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Does the momentary short circuit calculations also called the first cycle calculation???? Can you state why did sometimes its called half cycle calculation??? Does the momentary symmetrical rms current, momentary asymmetrical rms current and momentary asymmetrical peak current based in what...

Why it is important to compute the momentary symmetrical rms current,momentary asymmetrical rms current and momentary asymmetrical peak in the evaluation of CB short circuit ratings? Does the momentary asymmetrical peak short circuit current and the interrupting symmetrical rms short circuit...

Can I ask if the rated short circuit amps in nameplate is the interrupting symmetrical rms current rating? The nameplate has only the rated short circuit amp on the nameplate which is 25kA., with 3 cycles and voltage range factor of 1.0 . How can I know the momentary rating or the making current...

Do you have tables for the short circuit rating of CB in ANSI at IEC used in high and medium voltage?

Do you use safety margin in comparing the calculated fault currents to the Cb rating?what if the safety margin is 330% what does it mean?? Do you have TABLE FOR standard kaic ratings IN ANSI and IEC?? THANK YOU

Hello everyone! How to evaluate CB short circuit rating based on the calculated short circuit current? How many percent must be the calculated fault current compared to CB short circuit rating? Do you have standard CB short circuit ratings table for ANSI and IEC CB? Thanks everyone

How did ETAP solve for the device capability of the momentary and interrupting summary report? Thank You

How did ETAP solve for the device capability of the momentary and interrupting summary report? Thank You

Hello everyone! How did ETAP solve the base value on its short circuit report manager? How can I also solve for the per unit impedance of my transformer if the rating of the transformer is 67kV/13.8kV... my base voltage that I used is 69kV/13.8kV since that is connected in a 69kV/13.8kV...

@ Xnuke so what will I use? low, medium or high? The low, medium and high graph has its own X/R values. I dont have the data of the X/R ratio of transformer and induction motors for my short circuit calculation, thats why I will be using the typical values from IEEE standards, but sadly the low...

Hello everyone! Can I ask what is the meaning of low, medium, and high on the graph of the typical X/R ratio of transformer and induction motor in IEEE standards? Attached here is the picture of the typical X/R ratio. Thanks...

Will I used only the symmetrical breaking current result or the asymmetrical breaking current to compare with the nameplate breaking current? How can I evaluate the result based from the short circuit rating in the nameplate? The X/R ratio is greater than 17

The 69kV line uses a CB which has a rating in IEC standard, while on the 13.8 kV it uses ANSI standard.. So meaning I will do twice short circuit calculations ANSI and IEC?

Thanks Everyone. If I dont have the fault duty of the utility source, what can I used?

Do I need to calculate the asymmetrical breaking current and dc current component and use this in the evaluation of the IEC rated CB? How about if the asymmetrical breaking current calculation is higher as well as the dc current, does it shows that the calculations exceeds the device capability...

Dear Everyone, The system where I did its short circuit calculation has 72.5kV PCB with 25kA breaking current and 65kA making current with 44% dc component rated in IEC standard which is used in the 69kV line, the 13.8 kV line used 15kV vacuum circuit breaker with rated short circuit current...

Thank You @ Kiribanda Thank You for sharing your knowledge and expertise. The nameplate of the PCB used the IEC 62271-100. While using 0.037sec the asymmetrical current exceeds the device capability as well as Idc exceeded. Anyways, the system where I did its short circuit calculation has...

Thank You @ Kiribanda. Attached here are Questions with Regards to the Result of my ETAP short Circuit Calculation. Can you help me which one is correct. Thank Youhttps://files.engineering.com/getfile.aspx?folder=094a44a0-1bc9-41ae-9481-040740f999b5&file=Result_in_ETAP.docx

What Will I do The manufacturer didnt reply? Thank You everyone for sharing your knowledge and expertise

Thank You Everyone, @Kiribanda the maximum closing time, total breaking time, opening time and deadtime stated in the manual are: Opening time : 35ms Closing time : 60 ms Total breaktime: 55 ms Deadtime : 300ms Rated reclosing time : 20 cycles RATED OPERATING Sequence : O – 0.3 sec – CO – 3...