Adjustable Voltage

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  • #14941
    porsche917porsche917
    Moderator

    Adjustable Voltage

     

    Issues

    ·        Purchasing multiple motors to find one “magic” motor

    ·        Having to purchase multiple gears to find the right one for the car and voltage mix

    ·        Limited by low gears in some series   

     

    Details

    The issue with many if not all of our series is developing a set of rules that make racing as fair as possible while allowing the skilled racers or car builders to excel.  A typical set of rules would do this by setting limits on motors, gearing, wheels, tires.  All of this is done with a stated voltage for the series.  

     

    In the past these rules have accomplished their goal of keeping the cars closely matched while providing some great on track battles.  Having said that, members driving skills, their ability to set up cars, the track’s grip and care and maintenance of tires have all improved.

     

    All of this means is that some racers have maxed out the available gearing to where the quality of the motor now plays a larger role in the final results.  This leads to racers spending more money on motors hoping to find the one “magic” one that has a slightly higher RPM rating at a given voltage.  

     

    For example, let’s take the clubs most popular series – the Slot It Group C series.  The rules regarding motors have everyone running the same Slot It MX16 V12 motor rated at 23K rpm (@12volts) and the voltage for the series at 11volts.  Just these two rules have the majority of the racers running the lowest possible gearing available from Slot It* – 9t pinion with a 23t crown or a 2.56 gear ratio. 

    *It’s possible to run a 10t pinion to get a lower gear ration but the gear mesh between a 10t pinion and a 23 or greater crown is poor and causes its own issues in terms of braking and motor wear.

     

    Proposed Solution #1 – Adjustable Voltage

    If each racer at each drivers station was allowed to set their own voltage for that specific race they would not have to spend so much time trying to find the “god” motor or the perfect gearing as they could adjust the voltage to their car with its motor and gearing on the specific lane you are running and with the level of skill you were bringing to the track on that day.  Image having a boost knob you could turn up to give you more power.

     

    Proposed Solution #2 – Raise the Voltage

    Raise the voltage for all series to a minimum of 12v so there is some room for racers to have a wider range of gears to choose from to get the performance of their car where they want it.

     

    Raising the voltage of the Slot It Group C series to 12v would have the effect of increasing the RPM of the rear wheels by a little under 11%.  This would be enough for some of the fast guys to move to a 24t or 25t crown and give them the ability to run a 23t if they were really on top of their game.

     

    Please use the forum to post all of your comments and concerns.

     

    #14946
    DattoDatto
    Participant

    I have no objection. I use a diode rotary switch for my little 1/43 hillclimb, but that may not be precise enough for the club.

    Rotary switch

    Driver-Station

    "Enjoy every sandwich"
    -Warren Zevon

    Attachments:
    #14948
    chapracer65chapracer65
    Participant

    I would think that some experimentation would be required on this topic.  It will be simple enough to try running various cars at different voltages (using the voltage adjustment on the Pyramid power supply) and comparing lap times versus drivability.  This will take some work.  Say with a Group C car, try it at 12 volts and see how it runs.  Is it faster?  Is it faster but much twitchier?  Put a numerically taller gear in it and see if you can get a faster lap speed than the baseline but still have it drivable.  Try it at 13 volts and test it some more.  I think we will need time to have everyone do this experimentation.  It looks like adjusting the voltage could be an easy fix to help a car with a weak motor but it might make setup more complicated because it could also work with a “normal” or “hot” motor but require different gearing, which would raise the bar and the “weak” motor would be outclassed once again.  If this is the case, we could  require a specific gear and let everyone choose their voltage.

    For this testing we may need to wait until safer track access is available.  It sounds like Ary’s voltage regulators would cost $30 plus for each lane, plus the time to install them.  With club dues now due once again, and the possibility that some members may be short on money, I don’t think we should spend the money for the regulators right now.  Except for the cost and labor I do not see a down side for installing the regulators, whether we use them, or limit their use, or not.  It does give us more options.

    #14949
    DattoDatto
    Participant

    What is the proposed interface design for the voltage adjustment at each driver station?

    "Enjoy every sandwich"
    -Warren Zevon

    #14950
    chapracer65chapracer65
    Participant

    There will be an LED readout at each station.  Ary demonstrated at last video conference.  the assembly was 3 or 4 inches square, a couple of inches tall.

    #14951
    DattoDatto
    Participant

    Video conference?

    "Enjoy every sandwich"
    -Warren Zevon

    #14952
    porsche917porsche917
    Moderator

    Marc – I just sent you an email with the meeting invite.

    #14953
    porsche917porsche917
    Moderator

    I agree with Russell that we should test this out first and that it is not a top priority at the moment when we are not even running.  I also think this option adds another large variable to the car set up.  I don’t think it would be too difficult to figure out but it does add another layer to the set up (complication) of any car you would run.  It would mean that you would need to spend more time running each lane prior to a race to figure out exactly what voltage works best for your car on that lane on that day.  The reason I say “that day” is because many have already experienced issues with setting up a car on Thursday night only to realize the car does not work the same way on Saturday when the races are held.

    As much as I am intrigued about the concept I would also would like, as I stated on our Saturday call, a switch that puts the voltage at all drivers stations the same.  This would allow us to quickly put everyone back on the same footing if we decided we needed to for a race or series.

    I

    #14954
    Radial TARadial TA
    Participant

    since I have been running by myself and setting the voltage as I decide, I found I can run the Revo and Thunder at 11 volts and not de-slot.  Important when I don’t have a few marshals.  But the lap times are slower by 3 – 4 tenths.  We have been setting the 12 volt races on the edge of control for me.

    #14955
    BarkingSpyderBarkingSpyder
    Participant

    I know costs are tight, but if we move in this direction, I suggest we replace the Pyramid with a better power supply. Digitial, max of 20 or 30 volts, 10amps. This may prevent ‘drops’ we typically experience when everyone is on, and then the surge when two people de-slot.

    "Come On! Lets go space trucking!" Deep Purple

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