can motors be modified

[ronnie_82]

i'm with a first year team and wondering if motors can be modified? what are some situations your team may ran into your first year?thanks ronnie_82

[rbayer]

By modify, do you mean taking them apart and rewinding, etc? FIRST generally says no to modifying anything involving electricity or pneumatics, but I haven't ever heard this issue addressed specifically, so maybe it's OK.

[ronnie_82]

Thanks for that information. I will look into it further

[Adam Y.]

No. You can't rewire them at least as far as I can tell.

[ChrisH]

In previous years motor modifications have been specifically prohibited. The output shaft of the motor assembly may be modified.

To give an example: We used to get "window" motors. These motors had a worm gear built into the case that then turned still another gear that was the output. It would be legal to modify the output gear by putting a hole in it or otherwise changing it so it could be adapted to drive whatever you were trying to drive.

But changes to the worm gear or the motor itself were not permitted.

As a general rule we modify the motors, including the output shafts, as little as possible. That way if we fry one during a competition we can replace it more easily. It can be really hard to put a keyway into a the shaft of a new motor in the Pits at a Regional. If you absolutely must modify a motor, always buy a spare and modify that one too in the same way, and check to make sure it works as intended. Doing so will save much embarasment at the very least.

Besides the stuff you have spares for never breaks

[Adam Y.]

Wooohoo I answered a question correctly.

[Bduggan04]

I'm pretty sure you can cut holes in the front of the housing for cooling. I've seen teams that have done it, and I'm pretty sure there are no rules against it.

[ChrisH]

Originally posted by Bduggan04
I'm pretty sure you can cut holes in the front of the housing for cooling. I've seen teams that have done it, and I'm pretty sure there are no rules against it.

As a "strict constructionist" I would say that was indeed a violation of the rules. Unless there was a specific mention of this modification in the documentation, and I don't recall any off hand.

The thermal capacity of the motors is one of the constraints we have to live with. It is however, perfectly legal to use fancy aluminum extrusions for a heatsink and incorporate them into your mount.

Just because somebody got away with it doesn't mean was legal.

[Andy A.]

Taken from the 2002 manul:

M17. The motors in the kit may not be modified except as follows:
• It is acceptable to modify the mounting brackets and/or other structural parts of
the motors (output shaft, housing, etc.) as long as the electrical system is not
modified and the integral mechanical system of the moving parts (bearings,
bushings, worm gear output stages, etc.) is not changed or removed.
• The gearboxes for the Fisher-Price, Drill, and Globe motors are not considered
“integral” and may be separated from the motors. FIRST will not provide
replacement for parts that fail due to modification.

The way I read it, it is legal to drill holes in the motor. However, I think that the extra cooling it might provide is offset by the chance of damaging the motor, either while drilling or when crap gets in it. Stick with heatsinks to avoid any problems. They look cooler anyways.

Also, be aware that these are 2002 rules, and are subject to change in Janurary.

-Andy A.

[Bduggan04]

While heat sinks are a good idea, the metal band around the drill motor makes them less effective. However, the band is necessary for the motor to be most efficient. It's best to reduce the load on the motors, or use an electrical system to monitor the current load and prevent back driving. Either way it reduces the heat of the motor and the likeliness to trip the breaker.

[Al Skierkiewicz]

How were you able to modify the cases to get more air flow without having metal shavings caught down inside the magnet structure?

[AJ Quick]

How would they check?

What is stopping someone from putting a better motor in the drill motor's casing?

[Bill Gold]

Originally posted by AJ Quick
How would they check?

What is stopping someone from putting a better motor in the drill motor's casing?

Pride. Honesty. Wanting to abide by the rules to try to keep a fair playing field. Those reasons, and I'm sure many more, are what stops people from using illegal motors (model and/or quantity).

[Ken Leung]

Originally posted by AJ Quick
How would they check?

What is stopping someone from putting a better motor in the drill motor's casing?

Nothing at all, except something call "gracious professionalism". .

If you are absolutely certain you want to do something against the rules that will give you unfair advantages over other teams, there's no way for FIRST to stop you.

If you happen to win the competition because of that unfair advantage, would you really be proud when you know you cheated others out of a fair chance to compete for the champion? If so, then I would say you learned absolutely nothing valuable from this competition.

But of course you won't be doing that, right?

[Bduggan04]

Originally posted by Al Skierkiewicz
How were you able to modify the cases to get more air flow without having metal shavings caught down inside the magnet structure?

Like I said earlier, I only saw it done. I'm not sure how you could do it, possibly disassembling the case from the rest of the motor and then machining it. Maybe they used another magnet to lift the shavings away from it, I'm not really sure. Previous year's motors might have been used as practice.