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Hi all. Can you please confirm what is approximately the noise level contribution in a pwoer transformer: i.e. what percentage is due to the tank, how much is due to the fans and how much due to the pumps in a FOA system. Thaks, EddyPach

Hi gents, Do you know a website where I can get a quotation for a SCADA system for digital communication of alarms, protection and so on for 7 transformers? Off now, somebody can calculate an estimate? Will that be a four or five digit number? Thanks in advance

Thanks you all. I want to be able to feed my home-made projects with a reliable pwoer source. I built a few power sources my self, but quite often the transformer blew. Maybe I was overloading the circuit!? I want the power source to be flexible enought to provide from 200 mA to 2 amps.

Who is a good manufacturer of dual 5 and 12 volt power supply? Thanks,

CAn you please tell if there is a website where I can find a diagram to build a home-made alarm system? There may also be a kit to build. What is a cost-effective solution based on, diaphragms, infrareds, motion detectors? Thanks for the info.

Thank you all. So I assume I can safely say that in a power transformer technical questonnaire, the guaranteed negative sequence impedance will be the same as the positive sequence impedance, regardless of the system being balanced or not.

Can you please give me some light to understand the difference between Positive Sequence Impedance and Negative Sequence Impedance? Thanks, EddyPach

Thank you all for the hints. Nbucksa, I want to stop the band so one operator can remove one skin and place another.

Can you please indicate where I can find a good stepping motor manufacturer. I want to move a band that will carry wet calf skins, and want to be able to stop it every 30 seconds for 5 or 10 seconds.

Does somebody know the approximate price for a General Electric Faraday TMMS (Transformer Monitoring Management System)? Is there another suitable make for this kind of device? We know this system can be arranged to include a sort of features and hence it should not be cheap! Thanks for the info.

Yes, Electricpete, yet, if you pay x dollars for a transformer, what do you expect to pay for a turbine (approx), two or three or five or how many times more?

Does somebody know the approximate price rate of a turbine vs. a power transformer, and why this should be so? i know turbines cost far more, but by how much? and why? Thanks for the info.

Does somebody know where I can find distribution transformer specs.? I imagine they woudl very widely from power transformer ones. Greetings,

Basic questions, Can somebody provide the formulas to calculate: the reactance at the OA rating in a 3 phase 126/168/210 MVA, 230 -18 kV power transformer? the three phase capacitance to ground on the high voltage side? the three phase capacitance to grond on the low voltage side? Thanks in advance

A corp. requires a 120/160/200 MVA auto Xfr with H-X=5% and H-Y=21% requirements. However our engineering can only comply with the H-X at 5%, and only provide H-Y = 36% impedance instead of 21%. My questions is what can possibly change with our deviation? Does it matter if the tertiary is...

Can somebody explain what would be the effect of changing the H-Y (high to tertiary) impedance in a 120/160/200 MVA, 260-144/25 kV, three phase autotransformer, from 12% (required) to 26% (per design). The H-X impedance is 5%. Thanks for the info.

Thanks nbucska. Yet,why would it be at 45 deg?

That´s the site, BUsbar. Thank you too, Electricpete

Thank you all.

Is it possible to analyze a transient using the FFT (which is the case with the inrush current when energizing a power transformer)? Or is this technique applicable only to waves with armonic distortion? in other words, we are assuming that the inrush current is a transient and does not generate...