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Recent content by MikiBg

  1. MikiBg

    Voltage and current THD of solar inverters

    Hi all! I was dealing with manufacturer's data about THD at solar inverter's output, in order to use it for harmonic load flow calculation. It wasn't clear whether voltage or current THD is specified. I have searched for other data sheets from different manufacturers, and it looks like THD of...
  2. MikiBg

    Thermal effects of short circuit currents according to IEC standards

    Dear Mr Che Kuan Yau, Thank you for feedback and be free to comment further. Ik which I mentioned is not steady state current from IEC60909, it is short time withstand current from IEC60694, related to duration time tk and, as I said, practically the same as Icw, only for MV applications, and...
  3. MikiBg

    Thermal effects of short circuit currents according to IEC standards

    Hi all! Couple of questions about the subject. Low voltage: Relatively new IEC 61439 standard defines rated short time withstand current Icw. It is the current which equipment or assembly can withstand for period of time given by manufacturer. Icw shall be equal to or higher than the prospective...
  4. MikiBg

    Thermal effects of short circuit currents according to IEC standards

    Hi all! Couple of questions about the subject. Low voltage: Relatively new IEC 61439 standard defines rated short time withstand current Icw. It is the current which equipment or assembly can withstand for period of time given by manufacturer. Icw shall be equal to or higher than the prospective...
  5. MikiBg

    Shunt trip coil controlled by electronic protection unit

    Mystery solved by browsing other files. A terminal I was referring to serves for connection of control voltage to additional (optional) module which can be controlled remotely by communication interface. This module acts on shunt trip coil. Of course, there is another terminal for traditional...
  6. MikiBg

    Shunt trip coil controlled by electronic protection unit

    Yes, that's why I am asking. In this way CB will not be controlled remotelly, but locally by protection unit providing control voltage to shunt trip coil.
  7. MikiBg

    Shunt trip coil controlled by electronic protection unit

    Hi all. There is ABB Sace Emax 2.2N circuit breaker with Ekip dip LI electronic protection unit. It contains a terminal for connection of control voltage to shunt trip coil via NO contact controlled by protection unit. Since protection unit must cause CB to be opened in the case of fault...
  8. MikiBg

    Altivar 630 starting torque

    Hi all! I'm currently dealing with Altivar 630 VFD and wondering how to find out starting motor torque, because no such parameter is available. Is it implicitly determined by low (starting) frequency and V/f ratio, regardless of control mode selected? Is it related to acceleration time and...
  9. MikiBg

    Altistart 48 motor leakage protection

    Thank you, jraef. Can you, please, recommend me some types available on European market with this protection built in?
  10. MikiBg

    Altistart 48 motor leakage protection

    Hi all! Is there any leakage/residual current protection implemented in Schneider Electric ATS48 soft starter, in steady state, after start? I haven't found anything about it inside the manual. We need a protection equivalent to RCD, i.e. switch off the motor in the case of relatively small...
  11. MikiBg

    Impedance in parallel with surge arrester

    Thank you all, specially cuky2000. I suppose they meant on what he is referring to as ZORC.
  12. MikiBg

    Impedance in parallel with surge arrester

    Hi all! Connection of impedance in parallel with surge arrester at 36/0.4 kV power transformer terminals is required by tender documentation. What is the purpose of this impedance and how it should be dimensioned? Regards, Miki
  13. MikiBg

    4 wire Pt100 probe to 2/3 wire temperature controller

    Thank you for advices. Regards, Miki
  14. MikiBg

    4 wire Pt100 probe to 2/3 wire temperature controller

    Hi all. We have 4 wire Pt100 probe for submersible pump motor protection and temperature controller which supports 2 or 3 wire measurement installed on the site. What is the best way to adapt the probe to controller? I have found some drawings online suggesting 2 wire connection of 4 wire probe...
  15. MikiBg

    Ambient air temperature for underground cable sizing

    One only per IEC, determined by surrounding medium.

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