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  1. S

    shared battery charger with diodes

    I suggest using "ideal" diodes. A 2-component circuit readily available as modules on ebay.
  2. S

    Generator AVR options

    Hi. Can anyone advise on finding an AVR for a very basic 230Vgenerator. It has 3 power phases and a single brush connected rotor winding. There is some residual magnetism for self-starting. There is no PMA or auxilliary windings. TIA Shane
  3. S

    Alternator Field Winding Question

    You could use an adjustable boost converter to provide the exciter power.
  4. S

    3D CAM, servo or stepper ?

    Absolute of incremental, I don't yet know, but even incremental will avoid missed steps (of steppers) under load.
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    3D CAM, servo or stepper ?

    Hi. Having just bought a 3D measurement machine with a working volume of about 1m^3, for conversion for additive and conventional machining, I would appreciate some advice. The machine currently has 3 servo-motors with tachs and position strips. I intend to use an Arduino to control position...
  6. S

    RS422/485 and ground wire.

    Data is sent between the two conductors, but if there is any significant difference between 0V at each end, you will have problems. Low at one end must be below the low threshold at the other, it is not isolated differential as Ethernet is. I have run RS422 over 50m, using the ground wire to...
  7. S

    60 GHz rf meters

    What are considered "safe" levels, and based on what ? We really don't know what the short-term effects of RF of any frequency are, never mind the long term effects. Life has had millions of years to "evaluate" naturally occurring EMR. We have had less than 100 years to evaluate man-made EMR.
  8. S

    Puzzled, basic flyback converter

    Hi. Can anyone shed light on this trace ? A very basic flyback converter, channel 2 is the mosFET drain voltage, channel 1 is the transformer output. rectifier with 4ohm loadWhy am i seeing ringing on the output during the ON phase of the primary ?. If I short the (schottky) diode, the...
  9. S

    IR IMAGING DEVICE on the cheap

    I would like to buy/build a thermal imaging camera for marine casualty searches, but I suspect that is a whole different ball game.
  10. S

    Domestic amp keeps blowing 3.5amp fuses

    The most common faults in old electronics are the electrolytic capacitors. They will degrade at a fairly predictable rate, gradually losing capacitance, then go short circuit. Overvoltage will cause an immediate short circuit. They often, but not always, form a bulge on one end.
  11. S

    1000 watt zvs induction coil drawing too much when I put a crucible in it.

    1kW at what voltage ? P = V x I. 7 amps to short circuit ? If it is 24V, then at full power it will draw 40A, probably more (Chinesium almost always performs well below stated efficiency). Is your power supply up to that ?
  12. S

    Electromagnet vs Neodymium magnet

    Be aware: Creating a permanent magnet by discharging a capacitor: This will cause a decaying oscillation, with the inductance of the magnet and the capacitance as the resonant circuit. If using a polarised capacitor, that could kill the capacitor. Best to put a diode in the circuit to prevent...
  13. S

    K40 Laser Cutter Upgrades

    I suggest that the hole in the box would be useful, and given that the laser is focused quite close to the nozzle, the power density at desk level would be quite low. I wonder if a kit is available that would facilitate an existing X-Y table. I have a CNC router which I would like to convert...
  14. S

    Driving a high power semiconductor laser

    What is involved in driving the higher power (kW) semiconductor lasers ? I am interested in building a system, but precise power control isn't needed. I would start with a much lower power one, maybe 100W, initially without even focusing the beam. Does anyone know of a fluid or gel that is...
  15. S

    Weird PC problem

    Hi. I have a PC which seems to collect water out of the air. Water has a habit of dripping out of the power inlet, and PSU fan sprays water inside the box. This is a 750W PSU, running off about 238VAC (mains power is unusually high), but the FSP power supply IS rated to 264V. Other 750W...
  16. S

    Using An Oscilloscope

    As long as you don't connect the probe ground to a point that isn't mains ground, you should be OK, BUT, you may find that some of the points that you want to probe, have a floating (relative to mains ground) reference. If your scope allows you to add/invert inputs from two probes, you can do...
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    PCs blowing up

    I would be very surprised if it was overclocked, and I am sure that putting mains on a fence IS illegal, even if it is within a farm's boundary. Two machines died just from being plugged in at that location. They had been run elsewhere. A audible spark and smell of fried chips ! A very...
  18. S

    PCs blowing up

    Hi. An interesting and frustrating case: A friend has problems with newer PCs blowing up, even with a UPS. The most recent one leaked water after the event, so I am presuming that it has a water cooled CPU (or PSU ?) It is a gaming machine, so high power consumption and dissipation. We...
  19. S

    3-phase PWM

    Does anyone know of a chip that generates a multi-phase (interleaved) PWM, with the PWM controlled via SPI/I2C/CAN or other serial interface ? I want to build a multi-phase flyback converter to dump energy across 3 isolation transformers (common output). Multiphase to reduce input current...
  20. S

    PNP Transistor to Drive LED

    Ditto.
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