Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: looking for a pwm

  1. #1
    Fidell Guest

    looking for a pwm

    You may have seen this around the net.
    is it worth buying?


    http://cgi.ebay.com/ebaymotors/30-am...RCHQ3aUSQ3a101

  2. #2
    DaveyJones Guest

    PWM Circuit

    It looks ok, but I'm suspicious of the 30A rating. Anyone tried putting 30A continuously through one of them?

    I used one from Rmcybernetics, it is rated for 2.5A continuously which was fine for my little experiment.
    http://www.rmcybernetics.com/shop/cy...rcuits.htm#A21

    It also has a variable frequency control and little functions for linking them together. If I get my little project working I will be going for one of the very large versions they sell.

  3. #3
    Join Date
    Sep 2008
    Location
    Anchorage Ak
    Posts
    954
    It does work an an inexpensive PWM. I have 4 of them. Do not buy it off e-bay. This is a mass produced DC Motor control. Just Google MX066. That will take you to the same place that the e-bay resellers are buying it. They are around $20.00 there. Also they offer a frequency adjustment kit that is easy to add on for $11.00. You can get about 25 amps out of it if you install a cooling fan in the enclosure that you provide.

  4. #4
    HION Guest

    PWM for now

    Tech at work gave me a working trolling motor controller. It's a 20khz pwm capable of 40+ amps continual. I would not go out and buy one for hho generation, but if you can pick one up cheap because another part of it is shot (motor, mounts, footswitch/slide pot, etc.), it works. Not as good as one with frequency adjustable, but better than nothing.
    Some trolling motor controllers are 3,4 or 5 speed. These are not pwm controllers. PWM controllers are variable speed.

  5. #5
    paulm39083 Guest

    PWMfor HHO

    Afternoon,

    I just found this forum last night and have already read what seems like thousands of posts. Most all is GREAT stuff.
    I live in Florida and yes I am a senior citizen, Not retired , I am a real estate agent in Venice......... paradise.

    ALso I am a mech. eng. and have been trying to use some of what's in my head for a useful purpose. HHO is it.......... or perhaps some other Alternative Energy ......... anyone tired of the Feds and Oil or is it Oil and the Feds ?

    So I wonder if someone could post a workable layout of a PWM in its best use form, with a parts list and enoug instruction so that one could go to Radio Shack , buy the materials and build one in the garage.

    Surely someone on the forum has accomplished this. I have done all the Goolging that I can stand for awhile and thought perhaps this would be the lazy way of getting enough info to get it done.

    By the way , I have built 7 different arrangements of HHO Generators in the past few months, most of them have heat issues, but fair to darn good production. None are very large, most I have used 3" CPVC and limited height to about 10 "

    Not a lot of room, but I need / want to put in the Town & Country but some knuckle head put the engine in sideways and took all the room.




    Paul

  6. #6
    Join Date
    Jul 2008
    Location
    Columbus Ohio
    Posts
    211

    Want schematics.

    paulm39083,

    I've posted two schematics of pwm's on this forum.

    In the "Maintain current" thread is a current feedback PWM that you can dial in the current on a pot, and it will hold that current regardless of the load change. The parts list is posted.

    In the "temperatuer feedback pwm" thread is a pwm schematic that will run the gen full on until the setpoint temp is reached. Then it will pwm to hold the temperature constant. The parts list is posted.

    I am going to post 1 more. This one has the temp pwm, but when the car is stopped, it runs a temp monitor. If the temp falls below 38 deg F, it will turn on a 3 watt resistive heater to keep the gen from freezing.

    I installed the Temp / monitor pwm in my truck on sunday. Works great.

  7. #7
    paulm39083 Guest

    Pwm Plans

    found them both plus one that used your hand written

    schemantic and computerized it ...... nice

    thanks a ton. now the old guy goes to work



    Paul

  8. #8
    Join Date
    Jul 2008
    Location
    Columbus Ohio
    Posts
    211

    current feedback pwm schematic mistake

    All,
    The schematic I posted for the current feedback pwm has a mistake.

    I built one for somebody and started testing about an hour ago. It started to get hot, and the scope showed screwy waveforms, not clean squarewaves like previously.

    The mistake is the 10 meg resistor. It should connect to pin 2, and the other side to pin 5.

    Sorry for the screwup.

    --------------------------------------------------------------------------------

    Here is a parts list for the current feedback pwm, and where to get.

    PART DIGI-KEY P/N COST
    -------------------------------------------------------
    12 VOLT ZENER 1N5349BTPMSCT-ND .40
    500 OHM POT CT2201-ND 2.71
    LM339 LM339NFS-ND .47
    FET IRL1404ZPBF 3.67
    20 OHM 20.0XBK-ND .50
    20 K OHM 20.0KXBK-ND .50
    49.9K OHM CMF49.9KQFTR-ND .30
    (2) 24.9K OHM CMF34.9KQFTR-ND (.60) .30
    1 K OHM CMF1.00KQFTR-ND .30
    133 OHM CMF133QFCT-ND .30
    .01 UF 1460PH-ND .17
    10 MEG OHM 10MQBK-ND .27


    PART MOUSER ELECTRONICS P/N COST
    ------------------------------------------------------
    .01 OHM 25 WATT 71-RH25-0.01 3.76

  9. #9
    HHO King Guest
    Extreme HHO has complete pwm's with built in gauges,fans,switches and relays.

    http://www.extremehho.com

  10. #10
    solo33 Guest

    PWM info

    Another interesting PWM/current limiter can be found at:
    www3.telus.net/chemelec/ you'll find schematic, parts list and PCboard layout. I believe a board is available. It is an improved verison of Zerofossilfuels design. I built it including the board. Completely adjustible and works great. Go to youtube, put "zerofossilfuels" in the search engine.
    Good luck.............

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •