A day in The Cave

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  • MFR1964
    Detail Nut of the First Order

    • Sep 2010
    • 1532

    #151
    David, thanks for the future effort, i have no doubt your contraption will work, but i like to see things in action to learn more.

    Getting the V80 under or up is greatly improved by using the valve and LPB , i do use 12 V, and your remark about the resistor is noted, i'll fix this up.

    Manfred.
    I went underground

    Comment

    • He Who Shall Not Be Named
      Moderator

      • Aug 2008
      • 13598

      #152
      Originally posted by MFR1964
      David, thanks for the future effort, i have no doubt your contraption will work, but i like to see things in action to learn more.

      Getting the V80 under or up is greatly improved by using the valve and LPB , i do use 12 V, and your remark about the resistor is noted, i'll fix this up.

      Manfred.
      Yeah, you're driving that dinky little motor pretty hard with a straight 12-volts. With the SD's I use these in that are rated for 11.1-volt, I outfit the motor power wires (coming out of the MPC -- electronic switch) with an 11-Ohm resister -- drops about 5-volts, which unloads the motor from the otherwise too high input current.

      M
      Who is John Galt?

      Comment

      • MFR1964
        Detail Nut of the First Order

        • Sep 2010
        • 1532

        #153
        How does this influence the pressure delivered by the LPB?, i assume that it will be less, giving me a lower rate of rising the boat, maybe using a lower resistor will drop the voltage less, looking more in the region of 9 volt.

        Manfred.
        Last edited by MFR1964; 10-27-2014, 02:25 PM.
        I went underground

        Comment

        • He Who Shall Not Be Named
          Moderator

          • Aug 2008
          • 13598

          #154
          Originally posted by MFR1964
          How does this influence the pressure delivered by the LPB?, i assume that it will be less, giving me a lower rate of rising the boat, maybe using a lower resistor will drop the voltage less, looking more in the region of 9 volt.

          Manfred.
          Of course your CFM's will decrease with the lower motor voltage. But, as it is, your V80 is rising too fast now, in my book. At the very least, stick a 5-Ohm resistor in there.

          David
          Who is John Galt?

          Comment

          • redboat219
            Admiral

            • Dec 2008
            • 3438

            #155
            David,
            In line with your discussion of using resistors to lower down the voltage, I got a mini air pump I salvaged from a broken sphygmomanoter that I want to use as as snort pump. As far as I know it's only rated to run at 3 volts. My lipo puts out 7.4v. What value resistor do I need to put and where? ( not that electronically inclined)
            Make it simple, make strong, make it work!

            Comment

            • He Who Shall Not Be Named
              Moderator

              • Aug 2008
              • 13598

              #156
              Originally posted by redboat219
              David,
              In line with your discussion of using resistors to lower down the voltage, I got a mini air pump I salvaged from a broken sphygmomanoter that I want to use as as snort pump. As far as I know it's only rated to run at 3 volts. My lipo puts out 7.4v. What value resistor do I need to put and where? ( not that electronically inclined)
              How much current does the motor draw at 7.4-volts?

              Use Ohm's law to solve for R.

              M
              Who is John Galt?

              Comment

              • redboat219
                Admiral

                • Dec 2008
                • 3438

                #157
                Originally posted by He Who Shall Not Be Named
                How much current does the motor draw at 7.4-volts?


                M
                Duh?

                Like i said, electronic naive.

                Only thing I do know that you can't run it on 7.4v or you fry the motor.
                Last edited by redboat219; 10-27-2014, 08:59 PM.
                Make it simple, make strong, make it work!

                Comment

                • redboat219
                  Admiral

                  • Dec 2008
                  • 3438

                  #158
                  Forgot to mention the motor attached is a 130.

                  Did some searching on current draw of this type of motor.


                  Which value do i use, max efficiency or stall?

                  Also for the Ohm calculator, http://www.ohmslawcalculator.com/ohm...calculator.php.

                  Which value do I enter for the voltage, 3 or 7.4 volts?
                  Last edited by redboat219; 10-27-2014, 10:30 PM.
                  Make it simple, make strong, make it work!

                  Comment

                  • Von Hilde
                    Rear Admiral
                    • Oct 2011
                    • 1245

                    #159
                    Ahh, I remember that from the one one day BE&E, about 2 min after the Senior Chief wrote his name on the blackboard. Followed by a short sea story about Einestine and his relatives. No calculators permitted in phase 1, just #2 pencil with an eraser and a slide ruler. Next evolution was the all encompassing Simpson 260 when you could employ all those theories. I guess if you call it a multimeter now days it would be like calling a refrigerator an ice box. Now its just another app on the I pad, Iphone, or what ever the call their personal communicators. The implant chips will be on the market in a couple years with the graphics in the cornea, that will make the new "I" watch look as antique as an old PRC-6 walki talki, compared to the comm gear, the special operators are wearing on their head in today's world
                    Last edited by Kazzer; 10-29-2014, 08:35 AM. Reason: sp

                    Comment

                    • He Who Shall Not Be Named
                      Moderator

                      • Aug 2008
                      • 13598

                      #160
                      Originally posted by redboat219
                      Forgot to mention the motor attached is a 130.

                      Did some searching on current draw of this type of motor.


                      Which value do i use, max efficiency or stall?

                      Also for the Ohm calculator, http://www.ohmslawcalculator.com/ohm...calculator.php.

                      Which value do I enter for the voltage, 3 or 7.4 volts?
                      Jeeezus!!!

                      Just stick a 5-Ohm resister in there and be done with it.

                      Or, is this just another mind exercise?? Look: you're talking to a guy who does stuff. You are a guy who talks about stuff.

                      Snap out of it, Romel.

                      DO SOMETHING!!!!

                      M
                      Who is John Galt?

                      Comment

                      • redboat219
                        Admiral

                        • Dec 2008
                        • 3438

                        #161
                        Well excuse me for asking, Princess!
                        Make it simple, make strong, make it work!

                        Comment

                        • HardRock
                          Vice Admiral
                          • Mar 2013
                          • 1609

                          #162
                          Originally posted by Von Hilde
                          If you just go by zulu time, you'll be up to date all the time. The sun never sets on the British Empire. If you rise with HRH in the mother country, "you will nevah be outuv step" as she would say. Our Navy gave me a rolex GMT back in the early 60s and Ive been locked in since. Most likely thats why I wake up when its still dark. Tigger, my big alpha male tabby, goes by my watch. He litterally bites it when I fail to move, after he pats my facewith his paws, on the first attempt. When the daylight savings switches, he doesnt. Most likely be Christmas before we sync up, and by then the sun starts going the other way. Some people have dogs, and on the other hand some cats have people.
                          I used to work for HRH once. A few nice shooting holidays; targets and ammunition provided. It was fun until the targets started shooting back! Ah, memories.

                          Comment

                          • HardRock
                            Vice Admiral
                            • Mar 2013
                            • 1609

                            #163
                            Some video of the Alpha in the pond yesterday.

                            Comment

                            • HardRock
                              Vice Admiral
                              • Mar 2013
                              • 1609

                              #164
                              Listen to the audio and you'll realise what I have to put up with!!!

                              Comment

                              • trout
                                Admiral

                                • Jul 2011
                                • 3667

                                #165
                                Congratulations, that is beautiful.
                                If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

                                Comment

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