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Unread 03-02-2014, 14:00
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Bryce2471 Bryce2471 is offline
Alumnus
AKA: Bryce Croucher
FRC #2471 (Team Mean Machine)
Team Role: Mechanical
 
Join Date: Feb 2013
Rookie Year: 2007
Location: Camas, WA
Posts: 424
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Re: pic: 2471's final winch assembly gear side

Quote:
Originally Posted by DampRobot View Post
Color me impressed. That's a really neat little assembly.

Have you done any testing to see if you can get enough torque out of the PG-71 gearbox? In the past, we've had some problems with them failing at high torque loads.

Also, could you give us a bit more info on final ratio/load/travel/windup time/current for the system?
Thanks. We haven't done any testing of the torque output yet. But the numbers say that it will be more than enough power.
The 18 volt 775 stalls at 166oz-in of torque or 10.3lb-in. After a 71:1 gear reduction that's 735lb-in. Our spool only has a 0.625" radius, so under perfect conditions it should stall producing 1180lbs of force. Multiply this by a rough torque efficiency of 0.75 and you get 880lbs.

Our shooter should take less than 200lbs to retract so the motor will be running in its happy place (about 10,000rpm) which should pull our cable at about 10in/sec. So it should get the job done in a little over 1 second. Of course it's all theoretical at this point.
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