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steven haskins steven haskins wrote on August 31, 2017 at 6:05 AM:
I am having trouble correlating motor class insulation and its relation to B rise and F rise. For example, can you have a 65 degree ambient with Class F insulation and meet B rise, why or why not?
Admin Reply by: Ver Pangonilo
In IEC 60034-1:2004, Table 10, the maximum ambient temperature for Class B & F is 40 deg.C. The temperature rise are 130degC (Class B) & 155degC (class F). This means that the 65degC is unacceptable based on this IEC std.
Nems Nems wrote on August 30, 2017 at 4:09 PM:
Sir Ver
Good day, im working in hospital facility, voltages in our distribution line are L1N=115v, L2N=120v, and L3N=220v, but the line to line voltage is 230v, QUESTION-what do you think is the problem. any suggestion or recommendation please. thanks
Admin Reply by: Ver Pangonilo
I reckon that your system is Wye ungrounded with unbalance load. Check the current of each line to verify the load of each line. To solve this problem, ensure that you have asolidly grounded neutral.
Alex Bogias Alex Bogias wrote on July 26, 2017 at 1:28 AM:
Hi Ver,

The book you have titled "Introduction to Power System Protection" is not the "Practical Power Systems Protection".

I suspect its from people from Schweitzer Engineering Laboratory (SEL) but I simply can't find it.

If you have any ideas please let me know.

Thanks and regards
Admin Reply by: Ver Pangonilo
In my recollection, I believe that this book was given to us as a reference in one of the training I attended but I could not remember which one.
Pablo Jabajab Jr Pablo Jabajab Jr wrote on July 13, 2017 at 12:28 AM:
Greetings Ver!

It’s my pleasure to have your contact.

I have query regarding the time-curve characteristics of the circuit breakers.

I prepared a circuit breaker coordination considering LSIG trip unit protection from downstream to upstream.

How to prepare time current curve in excel format? Is there available software for this particular requirement? Please advise.
Admin Reply by: Ver Pangonilo
Search my site and, you will see tutorials on how to do time current curve in excel.
Alex Bogias Alex Bogias wrote on May 26, 2017 at 10:29 PM:
Hi Ver,

The book titled "Introduction to Power System Protection" is of interest to me and I would like to purchase it but I believe that is NOT its title.

Do you by any chance know its official title?

Thanks and regards
Admin Reply by: Ver Pangonilo
Try this book
Practical Power Systems Protection
Author: Les Hewitson
Ravi Prakash Ravi Prakash wrote on May 19, 2017 at 2:27 AM:
Sir, I am sorry for not giving all detail about the design of transformer. The detail of transformer are as:
A 2 winding 3 phase transformer of 33kV/440V, 2MVA has short circuit voltage is 6.5%.I have to put the right value of short circuit power in software so that transformer can operate with minimum loss.
I have applied common approach but not getting right value. Please let me know some approach.
Admin Reply by: Ver Pangonilo
Are you trying to design a transformer, want to create a transformer specification or doing a fault analysis using the transformer you mentioned? What are you trying to achieve?
Ravi Prakash Ravi Prakash wrote on May 18, 2017 at 4:26 AM:
I have to know about design of two winding transformer.
SC Voltage
Admin Reply by: Ver Pangonilo
With such a little detail, I am sorry but I could not help you.
Richard Richard wrote on May 10, 2017 at 10:36 AM:
My questions is, if your building has a large load and you are advised by the power provided to have a separate power supply. Who's responsible in providing transformer and KWH meter. Is it the customer or the power provider. Thank you.
BG BG wrote on May 7, 2017 at 2:27 PM:
Hi Sir,

Thanks for the info, but how about cells C10 to C17? Looks like interpolation to me, since values were taken using long time pick-up and instantaneous pick-up, but I think I am missing something. Sorry to bother you, I really wanted to learn this excel stuff. This will be very useful for my PEE TER without using ETAP.

Admin Reply by: Ver Pangonilo
You are exactly right. Having known the two extreme points, the middle points are interpolated between them using the values from column A. Again the only reason for this is to have a smooth curve when plotted.
BG BG wrote on May 4, 2017 at 6:26 PM:
Hi Sir,
It is the one that I downloaded in your website sir.
Here's the path:

Admin Reply by: Ver Pangonilo
The values on Sheet 3 Cells A9 to A18 are arbitrarily selected to provide a smooth curve when plotted. You can select any values you want. All other entries are calculated.
BG BG wrote on May 4, 2017 at 12:47 AM:
I just want to ask something in the attached excel file for Time-current curve, Sheet3, Cells C10 to C17. Are these values interpolated? I also want to know how did you arrive for the values in cells A9 to A18 Sheet3.
Admin Reply by: Ver Pangonilo
Can you provide the link to the article you are referring in your query?
merek merek wrote on March 14, 2017 at 12:46 AM:
Hello, sir!
I don't know how to modelling autotransformer in ETAP. It's possible to modelling autotransformer?
Thank you!
Admin Reply by: Ver Pangonilo
ETAP does not explicitly model auto-transformers.
Dipon Dasgupta Dipon Dasgupta wrote on March 7, 2017 at 11:02 AM:
I'm performing a coordination study on a distribution at my school. I'm not sure how to estimate or calculate the MVAsc or X/R ration of our utility. Please help if possible. Thank you.
Admin Reply by: Ver Pangonilo
The best method is to ask your utility about these parameters.
eng ah.ase eng ah.ase wrote on January 2, 2017 at 12:04 AM:
hi, my sir
iam from iraq electricls eng
i cant understanding the time and current
curve tripping i need pdf examples description prosiduer for the curve if you could help mi
i will be very glad from you and thank to you
Kenzo Simon Kenzo Simon wrote on December 17, 2016 at 11:49 AM:
It's been a long time sir. Gusto ko lang po malaman kung kamusta na kayo? I hope you remember me. It's about 22 years. Sana po wag niyo naman po baliwalain itong message ko sa inyo. Bilang anak ang tanging gusto ko lang naman ay makilala yung tunay kong ama. Napakaimportanteng tao niyo po sakin. Ikaw yung inspirasyon ko sa mga pag aaral ko, na sana isang araw kapag lumaki na ako't nagkatrabaho , hahanapin ko kayo. Sana po mabasa niyo po itong message ko. I am now a 3rd year college student taking up Bachelors Degree in Computer Network Administration. Hindi lang naman po ako simpleng tao eh. I was part of your past sir. I hope kialla niyo yung mama ko, Jacqueline Simon . She said that I can find you in the internet and this is it. I've finally found you. The first time I saw your picture talagang naramdaman ko na po. Luksong dugo kumbaga. Halos kamukang kamuka ko po kayo. Im happy to see you in the picture but yet I want to talk to you personally. Im now 22 years old. I think my age is enough to know this matter. Alam niyo, bilang anak na gustong gusto ko kayong makilala ng lubusan. Lalo na hindi ko kayo nakita man lang sa paglaki ko. I hope you will see this message. This is the only way to contact you personally. This is my email if ever you want to contact me, [email protected] .Mag iingat po kayo lagi. Thank you.
alex cruz alex cruz wrote on December 10, 2016 at 12:06 PM:
gud am sir ver
system voltage of utility is 13200V (L-L) primary, 400V(L-L)secondary, so may question is:
where i point my tap changer to come up to 400V system secondary?
can u give me sample how to bank 250kVA XF to attain my secondary voltage.
thank u
ARIEL PINEDA ARIEL PINEDA wrote on December 10, 2016 at 11:57 AM:
What is the relation of transformer percent impedance to its reactive power capability?
jerald reyes jerald reyes wrote on December 6, 2016 at 9:03 PM:
good day,,,i want to ask that,when we need to put a transformer a building?how much the load limit that we need to put a transformer?
peter marshall peter marshall wrote on October 30, 2016 at 7:07 PM:
where do i ind the regulations appertaining to solar and the grid as far as connection and fitting
Admin Reply by: Ver Pangonilo
It all depends on the location.

Across Europe, solar panels have to be certified to IEC safety standard IEC 61730 and performance standards IEC 61215 or IEC 61646.

Solar grid-tie inverters have to conform to IEC 62109.

In Germany, grid-tie inverters must have a VDE126 certification,
In the United Kingdom, grid tie inverters that produce fewer than 16 amps of peak power must have G83/1 certification, and larger inverters require the much more complicated G59/1 certification.

In the United States, solar panels, solar cables and inverters have to have UL certification. Solar panels must conform to the UL 1703 standard. Grid-tie inverters must conform to UL 1741 and solar cabling must conform to UL 4703 or UL 854 (USE-2). If you are using batteries in your design, the batteries must conform to either UL 1989, UL 2054, UL-SU 2580 or UL-SU 1973.

In Canada, solar panels must conform to safety standard ULC/ORD-C1703-1 and design standards CAN/CSA C61215-08 or CAN/CSA C61646-2, whilst gridtie inverters must conform to CSA C22.2 No. 107.1. Batteries must conform to CAN/CSA F382-M89 (R2004).

In Australia, solar panels must conform to AS/NZS5033, whilst grid-tie inverters must conform to AS4777. If you are planning a stand-alone system in a building, your system must also conform to AS4509. If you are planning a mobile system, for instance in a caravan or recreational vehicle, your system must conform to AS3001.
Sean Szeto Sean Szeto wrote on October 29, 2016 at 12:51 PM:

In the link above page 2, earth fault loop. at the bottom you mention is 81 metres. Zs / Z. But Z already have 25 metres. I think you are saying 81 times Z? which is 81 * 25 meters for maximum length?
Admin Reply by: Ver Pangonilo
The 81m is the maximum allowable length for a 2.5mm2 cable to ensure operation of the upstream protective device. Since 25m is shorter than 81m, the cable size is acceptable.

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