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Motor Braking Diagram

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  • Motor Braking Diagram

    WangJ has agreed to upload the image to his webspace (my webswerver is down) and post the picture here, so hopefully we should have the image posted for all shortly

    cheers Wang, post away!
    Want your old pins collecting anywhere in the UK? email me on jezsmith@aol.com

  • #2
    Re: Motor Braking Diagram

    [img]http://pic2.****************/VOL26/934456/1718790/46612340.jpg[/img]
    [img]http://pic2.****************/VOL26/934456/1718790/39971426.jpg[/img]
    [img]http://pic2.****************/VOL26/934456/1718790/46867035.jpg[/img]
    this is not my cat
    So it goes.

    Comment


    • #3
      Re: Motor Braking Diagram

      its not just the relay that effects braking, the switch cards must close to get the remaining 50%, before the field collapses or the motor will not brake fully

      (im quite hot on this subject as i have been repairing and re-winding motors and generators for over a deccade)

      if you rely on the main winding braking alone you will get the motor slowing to a crawl and not stopping, but crawling just enough on the sweep for it to carry on past first guard and interlock the machine, this little add-on will give you 100% regen braking from the instant the sweep contactor opens.
      Want your old pins collecting anywhere in the UK? email me on jezsmith@aol.com

      Comment


      • #4
        Re: Motor Braking Diagram

        Here is the diagram as emailed to me from Jez.



        Hopefully it works!

        Comment


        • #5
          Re: Motor Braking Diagram

          hopefully it works he says :p

          i have had this set-up working for a long time!
          Want your old pins collecting anywhere in the UK? email me on jezsmith@aol.com

          Comment


          • #6
            Re: Motor Braking Diagram

            So, if I understand well, the contacts of your retrofit relay are wired parallel over the start switches.
            Will this also save the start witches(less current)?
            Where do you fit the relay and how do you wire it?
            Do you have to short both start switches or will one also work?
            (they are already connected inside the motor),
            or is it to divide the current in your retro relay?
            What kind of relay do you use?(min. current value)
            We have 220 Volts.
            Thanks for the info.
            Interesting stuff!

            Martin
            So it goes.

            Comment


            • #7
              Re: Motor Braking Diagram

              all the retro-relay actually does is aid braking, you can use it in a manner that you use one single switch card to control the relay and start-stop the motor with the relay, but this is merley to aid braking

              i actually have the relays sat ontop of the motors that were giving trouble, just connected two wires to the sweep contactor coil supply and pit a quick release plug on them, other side of the plug connected to the retrofitted relay with its contacts parralell over the switch cards, this whole seyup will only work if you use the NORMALLY CLOSED! contacts on said relay

              it works better connected to both start switch cards with 2 seperate bridges using both poles in a double pole double throw relay

              i used relays i had, rated at 10a 250v (we run 230v although at work it sits at 260 because we are 10ft from the substation)

              here is a basic run thru of how this works

              chassis applies 24v to sweep contactor, this closes the sweep contactor but OPENS the contacts on the retrofitted relay

              when 230v hits the sweep motor, the ORIGINAL START SWITCH CARDS are closed, connecting the capacitor to the motor, the motor spins up past X RPM and the centrifugal mech pops down OPENING the contacts on the switch cards and taking the starting capacitor out of circuit and the motor is then in 'run'mode

              normally when the motor stops, the sweep contactor would close its NC contacts and switch the capacitor across the main 'run' windings in the stator for regenerative braking, but this only provides about 40% of the braking effort, as the motor slows down sufficiently that the cent mech pops back up switching the starting windings into the circuit aswell, this produces the full 100% braking effort, each winding on its own will only provide 35-40% braking, when you switch the starting windings into the circuit, the starter windings are in a different, offset position thus generating AC >OUT OF PHASE< with the run windings producing what is in effect a HUGE electrical drain, similar to what happens if you get 2 phases the wrong way round when trying to syncronise 2 generators, thus braking the motor hard.

              the retrofitted relay merley makes the out of phase drain occur sooner, thus giving 100% braking from the word go, it will make the motor stop HARD

              hopefully i come across OK, its early morning, like 4am here, im knackered and am almost done scanning in the photographs from the last tractorpull event we attended
              Want your old pins collecting anywhere in the UK? email me on jezsmith@aol.com

              Comment


              • #8
                Re: Motor Braking Diagram

                Is it possible to use a 220v (coil)relay instead of a 24v relay?
                No extra wires are needed then between the chassis and motor.
                Thanks.
                So it goes.

                Comment


                • #9
                  Re: Motor Braking Diagram

                  I tried it today on the workbench.
                  One word : Amazing!!
                  Thanks for the tip, again!

                  Martin
                  So it goes.

                  Comment


                  • #10
                    Re: Motor Braking Diagram

                    told ya :p

                    works like a charm, dosent it [img]/content/btubb/images/%%GRAEMLIN_URL%%/smile.gif[/img]

                    jez
                    Want your old pins collecting anywhere in the UK? email me on jezsmith@aol.com

                    Comment


                    • #11
                      Re: Motor Braking Diagram

                      Is it possible to brake a motor *too* hard? I guess not because I figure the maximum braking force you could apply would be no more than the maximum start-up force you could apply (or does the motor now stop faster than it starts?).

                      Are the standard capacitors good enough to handle the greater current? Same with the start windings.

                      Jez, have you had them running on machines for a long time? Do you notice any difference in capacitor, winding, or gearbox life?

                      If not, then it certainly sounds like an excellent enhancement.

                      Cheers,
                      Andrew.

                      Comment


                      • #12
                        Re: Motor Braking Diagram

                        i havent had a problem for a long time so far, its a worm gear within the gearbox and the shaft only turns at 12.1 rpm so any extra stress should be neglegable

                        the capacitor gets connected to both windings as soon as the cent mech pops anyway so it shouldnt be a problem
                        Want your old pins collecting anywhere in the UK? email me on jezsmith@aol.com

                        Comment

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