Battery Buggy B

[Dark Sabre]

Hi. Our school had two teams. On the other team, the Battery Buggy kind of "failed". The motor melted, and it uses up the batteries in literally 2 runs. Do you guys have any ideas?

If the motor is "melting" I assume that what's happening is that the coating on the windings (the wraps of wire inside the motor) is burning off and smoking.
There's plenty of ways to drain batteries quickly, like not having enough in parallel for the motor, just running the motor too hard, whatever.

There's two reasons I can think of right now that your motor might be "melting":

• Stalling the motor (if you have the motor hooked to batteries, but the motor can't turn, the energy has to go somewhere and the windings get really hot and the enamel coating vaporizes. As you stall a motor, its current consumption skyrockets. If you were continually stalling a motor, you could be both draining batteries really quickly and "melting" the motor.
• Using too high of a voltage for the motor. If you have a working motor...smell it when it has not been run for a while. Shouldn't smell like anything. If you turn the motor on and it is freely rotating and starts smelling like burning electrical stuff, you are probably using too high of a voltage for the motor. Using the motor with too high of a voltage for a while could definitely damage the windings. That could probably cause shorts that would drain the batteries faster.

You can probably double check the motor's rated voltage vs what you are using pretty easily, so if you are using way too high of a voltage...don't.

You could be stalling the motor in all sorts of ways, like...

• If you are using like a wingnut braking system, but it only jams the axle instead of also turning the motor off, that is stalling the motor
• If you are using too large of a gear ratio (or pulleys in your case, though the pulleys would probably just slip instead of the motor stalling, so this probably isn't the case for you), the motor might be unable to turn the system. This would be mostly a problem at the starting line when you are coming from rest, so if the vehicle is moving, this probably isn't the problem.

So if your motor is being powered, but it isn't turning, that's going to be bad for both the battery and the motor.

If none of that sounds like what you might be having trouble with, could you elaborate on:
What exactly is happening to the motor when you say "melting": does it smoke? does it smell? does it still run afterwards? is it really hot while running?
What kind of braking system are you using? Is the motor ever being stalled?
If you know, where is the motor from and what is it rated for voltage/current-wise?
What kind of batteries are you using? How many and in what arrangement?
Stuff like that...

[kahafman]

we got a new motor, lets see what happens. Also, they ran it for hours for 3 consecutive days, FYI

[StampingKid]

Is there a trick to perfect alignment/ Our frame is absolutely square. Axle holes were drilled in pairs with drill press. We have bearings on the axles. But we still get right hand drift. We are on second set of axles as toeing in did not correct it. Even tried running on three wheels.

[Balsa Man]

Is there a trick to perfect alignment/ Our frame is absolutely square. Axle holes were drilled in pairs with drill press. We have bearings on the axles. But we still get right hand drift. We are on second set of axles as toeing in did not correct it. Even tried running on three wheels.

Check wheel size/diameter. It doesn't take much difference in left/right diameter to get a drift off of straight. Match wheel sizes on each axle as accurately as you possibly can (doesn't matter if front/rear are different - left and right have to be the same).

[StampingKid]

That may explain as I am using lite flites. I will put a gauge on them. Would like to use cd wheels as they are absolutely uniform but get an almost immediate right hand turn as they cannot grip enough even with rubber covers to overcome the friction caused by the threaded rod.

[Balsa Man]

That may explain as I am using lite flites. I will put a gauge on them. Would like to use cd wheels as they are absolutely uniform but get an almost immediate right hand turn as they cannot grip enough even with rubber covers to overcome the friction caused by the threaded rod.

If you do see a difference, the trick is to get them both on a shaft, put it in a drill press or lathe, use file or sandpaper to match them exactly, put 'em back on the vehicle. Last year on Electric Vehicle, that took us from a 10cm drift/turn to < a cm......

Depending on the gauge you have, you may or may not see a difference. If you take each one, make a little, precise mark at the circumference, put that mark at a mark on the ground, roll it 3 or 4, or 5, or... revolutions and carefully mark where that circumference mark hits ground, then do it with the other one, they should come out to the same place. A way to get a 3.14... x improvement in resolution over measuring diameter.

[computergeek3]

Can anyone tell me how to make a buggy go straight if it is currently veering off to the left. It has front-wheel drive, and the gears are more towards the right of the vehicle.

[cooltiger]

Can anyone tell me how to make a buggy go straight if it is currently veering off to the left. It has front-wheel drive, and the gears are more towards the right of the vehicle.

Their are several reasons why this might happen, their may be too much weight on one side or a wheel may be loose. You can try and add some weight to the oppisite side to sway it in that direction, you can lubricate the axel for less friction so it will make it run smooter. If you run out of time, you can aim it so that it will stay on the center line.

[omar565]

guys i deceided to use the wingnut system and when my buggy moves the wingnut doesn't, does anybody know why this is happenening? Do i need to put a restraining rod?

[robotman]

guys i deceided to use the wingnut system and when my buggy moves the wingnut doesn't, does anybody know why this is happenening? Do i need to put a restraining rod?

yes if it doesn't move you should add a rod
The rod should make the wing nut more in a certain track and also allow for more accurate stops