Cant we do this?

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  • AndyKunz
    Fast Electric Addict!
    • Sep 2008
    • 1437

    #46
    Excuse me from trying to be helpful! There are several posters here, and sometimes you seem to be arguing with yourself with the contradictions. I thought you were talking to Randy for several of those comments with no quote, as well as the one where you did quote him.

    At what point of adding fets do i need to worry about driving up the gate capacitance to where I need to consider a different driver.
    At the point where gate capacitance, series R, and input power impedance adversely affects rise time of the FETs, causing them to stay in linear mode too long and get hot, or to not turn on/off at the right times causing shoot-through.

    A different driver probably won't make a lot of difference unless somebody is using a crappy one to begin with. A duplicate driver would be better if you're adding FETs. Just make sure you see the gates rise and fall within a few ns of one another. You need to make sure you don't cause shoot-through.

    Also if im understanding rite we could do what they do to us and simply identify the fets reverse engineer the traces and simply use pcb sofware to desing a powerblock with more fets and caps build it and run it with the existing logic board?
    Nothing to reverse engineer, and no need to copy. The hot sections are going to be the same basic schematic that you can find online in lots of places. Just component values will change. You need to read up some more on why the caps are on an ESC there. If you are driving a bunch more FETs you might need more caps to provide the needed voltage and current on the high side FETs.

    Do you have anything in your goody chest that will supply 30 volts @ 100 amps contiuous to a brushed motor.
    No, my old ESCs only went to 90A. That didn't stop people from running them harder, though. And I am down to only about 8 left.

    Andy
    Spektrum Development Team

    Comment

    • Xfactor
      Banned
      • Mar 2009
      • 861

      #47
      Im not in a good mood today I dont have the energy. Yall hold it down im out.Im already saying things that are rude to others so i need to go chill. Andy youre okay.


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      • Doug Smock
        Moderator
        • Apr 2007
        • 5272

        #48
        Wow, thought I was on Jims for a second.


        Emotional awareness (knowing what we feel and why) helps us learn about ourselves and build good relationships. Here are 5 ways to get more in touch with your emotions.
        Last edited by Doug Smock; 05-27-2010, 11:17 AM.
        MODEL BOAT RACER
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        • AndyKunz
          Fast Electric Addict!
          • Sep 2008
          • 1437

          #49
          Originally posted by Xfactor
          Andy forget it you knew i was talking to you. Me and your pal had a spat and u decided to take it upon your shoulders fine man.
          Really? Who is my pal that you're talking about? Really, I'm totally independent of any others around here. I have no idea who you're talking about, or what spat you had.

          You know you were the one that used to make brushed stuff.
          Yes, I know who I am. What does that have to do with this?

          Forget it homeboy its all good. Being black makes for tough skin realize this I was hated when I came out my moma so its all good .No playing or bringing up race but live a day in my shoes growing up as a kid in the south.
          I didn't know you are black. That doesn't matter to me - my absolute very best friend is black. I'm hoping to get out to dinner with Yakubu and his family when I'm in town next week.

          I also used to run a bus ministry for our church through the bad part of Bethlehem. Black, Hispanic, and mixed, and none of them like each other but they're all my friends. And I plan to visit some of them next week too. We keep in touch, and they know color is nothing to me.

          And Wilmer - he's black, and I'd put him on my friend list in a heartbeat. He's a riot! If you ever get out to northern California you gotta hook up with him and Randy.

          If anybody around here has a problem with you being black, it ain't me.

          Notice i let stuff go real quick because boats a therapeudic for me . I need them to keep from snappin on some fool out here in the streets so I wont let u or anyone take that joy from me. Life is bigger than rc boats. These boats keep my mind off my babies whom i havent seen 4 2 years so
          Man, that's rough! I have 7 kids and only get to see one of them (a cop in Charlotte, on the bad side) once a year or so at most. I would be pretty down not being able to see my kids all the time. I can't blame you for being upset about that.

          My stress reliever is bicycling. Nothing like a good sweat in the sunshine to help unwind, at least for me.

          like I said let it go I dont need your help. I get a bad vibration from you so im done with you good day sir.
          I didn't see earlier that you don't need my help. Sorry you get bad vibes.

          Have a good day!

          Andy
          Spektrum Development Team

          Comment

          • Xfactor
            Banned
            • Mar 2009
            • 861

            #50
            Got this in the mail today. Typically i use the good stuff at school but this was barely 20 dollars so it was worth it to not have to drive to campus everyday. Other pic is my turnigy hv 80 which im thinking of doubling so thats 160amp continuous and a 360 amp 10 second burst .The fets in a turnigy hv 80 are vishay 7164 a 60 volt 60 amp continous N fet.They have 8 of these stacked for each phase of the esc. Seems to me that they highly underate their stuff to stay safe(a good thing) if that monster 2000 is anything like this I wouldnt be afraid to run it at it maximum of 12s . The mosfets in the 12s hv 80 technically can handle 16s (60 volts). This section was directed toward randy. Personally I would feel safe running it at 12s. Ive done it already with my 80 no problems so far. Imay not mess up my turnigy to do this but I wanted you guys to get an idea of whats going on.If you want a better explanation of the (shoot thru) that andy was talking about look on microchips website and look for aplication note AN799 (matching mosfet drivers to mosfets) very helpful but let me warn you there is a little math involved nothing to bad but you need to at least know your order of operations and how to input the units correctly into you calculator. Yall didnt think id do it by hand did you? Thats what TI's are for lol.But 4 real check it out if your interested.They even have a section on hobby esc's check it out AN957.Please note that fets are case limited basic translation the fet are limited by how much heat they can take. So basically thats why we try to keep them cool. The cooler the are the more you can get out. What would a tec-cooler do? Im curious.Andy just look back to page one a read and u will see where you got off track with me over someone that calls people buckwheat. The funny thing is that actually by the rules he was supposed to recieve an infraction as well as a thread deletion but lets not go there.I personally asked steve to kill the kb thread because people are disrepectful with their disagreements. I really pray that one day this kinda stuff will stop. When i used to race it was even worse thats why I dont do it much now. Ive seen people come to blows over rc boats at the race now thats crazy so I quit racing.
            Attached Files
            Last edited by Xfactor; 05-28-2010, 01:34 PM.

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            • Xfactor
              Banned
              • Mar 2009
              • 861

              #51
              Here's one of my burned up e-aero hv 45's clear'd of it's burned mosfets; awaiting new ones. When I get the power blocks repaired I will try the double stack.
              Attached Files
              Last edited by Xfactor; 05-29-2010, 04:56 PM.

              Comment

              • Xfactor
                Banned
                • Mar 2009
                • 861

                #52
                A friend of mine damaged his 2000 monster turnigy and gave it to me to look at. My bet it got wet maybe not I forgot what he told me but the fets are VISHAY SUM110N06. I havent looked up the price yet but he needs at least 12 over half were burned. It looks to have started on the motor side of the esc. Maybe shorted or wet or loose motor wires.Heres some pics take a look.
                Attached Files
                Last edited by Xfactor; 05-30-2010, 04:29 PM.

                Comment

                • AndyKunz
                  Fast Electric Addict!
                  • Sep 2008
                  • 1437

                  #53
                  If you have that many obviously damaged, you will do much better to replace ALL in any bank that has any damaged ones. It looks like it may be been shoot-thru - are those all in a single phase? If so, you can safely replace just those in that phase (ALL in the phase) instead of all three phases.

                  Andy
                  Spektrum Development Team

                  Comment

                  • Xfactor
                    Banned
                    • Mar 2009
                    • 861

                    #54
                    Yeah they cost 4 bucks a piece. So far thats the cheapest. Of course if I ordered a 1000 yeah rite. For 24 the cost will be 102.00 just for the fets so Im talking to vishay directly to see if they will cut the cost.Maybe donate some working samples. Having to replace them all will defeat the repair I think cause you start creeping up towards the retail cost of a new one so?????I found some cheaper alternatives that I wouldnt use for my friends repair but to use in my esc design.Im slowly putting things together. Power wires,caps, microprocessor,resistors,etc. Im just so fortunate to be able to look inside of one of these .To see componenets that I know work for what were trying to do was a great learning experience. Hopefully tuesday vishay will have some good news; A free working sample

                    Comment

                    • AndyKunz
                      Fast Electric Addict!
                      • Sep 2008
                      • 1437

                      #55
                      You have to order several thousand at a time to get a reasonable price. It was the only way I could get the FET costs down on my ESCs, and yes, it was still a bundle (about $20 per ESC when buying several thousand at a time). That's normal. Try Future, Mouser, and DK to shop around. Good luck!

                      Andy
                      Spektrum Development Team

                      Comment

                      • Xfactor
                        Banned
                        • Mar 2009
                        • 861

                        #56
                        Mouser back ordered havent tried the others yet no word from vishay yet. Today I was cleaning my shop and found some suitable caps in an old car amp.5 60volt 330uf caps. A heat sink off an old 486 computer and 8 gauge wire I noticed that about the turnigy. Small wires on the motor side . They doubled the battery wires but ran singles on the a b c terminals too small in my opinion.Randy I still think you can run12s with no fear the fets and the fet driver on the 2000 goto 60 and 80 volts respectively thats 16s on the fets and 21 s on the drivers so 12 s should be safe the only thing I would say is if you can change the process speed to a higher frequency cause the more the rpms the faster the process speed needs to be. Does everyone concur?Andy?OH anyone with a 2000 id goto 8 guage motor wire if youre good at soldering.
                        Attached Files

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                        • Xfactor
                          Banned
                          • Mar 2009
                          • 861

                          #57
                          Turnigy monster 2000 cleaned and awaiting new fets and word from one of the several vendors that I have made request to.
                          Attached Files

                          Comment

                          • CornelP
                            Senior Member
                            • May 2009
                            • 745

                            #58
                            Thanks for the tip on the wiring... I'll change it once I decide if I'll use it in my next project. I already watercooled it, so it's ready... hopefully it will survive enough to get an idea about the build quality...

                            Comment

                            • Xfactor
                              Banned
                              • Mar 2009
                              • 861

                              #59
                              I didnt see any real conformal coating on the turnigy either;its an airplane esc so it needs that or some type of splash guard and a water cooling plate(brass plate with tubing soldered down both sides) . Randy has a turnigy so he could easily make an aluminum one. He has the dimensions.Water cooling will increase your load capacity.

                              Comment

                              • CornelP
                                Senior Member
                                • May 2009
                                • 745

                                #60
                                Yup, already coated in urethane, see the cooling here:
                                http://forums.offshoreelectrics.com/...t=monster+2000

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