much appreciated.


Regards


Anisur
Parents
  • 0
    As Dave Z and OMS have pointed out peak current short duration are going to be present.


    The equipment manufacturer should be able to give you a data sheet with maximum demand information, power factor, harmonics and minimum voltage drop. Plus any other relevant information. 


    I would want to know what was on the main LV panel the supply is being taken from to ensure the supply with existing loads can take the big inrush currents without impacting on the volt drop on the supply and the existing loads.
Reply
  • 0
    As Dave Z and OMS have pointed out peak current short duration are going to be present.


    The equipment manufacturer should be able to give you a data sheet with maximum demand information, power factor, harmonics and minimum voltage drop. Plus any other relevant information. 


    I would want to know what was on the main LV panel the supply is being taken from to ensure the supply with existing loads can take the big inrush currents without impacting on the volt drop on the supply and the existing loads.
Children
No Data

Community Rules & Guidelines