Search results

Search Forums New Posts
  1. Fish4Fun

    Selecting PWM Freq for Speed DC Motor Control

    Thanks Kris! Your points are, as always, salient and tend to "tidy up" many of my conflicting thoughts. I am 100% confident that a slow and methodical approach with a recursive reading/searching/reading loop would eventually yield a solution....but this project is an attempt to merge two hobby...
  2. Fish4Fun

    Selecting PWM Freq for Speed DC Motor Control

    Hey Chris! Thanks.....I was foolishly attempting to avoid a buck converter topology....**hoping** the motor's inductance would somehow "magic" a simple chopper into a speed control....because of the high current under load, I was thinking a buck converter might not be a great choice....Before...
  3. Fish4Fun

    Selecting PWM Freq for Speed DC Motor Control

    Ok, so after thinking a bunch, writing several replies that required me to think more...deleting them..thinking more....finally, I just bread-boarded up a similar circuit (that is, it is pretty much the same except for the components, voltages and motor, lol)....anyway, Using a single IRLZ34, a...
  4. Fish4Fun

    a more simple request (was solar / relay / timer control thread)

    Hey Henry! It looks like you are in good hands, so I am not going to attempt to side-track your current path too much...but as you have been re-thinking this, and it is obviously very important to you...I still think you might consider a slightly different approach.... If you define some value...
  5. Fish4Fun

    Function Generators

    Hey Sinewave! I personally have never really found a need for a dedicated function generator, so perhaps others might give better insight....I guess "cheap" is relative...
  6. Fish4Fun

    Low Pass Filter design

    Hey vin vino, Welcome to EP! Is this a strictly analog circuit? It would be best if you posted a schematic AND if the schematic does not clearly illustrate the purpose of the circuit, then you will likely need to give some details about the circuit's purpose. From the very few details you...
  7. Fish4Fun

    Any recommendation for project?

    As far as a "virtual" USB keyboard goes that could be a fairly trivial project or a real whopper depending on how you decide to approach it. On the one hand it would be fairly trivial to use a standard USB to Serial Port interface and have a uController act as your keyboard....on the other hand...
  8. Fish4Fun

    Selecting PWM Freq for Speed DC Motor Control

    Arouse1973, I don't....but I can....lol. Just a simple low-side chopper is all I am thinking about......never mind :-0 Here ya go... Not sure if i should add a small inductor to limit the in-rush current to the Capacitor Bank/motor...or if I did add one what might be a reasonable value ...I...
  9. Fish4Fun

    Selecting PWM Freq for Speed DC Motor Control

    What I have is a 120Vdc brushed, 16-field "surplus" motor in the ~1.5hp range @~18krpm with a date of mfg of 1978. What I am working on is a belt-drive spindle for a CNC router where the spindle speed needs to be variable from ~1krpm to ~6krpm, the belt reduction is 3:1. This is a one-off...
  10. Fish4Fun

    Looking for a small, low rpm, higher torque motor. Help please?

    Hey Madsalts, Welcome to EP! I am in 100% agreement with everyone else on 1) Stepper Motor 2) Geared DC motor or 3) a Geared Stepper Motor....Unless you have serious positional accuracy issues I cannot see you requiring an optical encoder....In my CNC hobby I have little trouble holding +/-...
  11. Fish4Fun

    Wanted: 5X 100w 20v to 30v Zener diodes or eq needed

    WOW. That was an in-depth read. The PDF linked by the OP is a fascinating reminder of how electrical issues were solved before digital circuits and modern power semi-conductors were cheap and reliable....WOW Fish
  12. Fish4Fun

    Regarding water pump automation

    Rakesh16, If this condition is met, then the other 4 conditions are moot. I, on the other-hand, am far more interested in a pump that does NOT stop when the power supply faults ;-) I think what you mean is that you want the pump to respond based on the state of various sensors. You need to...
  13. Fish4Fun

    looking for circuit designer for a youth project

    Jakob Kaye, Welcome to EP! There are many, many existing "electronic kits" already on the market....Not saying there isn't room for another, but "LED based and battery powered" certainly would not distinguish a new kit from the existing field. The problem I see is that LEDs on the one hand...
  14. Fish4Fun

    need help going green and willing to pay for help! solar / relay / timer control

    Henry, Sorry for seeming obtuse, but in subsequent posts you have given more information about your solar array//inverters and this information is VERY important to achieving your goal...This little "tid-bit" fundamentally changes the problem: This is the key-part most of the posts thus far...
  15. Fish4Fun

    need help going green and willing to pay for help! solar / relay / timer control

    Henry, I can think of several scenarios that might "work", but at the end of the day what you want is very close to an existing product.....a UPS (Uninterruptible Power Supply)....Except one small caveat, you want the UPS to use the mains for "back-up" and your solar panels as the primary power...
  16. Fish4Fun

    need help going green and willing to pay for help! solar / relay / timer control

    Hey Henry! Welcome to EP! Hrmmm, I think this is something that could be "designed" fairly easily....as for actually "making it" that might be a different matter, perhaps I can help, but for now, I will think on it....and wait a bit to see what others suggest.... Fish
  17. Fish4Fun

    Optocoupler stays on

    HowlingGoatBoy..... You used a TIRAC optocoupler... TRIACs are only good for "turning things on" not so much for turning things off.....the way TRIACs//SCRs (Thyristors) work is that a relatively small signal "turns them on" then they stay on until the current drops below a particular...
  18. Fish4Fun

    Light Controller via Internet

    There are existing mass-market devices already in existence....I got one for my wife for x-mas last year (~$50.00) ;-) Unless you are just a glutton for punishment you will likely save yourself a bunch of time and $$ just buying one. Fish
  19. Fish4Fun

    Optical Encoder diagnostic

    adel2014, Are you familiar with servo motors in general? Most modern servo motors are built using 3-phase motors with an external driver and the encoder functions both as rotor position sensor and commutation sensor, though there are plenty of 3-phase servos with independent rotor position...
  20. Fish4Fun

    Building a Custom Cell Phone

    Hey Don Egipcio, Welcome to EP! One of the problems with relatively mature, highly integrated devices is that it can be very difficult to to modify them and actually increase their usefulness/appearance; having said that, the technological evolution of Cell Phones is happening so fast that it...
Top