Recent content by xareu

  1. xareu

    Exploring the Effects of Lenz' Law and Magnetic Flux: Is Ferromagnetism the Key?

    One more question related to this topic: imagine you have a circuit consisting of a superconductive closed loop crossed by a time changing magnetic field. In this situation, the circuit is closed so an induced EMF should appear to counteract this magnetic field change. This leads to induced...
  2. xareu

    Use of Capacitors for Generators

    I think Consultant 2 is right. Charging capacitors can lead to rather high currents, so it´s advisable to use smaller ones close to the loads.
  3. xareu

    Electric Fan, when Not Spinning, gets Hot?

    Well, as Merlin said, once the motor is running, current and thus losses are much lower, no need for a big airflow. Did you try oiling the bearings?
  4. xareu

    Electric Fan, when Not Spinning, gets Hot?

    Much simpler and probably true.
  5. xareu

    Electric Fan, when Not Spinning, gets Hot?

    In order to get a starting torque in single-phase asynchronous motors, you need two out-of-phase windings. As you only have one ac source, the phase shift is created by a number or ways: a capacitor (for example in some washing machine motors), shading coils, etc. Once the motor is started, the...
  6. xareu

    Phase voltages in line-to-neutral fault

    I recommend you the group Power System Analysis in Linkedin for more expertise than I have.
  7. xareu

    Phase voltages in line-to-neutral fault

    Well, as you have negative and zero sequences currents, you have negative and zero sequence voltages and armature reaction, thus mmf in the airgap and electromotive force
  8. xareu

    Phase voltages in line-to-neutral fault

    In a L-G fault, when you apply the symmetrical components matrix to the calculation to get the voltages after the currents are calculated, they are affected by the SC in the other phase. One cause is the voltage drops in the zero sequence impedances which in normal balanced conditions have no...
  9. xareu

    Can I use two AC TRs with ONE neutral at sec. and prim.?

    At any rate, this circuit belongs to a "power" rectifier, but I believe that for the 0...10 Vdc the control circuitry isolates the variable 0...10 Vdc from the 24 Vac input
  10. xareu

    Can I use two AC TRs with ONE neutral at sec. and prim.?

    This is a matter of engineering, not laboratory tampering with circuits.
  11. xareu

    Can I use two AC TRs with ONE neutral at sec. and prim.?

    The transformers neutral must be solidly interconnected, without the resistor . Please check neutral earthing schemes. The control voltages are 0-10 V and fed from the controllers. As for the control signal: most probably the internal circuitry of the controllers isolate the 0-10 Vdc from the...
  12. xareu

    Phase voltages in line-to-neutral fault

    What is normally neglected in the calculation is the current in the healthy phases, hence they are "open" compared to the faulty one. But I agree with you, the phase voltajes are the same (if neutral displacement, voltage drops by homopolar currents, and other phenomena are not considered).
  13. xareu

    Can I use two AC TRs with ONE neutral at sec. and prim.?

    The resistor is not advisable. As I explained before, the neutrals must be solidly connected. If you want to protect the circuits (you should), you can used Miniature Circuit Breakers in each phase leg (not in the neutral in this particular case).
  14. xareu

    Can I use two AC TRs with ONE neutral at sec. and prim.?

    As long as the "positive" terminals of the transformers are not connected two (to avoid paralelling the transformers) there should be no problem with the connection you are proposing. Indeed, if you are using a TN scheme, the neutral points should be common and at ground potential
  15. xareu

    Electromagnetic continuity equation

    But if the E field is sinusoidal, ∂ρ/∂t=∂ (ɛ∇⋅E)/∂t is not equal to (∂ɛ/∂t)∇⋅E as in the calculation which originated this thread (leaving apart the rho issue).
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