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  1. Alec_t

    help with IR2110 chips

    I think it does. If the coin is between the magnet and the coil surely it will experience the vector sum of the coil-generated field and the magnet's field? That sum is changing because the coil-generated field is changing. The change in the sum won't be much though, if the magnet's field is a...
  2. Alec_t

    help with IR2110 chips

    If you draw current from your coil, that will produce a changing magnetic flux through the coil. Since the penny would experience that flux change there would be eddy currents in it (albeit perhaps not significant in the grand scheme of things).
  3. Alec_t

    help with IR2110 chips

    In that case perhaps you could experiment with an air-cored coil for comparison?
  4. Alec_t

    help with IR2110 chips

    Not strange. Inductors don't obey Ohm's Law. Does that mean with the coil short-circuited? Your new readings indicate that the coil inductance when using the 20 Ohm load is less than it was when using the 100 Ohm load. This is likely because the higher test current is causing partial magnetic...
  5. Alec_t

    Capacitor explodes on PSU

    Welcome to maker.pro! Have you checked that all diodes in the bridge-rectifier are still good? A shorted diode would cause destruction of any downstream electrolytic cap.
  6. Alec_t

    help with IR2110 chips

    I don't know how your coil is mounted now, but if you used a longer bolt or threaded rod as the core, instead of the present bolt, wouldn't that allow simple screw adjustment of coil-to-magnet spacing?
  7. Alec_t

    help with IR2110 chips

    Good luck!
  8. Alec_t

    help with IR2110 chips

    Ah, the joys of having a ferromagnetic core for the coil. Probably one reason why other designs use air-cored coils :) .
  9. Alec_t

    help with IR2110 chips

    With the chain you are reducing the magnetic reluctance between the magnet and the target paper clip, i.e. effectively extending the magnet and reducing the magnet-target gap. That's surely the same as moving the target clip closer to the magnet to reduce the gap?
  10. Alec_t

    help with IR2110 chips

    Do you have any evidence that adding a 2mm thick ferromagnetic coin to the magnet face will be an advantage over simply moving the coil 2mm closer to the magnet ?
  11. Alec_t

    help with IR2110 chips

    Lucky you didn't glue yourself to the wheel :)
  12. Alec_t

    help with IR2110 chips

    Putting pennies in the gap will introduce eddy-current losses. No idea how significant they'd be.
  13. Alec_t

    help with IR2110 chips

    Both meters claim to be true rms and the first mentions non-linear loads, so hopefully would give a reasonably accurate voltage measurement. With 20.9V rms across 100 Ohms the resistor would be dissipating over 4W. Not surprising it got hot!
  14. Alec_t

    help with IR2110 chips

    How are you measuring the AC volts? I ask because general purpose digital multimeters usually give RMS readings assuming the voltage is sinusoidal and fairly low frequency. In your case the waveform is probably not a true sinusoid and the frequency may be higher than the meter was designed for...
  15. Alec_t

    help with IR2110 chips

    A lot more, wth the present design. If it were me I'd be aiming for a coil with fewer turns, hence less inductance. The voltage a coil generates is proportional to the number of turns, but the inductance is proportional to the square of the number of turns.
  16. Alec_t

    help with IR2110 chips

    I was working on the basis that each pole, whether N or S, produces both a +ve peak and a -ve peak in the coil signal because the coil's bolt diameter is much less than the magnet diameter and there were gaps between poles. That means one signal cycle per magnet, making the signal frequency...
  17. Alec_t

    help with IR2110 chips

    That should increase the output voltage of the coil, since the magnetic flux change will be greater as a magnet passes the coil. Somewhere on line I read that generator efficiency varied as the inverse fourth power of the air gap; but the coil involved was a pancake type in a different magnetic...
  18. Alec_t

    help with IR2110 chips

    By my reckoning, that indicates a coil inductance of ~105mH, if the coil resistance is 7 Ohms.
  19. Alec_t

    help with IR2110 chips

    If that's the open-circuit voltage, what do you get with, say, a 100 Ohm load resistor connected across the coil?
  20. Alec_t

    help with IR2110 chips

    This calculator might be a better bet, except that it seems to be for air-cored coils only.
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