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Recent content by fsmyth

  1. fsmyth

    Running a computer off a generator with a ups?

    Yup. The old Ferrups line was an extremely robust and forgiving UPS. Hated to see them disco'd. Emerson messed up a few more also. :( The present-day alternative is a true on-line backup power system. A bit more expensive to implement. Most have software-defined parameters, and can be easily...
  2. fsmyth

    Mixing small and large batteries

    Look for a PM starter with gear reduction. Pricey, but effective.
  3. fsmyth

    dual band antenna

    No gain. and 30-37.5 degrees has a wider bandwidth.
  4. fsmyth

    Above Ground Fiber Optic Route

    IMHO, both methods are a bit of overkill. Granted, most of our work is in ducts or otherwise enclosed in walls or ceilings, but FO cable is pretty tough. Seems to me that PVC conduit or EMT would be more than enough protection and support in a tray. Or possibly run the stuff rated for direct...
  5. fsmyth

    steam cleaners

    I apologize if this is the wrong forum, but I did not see anything else close. I would like to resurrect an old steam cleaner that someone has removed the pump feeding the coils, and have no idea what to use. Near as I can tell from browsing, the pump needs to be ~200 PSI * 3-4 GPM. Is this...
  6. fsmyth

    dc coil surge supression

    A TVS would be fine, but pricey. The 1N4007/resistor is the better option. Use a flame-proof resistor. Don't cover it up. Makes a great visual indicator. :) We had a whole cabinet full of these (>200 pcs.) and they worked fine. <als>
  7. fsmyth

    Single Phase to 3 Phase efficiency

    How many three-phase loads? If just one or two, the VFD options are simpler. If the loads are variable or greater than 3 or 4, then a rotary phase converter makes more sense. Size it as large as the panel rating if the loads are unknown. The one nice thing about converters is that the more...
  8. fsmyth

    Hobby motor sized tachometer

    If you can find an old 5 1/4" floppy drive, the motor and the electronics are all there. Good for up to about 10 kHz, IIRC. Been a while. :) <als>
  9. fsmyth

    12v to 24v converter

    Yep. Problem here is that Dodge is controlling the alternator field in the ECM, not with a standard regulator. And there is not much room left for an extra alternator in a pickup. :) If it was not a diesel (with 2 paralleled batteries) I would replace the alternator and run a tapped 24v...
  10. fsmyth

    4-20ma help

    Look at: http://hmin.tripod.com/als/andysm/pages/analogs6.html Scroll down to the bottom of the page, and pick out a suitable circuit. Sub your derived voltage for the feedback circuit in the diagram. There are simpler ways, but I do not have handy examples. <als>
  11. fsmyth

    Protection capacitors for stepper driver IC?

    So, put your protection on the motor end. <als>
  12. fsmyth

    12v to 24v converter

    Anyone have a good print for a 24-28v boost converter? Application will be for a vehicular auxiliary 24v system - probably 200 AH or so. Need ~10-15A max. current for charging. I'm thinking something similar to: http://hmin.tripod.com/als/andysm/pages/sw-regs7.html#UPC71 with a bit more smoke...
  13. fsmyth

    30 kHz / 3 Phase signal

    Sort of related to something I am working on now. Will post more recent efforts soon, but there are some old reference drawings at: http://hmin.tripod.com/als/fsmyth/pages/stepdrv3.html <als>
  14. fsmyth

    555 Timer? Input sawtooth 0-8 volts, Output pulse variable duration

    There are a few example circuits at: http://hmin.tripod.com/als/fsmyth/pages/555apps.html Dig around. There might be something that matches your application. <als>
  15. fsmyth

    light/mid load EGT

    Check out: http://dodgeram.org/tech/dsl/FAQ/turbo_faq.htm About half-way down the page, it lists effects and causes. High EGT is associated with a too- rich mixture and mis-matched boost levels. <als>
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