motor problems with 3.5 wtc 2 motor drive

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  • robert lipsett
    Lieutenant, Junior Grade
    • Mar 2010
    • 49

    #16
    I wish I knew if the boat had any power or not when it was out there. I couldn't tell if anything was responding though If it was in thermal the 15 minutes more after a 5 minute rest should have done it again. it looks like a mystery on this one. I am going to try to find the new leak and go again. maybe mon or tuesday before I can try again

    Comment

    • He Who Shall Not Be Named
      Moderator
      • Aug 2008
      • 12253

      #17
      Sounds good. Next time, run the boat hard, but close in to shore as you walk alongside it at the waters edge. If it goes dead in the water and the rudder and other control surfaces can still be wiggled, then you can assume its the thermal trip.

      Good work, Robert. You're keeping up your end of the deal.

      Give me the gory details on the source of leak ... and don't be shy about asking for parts.

      David,
      Who is John Galt?

      Comment

      • robert lipsett
        Lieutenant, Junior Grade
        • Mar 2010
        • 49

        #18
        Well I discovered the source of the flooding and it was the starboard motor seal. The starboard seal was leaking three times as much as the port seal and pushrod seal leak combined. After taking it apart there was some surface rust on the shaft that wiped off with a towel and there was no evident pitting. I polished the shaft up and it was smooth and shiny and replaced the seal. A quick pressure test this morning and no bubbles. Well off to the pond I went today and I was running it hard for about 15 to 20 minutes and the boat came to a halt. about 30 seconds later it surged for a few seconds and ground to a halt. I then walked out to the boat and my snort system was functional and my servos were moving there rudder and dive planes. So now I know the boat isn't losing battery power, I made sure of that by buffing up all the posts screws and connectors. I could feel heat coming from the motors and the controller. The metal mounting platform was hot from possible the two motors and the controller. I am wondering if the motor heat is being conducted to the controller and making the controller over heating worse. The motors have 7v stamped on them but I have been running an 11.1 lipo battery. I have reduced the pitch of the props originally per meriman's suggestion because earlier attempts with a smaller mah battery caused so much heat in the battery compartment that the cap was blown off and caused flooding which sank the boat. The boat moves at a slow walking pace at almost full power so I have to really push the engines to get that speed out of them. the smaller batter was a 3300 mah battery and the larger one is a 5000 mah battery. the larger battery was not too warm. in fact I have had airplane batteries heated up more then this battery was. the 3300 mah batteries were for airplanes and after two trips for the sub they were useless for flying. not strong to keep the plane in the air let alone boost the plane past 80 mph. I only include this information to give a better picture of my problem that I am facing.

        Comment

        • robert lipsett
          Lieutenant, Junior Grade
          • Mar 2010
          • 49

          #19
          I finally had time too make my modifications to the subdriver unit. the esc is now mounted at the opposite side of the subdriver away from the motors. A minor dumb mistake occur while working on the wtc, I mounted the servo arm one tooth set off on the rear dive plane, I noticed this but since most of the running was going to be on th esurface and I was really trying to do a motor test I figured that adjusting the forward planes higher for a rise would compensate for the error. And now on with the show. Full throttle to move the lead sled to a walking speed. All seems good for the first 7 minutes, do you know how boring running a submarine is on the surface ,when someone walks up behind you and asks if your submarine will dive. Tanks vent a little down on the forward planes and under she goes yaaaaaa. Hey that felt good and I brought it back to the surface fairly quickly, lets do it again. A little more down forward planes. Wow that thing went under quickly. I lost sight of it!! All Stop and wait for it bouyancy to surface the boat. 30 seconds later where is it, oh noooo!!!. Emergency blow! 3 second burst. Pop sitting on the surface like nothing happened, I guess dave does know what he is talking about when he designs a subdriver. The badly adjusted rear plane made me dive very fast and I think I got hung up a little under water or I was a lot deeper then I thought. Full throttle on the surface again and at the 15 minute mark the engines cut out again. I have full radio control but no motors. 15 second wait and I have a few second burst of power. I have had multiple burst of power after a short wait period unlike when the controller was mounted directly under the motors. I need some ideas on how to cool this controller before I go to my plan z mode of removing the controller from the wtc and using it in the free flood area of the sub to have it liquid cooled. Where I will fabricate a mounting that can be quickly connected or will be out of the way of the dog bones I do not know. I might have to knock out one of the unused pushrod seals to pass the j connector into the wtc to power the radio and also to run motor wires through. I am looking for some more reasonable ideas before I go to a drastic procedure

          Comment

          • He Who Shall Not Be Named
            Moderator
            • Aug 2008
            • 12253

            #20
            Replace that 11.1v battery with a 7.4v unit and the motor heating will go away -- the over-heating extends to the ESC and it shuts down on you.

            David
            Who is John Galt?

            Comment

            • robert lipsett
              Lieutenant, Junior Grade
              • Mar 2010
              • 49

              #21
              Well the 7.2 volt battery finally arrived and I have had a window of opportunity to test the sub again and its controller. My rear dive plane pushrod is sticking and is jammed in a neutral position which shouldn't be too much of a problem since I will be testing the controller running on the surface. Both props do not start spinning at the same time so I am going to have to investigate if one is binding a little more then the other one. I ran full out on the water for 30 minutes until the battery went dead, a 5000 mah battery. I tried to dive the entire time using only my front planes but was unable to force it under water after I flooded my ballast tank, I might have to try getting some new props with the regular pitch in them. The props I have on right now have a reduced pitch because the battery overheated once with the higher voltage battery and blew the cap off the battery compartment. With the reduced voltage I might be able to run the normal prop blades without heating the battery up since this one felt room temperature after the run. The thing that worries me was the battery ran dead in 30 minutes but there was some extenuating conditions. one was that I had a servo in a stalled condition and the other was that I stupidly left the snort system operating pumping throughout the 30 minute run. Its starting to get a little too chilly to fetch the submarine now, hopefully I will have one more run in the pond before it gets too late in the season.

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