Engine braking

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    • January 15, 2003 at 8:20 pm #10062
      Crom
      Participant
      • Posts: 143

      Hi again,

      Does it seem like the bcg stops really really fast when you let off of forward or reverse? I know that bits are really small and don’t have a lot of momentum, but doesn’t it seem like the wheels stop turning really quickly?

      I was wondering if the motor was shorted when not pressing forward or reverse, which would make the motor stop really quickly…

      Does anyone have schematics of the Bit electronics in the car so I can be sure?

    • January 16, 2003 at 3:55 am #43249
      micro_Amps
      Participant
      • Posts: 1290

      As far as I know the armature of the motor is not shorted when forward or reverse is let released. If it was the wheels would lock and skid when you let the button go. The reason I say this is I saw a mod on a site somewhere that puts ‘engine braking’ on when you let go. The reason it stops so quickly is because of the high gearing. I wouldnt worry about fitting the mod, I cant see it adding to handling, performance or enjoyment for that matter
      uA

    • January 16, 2003 at 4:00 am #43247
      micro_Amps
      Participant
      • Posts: 1290

      Isnt this supposed to be in the techo section :smiley2:

    • January 16, 2003 at 5:07 am #43235
      jamiekulhanek
      Participant
      • Posts: 2563

      When KIT racer gears are used, the braking performance is greatly reduced. The 12:1 BCG gears give the best braking.

    • January 16, 2003 at 1:26 pm #43225
      Admin
      Participant
      • Posts: 5952

      hum..y do yall want quick breaking…i hate it..i want me to slow down nice and gently…does any1 kno how to do this?

    • January 16, 2003 at 5:38 pm #43209
      Admin
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      • Posts: 5952
      Quote:
      I was wondering if the motor was shorted when not pressing forward or reverse, which would make the motor stop really quickly…

      The motor is definately not shorted.
      A couple of my char-g’s free wheel a bit better than the other’s.
      It can depend on how freely the gears rotate.

      http://www.users.bigpond.com/sandrashane/char-g/compact.html

    • January 16, 2003 at 6:18 pm #43207
      Cranga
      Participant
      • Posts: 180

      It is fun though, cause its like doing a handbreak turn, if you have enough power!:smiley16:

      Round and round not up and down

    • January 16, 2003 at 6:36 pm #43204
      Crom
      Participant
      • Posts: 143
      Quote:
      The motor is definately not shorted.
      A couple of my char-g’s free wheel a bit better than the other’s.
      It can depend on how freely the gears rotate.

      Oh, so I guess its just because my stock gear doesn’t free wheel very well…

      Thanks!

    • January 16, 2003 at 6:40 pm #43203
      Crom
      Participant
      • Posts: 143
      Quote:
      Isnt this supposed to be in the techo section :smiley2:

      Oops… hehehhe:D

    • January 17, 2003 at 6:50 am #43132
      GT-ahh
      Participant
      • Posts: 774

      the motor will create a back emf when its rolling tho…this creates abit of breaking power via eddy currents..

      http://gtahh.web1000.com/
      custom shells, mods and tips

    • January 17, 2003 at 8:35 pm #43098
      Crom
      Participant
      • Posts: 143

      Back emf… hrmm…

      Depending on the actual circuitry of the car… Rolling the car backwards for a very very looonng time when it is discharged could recharge the battery? 😀

      Heheh, just kidding… :smiley2:

      The impossible just takes a little longer

    • January 17, 2003 at 9:05 pm #43095
      micro_Amps
      Participant
      • Posts: 1290

      Sorry to rain on your parade but it wouldnt charge, because the drive transistors (even if turned on) wont conduct on reverse polarity.
      If the motor was directly wired to the battery it would tho, but then you would have no start/stop control when the battery is full.
      The back emf will only ‘brake’ the motor if it is shorted accross a resistance. When you let ‘forward’ go, the time that the motor takes to slow down really depends on what gear set you have in and how much friction is in the drive train.
      Sorry, I just cant resist these techo issues:dead:
      even if they are in the wrong section:shock:

    • January 17, 2003 at 9:10 pm #43093
      Crom
      Participant
      • Posts: 143
      Quote:
      Sorry to rain on your parade but it wouldnt charge, because the drive transistors (even if turned on) wont conduct on reverse polarity.
      If the motor was directly wired to the battery it would tho, but then you would have no start/stop control when the battery is full.
      The back emf will only ‘brake’ the motor if it is shorted accross a resistance. When you let ‘forward’ go, the time that the motor takes to slow down really depends on what gear set you have in and how much friction is in the drive train.
      Sorry, I just cant resist these techo issues:dead:
      even if they are in the wrong section:shock:

      I know I know… I was just fooling…

      hrmm… can the topic be moved to BCG Technical? Although I think its pretty dead now…

      The impossible just takes a little longer

    • January 20, 2003 at 6:02 pm #42965
      z-beam
      Participant
      • Posts: 2265

      the standard bcg pinion gear has 6 spokes
      a kit racers got 7
      but my oem special ed.loctite zexel’s got 8 spokes
      i’ve had to cut at my bcg’s so that any pinion can be used. i also use flat tipped screws to balance the angle of the motor. this is how to tune gears to be loose (no brakes) or tight (hand brake). can you buy the 8spoke special ed gear sets?

    • January 20, 2003 at 6:17 pm #42963
      Cranga
      Participant
      • Posts: 180

      Hmm, I think it could be because of the motor, i have a BCG with a 3.0 and a BCG with some crazy nano racer motor in it, when you stop with the 3.0 it instantly stops and with the nano racer it rolls for a little bit, even when stopping on a hill (on my track) the car rolls back.

      Bap Bap Bap

    • January 22, 2003 at 6:33 pm #42763
      Crom
      Participant
      • Posts: 143
      Quote:
      the standard bcg pinion gear has 6 spokes
      a kit racers got 7
      but my oem special ed.loctite zexel’s got 8 spokes
      i’ve had to cut at my bcg’s so that any pinion can be used. i also use flat tipped screws to balance the angle of the motor. this is how to tune gears to be loose (no brakes) or tight (hand brake). can you buy the 8spoke special ed gear sets?

      Ehhh… I”m not really brave enough to do a lot of modding on my bit so I’m not even going to try and tune my gears like you’ve described. Haven’t even heard of 8 spoke gears…

      On the other hand, I bought a KIT racer last night for the motor and batt. The 2.6 rolls after I release the gas, so I guess it just comes down to the characteristics of motor. And not due to a design thing.

      The impossible just takes a little longer

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