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Hi sushilksk, "Magnetic flux outside the core" is the flux that leaks from the core when it saturates. The attached figure shows the magnetic flux leaving the upper part of the core and returning through the lower part. In general, the path of this magnetic flux includes the transformer tank...

Thanks guys for your thoughts so far! I think the attached waveform will clarify exactly what I'm asking about the "zero offset" of the inrush current. Could this phenomenon be caused by the magnetic flux outside the iron core during transformer energization? Cheers, Herivelto S. Bronzeado...

Sorry guys, I didn't make myself understood. Perhaps is due to my "native" Brazilian English. I'm not referring to the peak inrush current but its "zero". I know that the zero of the inrush current is not ZERO due to the asymmetry of the hysteresis cycle during energization. My question is...

Hi Guys! I have observed a "zero offset" in transformer inrush current waveforms. Some researchers think this "offset" is due to saturation of the current transformer used in the measurements. However, this "offset" has also appeared in transformer energization simulations. Does anyone may...

Just to think. https://res.cloudinary.com/engineering-com/image/upload/v1725071394/tips/Neutral_Current_xhzo4a.pdf Cheers, Herivelto S. Bronzeado Brasília, Brazil https://www.linkedin.com/in/heriveltobronzeado/ https://www.researchgate.net/profile/Herivelto_Bronzeado

Thank you guys for your imputs so far! Cheers, Herivelto S. Bronzeado Brasília, Brazil https://www.linkedin.com/in/heriveltobronzeado/ https://www.researchgate.net/profile/Herivelto_Bronzeado

Hi folks! We are preparing a bid to a big water pump project that includes 6 synchronous motors from 5 MW to 13 MW. I wonder if somebody could give me some informations about the advantage/disadvantage in choosing the voltages to feed the motors: 6.9 kV or 13.8 kV? Thanks in advance. Cheers...

Hi Folks, See annexed what I have got in the J&P Transformer Book. Cheers, Herivelto S. Bronzeado Brasília, Brazil https://www.linkedin.com/in/heriveltobronzeado/...

Hi folks, In a simulation of energizing two similar transformers at the same time, the inrush current is not twice the value of the inrush current of just one transformer (in the same conditions). I wonder if the experts could give a explanation on that "phenomenon". Thank you! Cheers...

Hi davidbeach, In the company I worked for, there is a electrical system on 69 kV that are supplied by a transformer wye-delta 230/69 kV. A zig-zag transformer is used to give a ground reference to the delta system (69 kV). When the zig-zag transformer is out of service, the delta system...

Hi folks, If the electrical system is floating, how can the voltage (to "ground") will normally be measured? Cheers, Herivelto S. Bronzeado Brasília, Brazil https://www.linkedin.com/in/heriveltobronzeado/ https://www.researchgate.net/profile/Herivelto_Bronzeado

Tony2802 Please, have a look in Cigre Technical Brochure 568 - "Transformer Energization in Power System: A Study Guide", February 2014, Report number: TB 568 ISBN : 978-2-85873-263-0 Cheers, Herivelto S. Bronzeado Brasília, Brazil https://www.linkedin.com/in/heriveltobronzeado/...

Hi RRaghunath, Thank you for your imputs. Sorry! I have no experience on synchronous motors running as I was out of the Project when it started to operate. I have just returned to it. The motors that are running just now are 6,9 kV synchronuos motors from 2.2 to 13 MW. I will see how they...

Thanks Keith, for correct me! Do you think we will be happy on that? Cheers, Herivelto S. Bronzeado Brasília, Brazil https://www.linkedin.com/in/heriveltobronzeado/ https://www.researchgate.net/profile/Herivelto_Bronzeado

Thank you Gr8blu! So far, I think we are heading to 6,9 kV synchronous motors. Cheers, Herivelto S. Bronzeado Brasília, Brazil https://www.linkedin.com/in/heriveltobronzeado/ https://www.researchgate.net/profile/Herivelto_Bronzeado

Hi Keith, I'm afraid but I think you are (politically) right! Cheers, Herivelto S. Bronzeado Brasília, Brazil https://www.linkedin.com/in/heriveltobronzeado/ https://www.researchgate.net/profile/Herivelto_Bronzeado

Dear che12345 (Electrical), Great post. Short and Straightforward. I realy appreciate it. Thank you! Comments: ... 3. Starting current (high). Consider VD 150km // (low). 4. Starting torque (low) // (high). - Remember that synchronous motor starts as a induction motor ... 6. Running Pf...

LionelHutz, Thank you for the good advise! I hope the first equipment has been well specified. Cheers, Herivelto S. Bronzeado Brasília, Brazil https://www.linkedin.com/in/heriveltobronzeado/ https://www.researchgate.net/profile/Herivelto_Bronzeado

Hi LionelHutz, I was out of the Project since 2016 when those motors (2x13 Mw) was started. The solution was just put a dedicated transformer for each one. Now, I am returning to work in the Project in order to pump doubling. Cheers, Herivelto S. Bronzeado Brasília, Brazil...

Thank you davidbeach and bacon4life to initiate this discussion. Cheers, Herivelto S. Bronzeado Brasília, Brazil https://www.linkedin.com/in/heriveltobronzeado/ https://www.researchgate.net/profile/Herivelto_Bronzeado