i hope they don't put out new motors. I find it pretty annoying. We have to design new mounts and interfaces for them. Instead of improving old ones.

Just as a note though, that 60 amp breaker could do up to and sometimes over 200 amps for some period of time. It could consistantly do 120 amps easily(the matches are only 2 minutes). Thats why i was slightly worried that the new breaker would actually be tougher to use because it would be more accurate. Turns out its just good/bad. My team probably pulled about 160 consistantly this year and our breaker never tripped(our robot did... but thats different).

The three motors/side probably wouldn't trip the 120A breaker, but tripping the 60A wasn't the only issue last year. We also could easily pull the battery voltage down low enough to cause the RF link to shut down, resulting in a "lurching oscillation" when starting at full throttle in high gear. With two motors/side, this didn't happen as easily. On a few occasions, we also had "run errors" in the robot controller which might have been the result of very the high current pulls with six drive motors. Maybe some kind of automatic current limiting would be a good thing if running six drive motors and tallish gearing.

you are working on a six motor design for next year

?!

how do you know what the game is going to be next year - what the 'problem' is that your design must solve?

for all we know, there could be all new motors next year - or no motors at all!

wheels, treads, propellers..... ?!

who knows what evil schemes lurk in the minds of Dean and Woody?


:c)

For all the problems you guys were having i was extremely impressed with how well you handled it, and i was honored to be beaten by a broken bot as long as it was yous guys:)

I cant wait till we set our purdue kids loose on the idea of a switching transmission:) weee!

I love the 45 tranny's!
 

Well, after our first year with the TechnoKat modified shifter, I can only say I am impressed with the design. No failures in two regionals, and nationals, and actually almost no signs of stress in the entire drivetrain. Tons of power and tons of speed!

Next year we will take a similar design and see how far it can be shrunk and lightened and still provide this awesome robustness of the original design.

Our only problem early on was that the boxes were ever so slightly narrow that allowed the three finger dog to be in both high and low at the same time, just ever so slightly. For two weeks it worked perfectly, then one day (Just before the first ship date) we shifted and BAM locked both of them in high & low and actually the shock through the box blew the pinions off the Drill motors and bent some teeth on the 0.7 mod mating gear. What a depressing day I must say. We modified the design to use all standard gears. On the CIM was a 48tooth 0.7 Mod and 16 tooth 20 pitch 20 dpa gear cluster welded together and pressed onto the CIM. The main drive was then a 50tooth:50 tooth 20 pitch for high and a 80 tooth:20 tooth 20 pitch for low. Probably a little overkill but worked fantastic. Again Team 45 fantastic design!

Technokats and 6 motor designs
 

First, I am very proud of Andy Baker for winning the Woodie Flowers Award. He is the best thing that has ever happened to the Technokat team. I know that he has helped all of FIRST in many ways, and I salute him.

With regard to 6-motor designs:

The situation is more complicated than just how many motors you have. It depends on what you ask them to do. The gear ratio, the motor efficiency, and the applied load makes all of the difference. Properly geared and balanced with equal efficiencies, 2 or 3 motor designs would draw the same current with the same gearing and load. The main difference is in thermal capacity, which has not been a great issue over the years. The current limiters have generally prevented motor overheating issues. In short, if you can trip the breaker with two optimally set-up motors and gearing, adding a third will not help, unless it is more efficient.

Even this is oversimplified. More motors allows you to draw higher currents, and generate more torque, but can the breaker deliver any more current? And certainly traction is a great factor in using the torque. Imagine that the first year, we ran in dry, dusty field corn on plywood, and couldn't utilize 10A effectively.

another reason to use 'more' motors is redundancy.

At the Canadian regional we lost a wheel completely and [I was recently reminded] a pin in another wheels transmission was sheared

but our 4wheel drive robot still managed to drag itself up the ramp to the top, with only two motors left functional.

Re: Technokats and 6 motor designs
 

When all the motors are stalled, as in full-throttle acceleration from a standstill with "tall" gearing, more motors=more current. The higher current at or near stall with more motors is probably the main negative to use of the extra motors on a drive train. With the 120A breaker, main breaker tripping becomes a non-issue, but pulling the battery voltage down low enough to cause the control system to "act up" is still a potential problem.

I thought we HAD to use every part that was in the kit - including all the motors!

we dont?!

[just kidding]