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Unread 25-08-2016, 18:06
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Re: Versaplanetary Output Direction

Quote:
Originally Posted by Max Boord View Post
Correct. it is also worth noting that the 10:1 carrier plate fails at 100 N-M while a stalled 775pro with a 100:1 reduction will develop only 71 N-M at stall neglecting the inefficiencies of the stages needed to develop the 100:1 reduction. in other words, unless you use the dual input stage or use a motor and gearbox combination not recommended by vexpro it should not be possible to develop the torque necessary to break the ring gear on a VP.

Also as someone who managed to accidentally stall a 775pro into a 100 to 1 versa (10:1 and 10:1) this season, I can attest that the 775pro will fail before the versa will.
You're able to develop more than the stall torque in FRC in two likely cases;

1) Reversing the voltage of the motor while still travling the other direction, this will results in a larger voltage across the motor than 12V, and generate higher torques (it stops being linear after the magnets saturate, unsure when that point is).

2) Dynamic and shock loads can cause brief torque spikes above the stall torque of the motor.

Unfortunately the above two make system sizing to avoid failure a little trickier, and for those reasons I would want to stay a good deal inside the Vexpro published ratings for the versaplanetaries to guarantee they keep running smoothly.

Voltage ramping (limiting the instantaneous rate of change of the speed controller output) can help alleviate the above two, but at the cost of acceleration time (likely negligible in most designs).

That being said, 330 has run them in quite large (but within spec) reductions the last two seasons on nearly all their systems with good success. I'm unsure if they do any voltage ramping or other tricks.
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