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  1. LiteYear

    IC selection

    Ah okay. As I'm sure you've realised, you're working a fine line between standard off-the-shelf behaviour and full blown uC custom development! I think you're quickly going to exhaust what dedicated function chips can do, but I understand that even the simplest uC requires quite some...
  2. LiteYear

    IC selection

    If I understand you correctly, it sounds like about 100 different microcontrollers will do. Many of them have multiple PWM outputs that can be used to drive the switching element in a DC-DC converter. SPI and I2C is pretty standard, so that doesn't narrow it down much. A PIC may do, as would an...
  3. LiteYear

    Is velcro use acceptable in explosive environments?

    My gut feel is that the energy released in a spark generated by a velcro rip is too small to be a problem. The electrostatic charge is a different problem - our requirements (Group I, Zone 0, AusEx/IECEx) restrict the continuous region of non-conductive plastic to be less than 100mm2. Any more...
  4. LiteYear

    Yzn earthing transformers

    I haven't read 60076-8, but for what it is worth a YNd is generally considered equivalent to a Zigzag grounding transformer, not a Yzn transformer. In particular the Y primary is not necessary. A typical Zigzag grounding transformer has no secondary - it simply has a zigzag wound primary that...
  5. LiteYear

    current limiting

    You will be chasing your tail here a bit. As already suggested, the shunt regulator is doing just what it is supposed to do. But now you want it to not do its job if it's doing it's job too well. Perhaps instead of some sort of latch circuit that tries to disable it on some tricky condition...
  6. LiteYear

    Buck converter calculations

    ...and need to be traded off to suit the design. One guiding equation to determine minimum inductance is: L(min) = (V(in) - V(hs) - V(out)) * D / (LIR * I(out) * f) where: * L(min) - minimum inductance * V(in), V(hs), V(out) - input voltage, voltage drop across switching device in on...
  7. LiteYear

    Grounding the 0V DC reg

    Technically it depends on how the DC is derived from the AC, but generally speaking your specialist is correct - if the AC is connected to PE, connecting the DC to PE can cause a high fault current and other stability issues. The reason being that generally the rectification method means that...
  8. LiteYear

    3 Phase Instantaneous Voltage Conversion from Line to Phase and Vis-Versa

    ...'<' is the polar angle symbol. This is easily verified by linear vector operations. I'll illustrate the first one: LHS = Va = V<0°. RHS = (2/3)*Vab + (1/3)*Vbc = (2/3)*(V<0° - V<-120°) + (1/3)*(V<-120° - V<120°) = (2/3)*(sqrt(3)V<30°) + (1/3)*(sqrt(3)V<-90°) = (2/sqrt(3))*V<30° +...
  9. LiteYear

    MTBF data unavailable

    You could check out failure rate databases like Exida, MIL-HDBK-217 and RAC FMD–97. They list FIT (failure in time) values for all sorts of electronic components. You'll have to do some derivations to extrapolate to PC components, but that's the way safety critical type analysis is done.
  10. LiteYear

    Protection of ELV circuits

    Probably not - when the PSU is first energised there is probably an inrush current to charge the capacitors. The 2A fuse might be sized to accommodate this so anything less might lead to nuisance tripping.
  11. LiteYear

    Protection of ELV circuits

    Yep, in the absence of extra requirements, a switch/breaker on the 240V side and a fuse on the DC side would seem reasonable to me (in Aus land). The only reason to add a switch to the DC side is if the cord is long and integrated with the device it is powering. In that case it is convenient to...
  12. LiteYear

    Is it possible to determine the location of metal object on an inductor cable

    What's an inductor cable? Assuming it's just a long inductor, then sure - in the proximity of the metal object the inductance will change since inductance is proportional to the magnetic permeability of the medium through which the magnetic field passes. This will create an impedance mismatch...
  13. LiteYear

    Audio through a transformer.

    I don't see why you had to short anything together in the first place. I gather the phone has a 4 pin RJ9 socket and the headset has a 4 pin aux plug? Why not just match them up pin for pin? Do you know the pinouts for both devices? A RJ9 handset or a headset is usually wired black (1) and...
  14. LiteYear

    BIL Question.

    One reason is probably Paschen's Curve: at pressures near 1 atmosphere, breakdown voltage of air falls with falling pressure. For example, at 2000 masl, air pressure is about 0.8 atm (608 torr). According to this chart breakdown voltage across a 0.1" air gap falls by about 10kV.
  15. LiteYear

    Shaft Grounding Safety Issue

    Here in the mining industry in Australia it is indeed considered a safety hazard by many. Generally it's unlikely that contact with the shaft would be possible in the first place - the more obvious danger of a rotating member means permanent guards or interlocks are generally required. And...
  16. LiteYear

    Minimal Realization

    Ah I see. Good question. That's definitely something I don't know off the top of my head and would require some study of the balancing algorithm. I'm intrigued, because as you say the reverse transform seems achievable, but not intrigued enough to warrant the time to study it. Please let us know...
  17. LiteYear

    hide IP addresses

    Ah, gotcha, then yes I concur with the other suggestions. I think the neatest way would be to have a simple dedicated router that the two nodes plug in to so they can talk to each other. The uplink port of the router would be connected to the switch. The router could be configured to be a...
  18. LiteYear

    Minimal Realization

    I don't think there'd be any definite relationship - all the states would adjust as necessary to accommodate the space. Is it usual to think of a polynomial fit analogy: suppose you have a signal y(t) that varied with time. Some knowledge of the physics of the signal lead you to believe it can...
  19. LiteYear

    hide IP addresses

    Could you elaborate a little on the network nodes? When you say machine "uses" 2 addresses, do you mean it has 2 addresses or it communicates with 2 other nodes? Are the two addresses on one node (ie. one MAC address with 2 IP addresses) or are they two different nodes? If the machine needs to...
  20. LiteYear

    good C++ compilers

    The gcc chain is available in various compatible guises (eg. Cygwin and MinGW), depending on the environment you want to develop in. Otherwise the free version of Microsoft Visual C++ comes with a compiler that does the trick. There's also Dev C++ but I don't know anything about it. As far as I...

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