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DPR Chip and high RPM motors

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  • DPR Chip and high RPM motors

    Folks, can the Scaley DPR chip be upgraded to run a high RPM motor? Over say 20k RPM. I understand that they draw more amperage and that the stock DPR's cant handle it. True?

  • #2
    It's true that chips fail due to passing too much current.
    There are lots of conflicting reports about how much the motor can be upgraded before the chip fails.
    A Slot.it chip is a good upgrade for higher current motors.
    Here are some of the reasons there are conflicting reports about what rpm rating motor a chip will take.
    For similar sorts of motor, the ones with higher rpm rating usually draw more current. However, different sorts of motor with the same rpm rating can draw significantly different amounts of current.
    The power supply and track wiring make a difference to how much current the motor takes.

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    • #3
      I cannot disclose exact details on this statement, but from what I've seen chips seem to handle orange end bells running with magnets. I do believe that you can overload the system if you start pulling more amps (over 8). There is a power modification that helps by powering the unit with a wall wart on one jack and a power supply unit to vary voltage and up the amps say 10 should be plenty. I would say the orange motor under full load will use 1.2-1.5 amps and the system uses .6 so it's easy to overload. Now if you got someone who is not satisfied with the motor upgrade and say does some gut swapping with hotter than hot motors it's going to show up on that amp draw as well as on the straights and time sheets , but again I cannot get into specifics on how I know this. Some day I will publish my racing memoirs.

      Race on
      Dan
      Last edited by thumpa; 12-20-2015, 04:50 AM. Reason: Dumb$&@ who can't spell.

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      • #4
        It also depends on how much magnet the car(s) have. No magnets make for less amp draw and safer for the stock chips. Stock magnets and a orange motor are probably the limit for stock chips. Added magnets and/or hotter motors will definitely pop a Scalextric chip. If you pop a chip, get it repaired, it will be as good as a slot.it for about the same cost as replacement. OR, start with a slot.it chip.

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        • #5
          Good info all. I assume an orange motor and magless car would probably be alright. Worst case, I fry a chip and get it repaired. Rumor has it that Scalextric may release an upgraded chip later in 2016. <~~thats me fishing for confirmation

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          • #6
            I've heard the same rumor. No official word, though.

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            • #7
              a current limiter is simple to make.
              1 Nch FET
              1 NPN transistor
              and
              2 resistors (1 used to set the max current.)
              but it surprises me that this isnt part of the design of these chips.....Its possible this part of the circuitry was blown, of course, by the current spike....

              If a single car (with 4 or more lights) is pulling over 3 or 3.5A...( 8A !!?? yikes! ) somethings wrong, or its a lead sled....
              are the chips fully isolated/insulated?
              Last edited by hubcap; 01-07-2016, 06:06 PM.

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              • #8
                Heres a little schematic of a current limiter.....

                If its hard to see, clicking on the image should expand it a little bit.
                Handy little circuit to limit current to LEDs...ICs....etc etc....

                Of course one would tune the circuit for their operating voltages and LED specs.....but this is what I use to clamp Imax.

                ***EDIT*** of course if your application demands a higher current max (Imax) than let me know and I can pick the required parts you would need.
                I might even have them handy in the labs.....


                Volts (V) = Current (I) x Resistance (R)


                Last edited by hubcap; 01-08-2016, 04:46 PM.

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                • #9
                  Just a thought that came up as I think about what we have started for classes with orange endbells as the standard is that if you set the motor to be used you should say weather or not you can use a Slot it chip or the Scaley chip due to the difference in amp draw.. In real slot racing scenarios this small amp draw may be an advantage on the top end. Just saying
                  Dan

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                  • #10
                    Originally posted by hubcap View Post
                    Heres a little schematic of a current limiter.....
                    You say that's designed for LEDs and similar - looks like it would need different components to cope with the higher current draw of slot racing motors.

                    Originally posted by hubcap View Post
                    If a single car (with 4 or more lights) is pulling over 3 or 3.5A...( 8A !!?? yikes! ) somethings wrong, or its a lead sled....
                    For digital racing I guess few would want to motors taking over 3 or 3.5A.
                    The fastest 1/32 cars do take way over 8 amps, and modern chassis are pretty light. As far as I know, those aren't raced in digital.

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                    • #11
                      Originally posted by Al's slotracing View Post
                      You say that's designed for LEDs and similar - looks like it would need different components to cope with the higher current draw of slot racing motors.
                      its mainly what I use to limit current to LEDs. I tend to use beefier LEDs than is required because thats what I have available to me on my bench. (3Vf and Imax of 800mA) As noted in the pic, the circuit can be tailor-made to your requirements, obviously changing the specs of the components involved to your application......at least I thought I mentioned that......
                      Motors and other higher 'current demanders,' of course, would need to be tailor fit....and of course have the Imax raised. In this application to double the Imax, half the value of R2. (=600mA out) Larger current caps need other components but the basic idea remains.

                      Something like this circuit could be handy to protect sensitive things (like chips) by setting the Imax to the chip itself. It would be placed between contacts and chip set to cap the current just under the design specifications. Safe way to avoid mishaps and the circuit takes up about a square .250 x .250. Even smaller for the experienced.
                      This circuit is also good for LED/lighting intensive layouts. You can organize lighting by "zone" and control the flow to each "zone" making organizing current draws much easier, and making a more professional and organized layout overall.




                      Originally posted by Al's slotracing View Post
                      For digital racing I guess few would want to motors taking over 3 or 3.5A.
                      The fastest 1/32 cars do take way over 8 amps, and modern chassis are pretty light. As far as I know, those aren't raced in digital.
                      8 amps! why?
                      Do those 20k+ rpm motors really draw (require) THAT much? How much draw do those chips take (in the context of digital cars)? What do (should) the lights draw? 4 lights....maybe an amp. maybe.....(most likely there is a similar circuit to what I posted on the chip that limits the current to the lights from the PCB, anyways.....I just need to buy one and tear it apart on my bench.)

                      Those newer motors draw THAT much current? PER car?
                      Or are we talking a maxed out setup? (8A+ draw per lane, with 4-6cars? Sure. I can see that.....) Im not a dc motor pro but some of our products have mabuchi motors in them.......granted only up to 12k rpm but they only draw about 1.75A. I cant logically justify quadruple the draw for double the output....
                      what am I missing?

                      I dont want to be giving bum scoop here.....



                      -Hubcap
                      Last edited by hubcap; 01-08-2016, 08:25 PM.

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                      • #12
                        hi Hubcap, welcome to the monkey house. There are many more knowledgeable players out there than me, but here's a couple of thoughts.

                        Yes there are motors that draw over eight amps, but they used in a different type of slot car racing; they tend to be expensive, short lived and powerful enough to be almost undrivable on most digital layouts.

                        Unless you're running a really really hi amp motor, the digital board doesn't burn out instantly when a motor that requires higher power than a stock Scalex motor is used. Rather the life of some critical component on the board will be shortened by an amount proportional to the amount of power over the specified design limit for that component that is run through it (i.e. the weakest link, I think I read somewhere it's one of the caps). Also the life to power relationship is non-linear, the more over the design limit you go the shorter the life of the component, by the square or cube or some such of the amount you're over.

                        Peak power draw for slot car motors is at stall, i.e. getting the car moving from a standing start, and drop quickly from there. A stock Scalex motor draws something like 2 amps at dead stall (zero rpm) but less than half an amp at normal track speeds. Slot.it orange end bell motors and their equivalent draw in the 3 to 3.5 amp range at stall.

                        As was mentioned in previous posts anything that adds drag (magnets, weight, crappy bearings) raises the power needed to move the car. Raise the power requirement above the design limit of the critical component and you start shortening the life of the board.

                        The power draw of the LED lights in a slotcar is negligible compared to the power taken by the motor. Some people race with them installed, others remove them; it appears to have no noticeable effect.

                        cheers
                        Scott

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                        • #13
                          Originally posted by hubcap View Post
                          8 amps! why?
                          Do those 20k+ rpm motors really draw (require) THAT much? How much draw do those chips take (in the context of digital cars)? .............
                          Those newer motors draw THAT much current? PER car?
                          Or are we talking a maxed out setup? (8A+ draw per lane, with 4-6cars? Sure. I can see that.....) .......
                          Yes, well over 8 amps per car.
                          Why? To produce more power which makes the car go faster in a straight line, which makes for faster lap times if the rest of the car and the driver are up to it.
                          As I mentioned in my previous post, as far as I know, those higher current motors aren't raced in digital. There is no chip in the car. As far as I know there are no digital chips on the market that are suitable for higher current motors.
                          Last edited by Al's slotracing; 01-09-2016, 12:54 AM.

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                          • #14
                            Originally posted by Al's slotracing View Post
                            Yes, well over 8 amps per car.
                            Why? To produce more power which makes the car go faster in a straight line....
                            Obviously.



                            Originally posted by Al's slotracing View Post
                            ....which makes for faster lap times if the rest of the car and the driver are up to it.
                            Obviously.

                            Im still learning how these digital tracks function, so, there will be some stupid questions along the way, but, c'mon maaaaaan. A 5 year old can understand more draw on a dc motor....more spin. hahaha

                            I'm thinking analytically........and not "weekend competition-ly," if you will.
                            I can see where competition would cause people to take this route, but, the major gainers are your local utility and the people that make these motors. From an efficacy standpoint....its wasteful. You are quadrupling draw to double output.



                            Anyway.....a simple current limiter that one can tune to their application if one requires a "safety" or a "cap" on their current draw designs.

                            -Hubcap

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                            • #15
                              Originally posted by hubcap View Post
                              I can see where competition would cause people to take this route, but, the major gainers are your local utility and the people that make these motors. From an efficacy standpoint....its wasteful. You are quadrupling draw to double output.
                              The major gainers are the racers who enjoy racing faster slot cars.
                              For sure not everybody wants to race the faster cars. There's plenty of racing available for those who prefer something less quick.
                              Surely it's good that there are manufacturers that supply the very wide range of slot racing products racers want to race.
                              The local utility companies aren't going to get rich on the pretty small amount of extra power the more powerful motors take - for sure far more energy in consumed it heating and lighting the club room.

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