Trying to read up on transferred voltage hazards and cannot seem to understand what the correct solution on this issue. This is similar to thread238-413458. Without using expensive software is there a way to know how to solve the issue.
Typical scenario is an industrial application with the...
Once again thanks for all the replies!! I'm taking all of your comments into consideration and have concluded that ampacity and protection of the control wires is not important in this case, as I've mentioned previously the vdrop is not an issue... @stevenal the cable feeding the circuit is a #8...
I do have some follow up questions. I did the vdrop and there is no issue with it. The issue I'm looking at is that the vendor provided a 30A fuse in the control circuit. Is it common for HV breakers to have a fuse in the control circuit this high? I'm used to seeing 15 as the highest for...
I'm curious to understand how others have determined the ampacity for sizing feeder cables to a 48Vdc control circuit of a 138kV HV circuit breaker. I have the information for the loads in the control circuit in which largest loads are the 2-trip coils and 1-open coil. All other loads (trip coil...
Thank you gentlemen! I'm glad I'm not the only one hesitant about this idea. The PSU vendor mentioned that this should not be a problem but I'm not convinced. I just want to understand more and the theory behind it. GroovyGuy I like your idea about the adjustable power supply! That seems to be...
Hi,
This is a basic question I guess but would greatly appreciate anyone's input. I have an existing DC power supply feeding the existing control system PLC and the loop powered instruments in the field. The PLC requires a change and will now have a higher DC voltage as power supply. Assuming...
Thanks Waross and 7anoter4! Very useful information definitely! Yeah me either haven't really used Y-High leg delta myself. I have seen some of Client's specs that this is not to be used anymore. I thought it was just because it is too confusing, but good to know what the other risks and effects...
I agree with trying to label all the equipment necessary for inspection. But the last I checked IEEE 1584 based their testing produced the formulas from a 3ph model. Sure we can use the formulas for 1ph calcs but this yields high results. I have heard in a seminar that their revamping the...
Thank you for the comments!
I put it in excel and I got the following:
IA = 29.16 <8.21
IB = 25.35 <115.28
IC = 32.54 <-123.67
To get the "<" Angle
I get the imaginary and real individually from IAc as
Real: =IMREAL(IAc)
Imaginary: =IMAGINARY(IAc)
and then the angle will be...
I am trying to solve line currents for a delta delta transformer using nodal analysis but couldn't arrive with the correct answer. The simple way I have done this before is to distribute kVA loads to individual phases then divide by the Voltage / Sqrt 3. Say we 3kVA load on phase AB, 4kVA on BC...
