Quote:
Originally Posted by Tristan Lall
They're the 00968-9015 motors, manufactured by Johnson for Fisher-Price. This year, they've got the 16-tooth gears. Last year, the same motors were provided (with 19 teeth on the pinion), and FIRST posted the specification sheet here. (See other 2008 specifications here.)
The motor pinions are 0.8 module (or possibly 32 pitch—these are virtually indistinguishable) and 20° pressure angle.
Since the F-P gearboxes fit 16-tooth motors this year, they're of a different design than the 19-tooth ones provided last year. Be careful with the COTS rules on those 19-tooth gearboxes, from 2008 and otherwise: F-P service centres stock the motors and the gearboxes together as an assembly, and won't sell them directly to FIRST teams under most circumstances. If you plan to use them, make sure that there is a vendor (in the FIRST sense of the word) for the parts. |
Has anyone tested the validity of this data? Our tests today showed a no-load speed of 19000 RPM, whereas FIRST's document states something close to 15800 RPM - we do have the 16 tooth, 9015 motors, that's for sure. We also tested with a 4.9375:1 gear reduction to make sure the extremely high speed wasn't driving the encoders crazy, and we did get the expected speed reduction (~3800 RPM).
As for the pinions, they are indeed metric: 0.8 module with a 20 degree pressure angle (while the small pinion is virtually indistinguishable from metric to Imperial, the 79-tooth mating gear is not - there's quite a bit of a difference between a 0.8 module and a 32 DP gear this size, and that's how we found out, although rather crudely
).