pic: Fisher price on steriods???????????

Oh My!, you must post some internal pics. PLEASEEEE

A bit scary (all those plastic gears) but nonetheless very interesting and quite useful in the right application.

You know what scares me more than the idea of actually managing to shove two FP motors into the same plastic gear box is that they’re wired together. Infact it looks like if you drive one the other will cause it to send a reverse current back to the other, causing it to lock up. But i’m sure you know what you’re doing. I’ll be at your pits in hartford to demistify this conundrum :smiley:

They are nylon, and most of the motors you get in the kit of parts that have worms or GB’s on them have nylon in them

We did that on our 2004 robot for our ball collector and it worked fine through three regionals, nationals, and three offseason events

Don’t you want the motors to spin opposite each other if they are meshed with the same gear?

I believe they are shorting them on purpose, looks as if they are using them as a brake?

I believe they are shorting them on purpose, looks as if they are using them as a brake?

Yes, when you “short” these motors together, they provide what is called an electrical brake, in which one is essentially a generator for electricity which “powers” the other motor, essentially causing them to turn in opposite (or the same) directions, whichever way you have them wired.

Nope. If you have two motors geared to the same gear, then there would be an odd number of gears between the motors - resulting in both motors spinning in the same direction.

I may not be the person who designed this, but the initial stages of a gearbox carry mostly speed and with little torque. As you increase the number of stages in a gearbox, more and more torque is transferred, and that is why the pitch of the gears decrease. The less teeth you have per inch, the larger the teeth get, and the more torque they can transfer.

This gearbox is going to have a lot of output power, as the two FP motors together are a little less than one-half horsepower, which is about the same as a CIM motor. (2 FP x 170 watts = 340 watts.) From this side picture, it looks like you have the auxiliary FP motor geared into the first stage from between the plastic ribs under the third stage. (The blue part is the original FP motor, and the red is the auxiliary FP motor.) Am I correct in this assumption?


that looks REALLY REALLY cool. would love to see a power curve for that bad boy

last year we burned our fp’s and the following saying was born:
ahh… nothing like the smell of fisher prices in the morning :smiley:

ahh yes…love that smoke…

neat gearbox. it’s something we wouldn’t think of. (we’d prolly spend twice the weight on a custom gearbox made out of something heavy like aluminum)

The FP’s pull cool air in front and exhaust it out the back. The original FP gearbox has two holes that go all the way through and a slot in on the back side of the gearbox to provide cooling air. Did you add the spacer between the second motor and the gearbox to allow air to get to the front of the motor?

No its just a spacer.