View Single Post
  #6   Spotlight this post!  
Unread 05-08-2007, 14:40
Greg Needel's Avatar Unsung FIRST Hero
Greg Needel Greg Needel is offline
REVving up for a new season
FRC #2848 (All-sparks)
Team Role: Engineer
 
Join Date: Jan 2002
Rookie Year: 2002
Location: Dallas, TX
Posts: 3,110
Greg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond repute
Re: Plantery Gearbox Efficiency

Quote:
Originally Posted by AdamHeard View Post
I may be way off here..... but I think i'm quoting Dr. Joe Johnson here...

A planetary stage is about 85% efficient, so .85^2~ 72.

90% overall seems kind of fishy to me since that is the efficiency of a single spur gear reduction.

I would agree but spur gears are 90%~95% efficient if designed correctly. and with 2 stages in this transmission that puts the efficiency at 81-90%. This is using the standard method of multiplying the number of stages by the efficiency . But in a planetary since there are much points of contact per stage it is not entirely accurate.

now knowing the history of these transmissions and how poorly they are crafted and not taking into account the multiple contact points per stage I would suspect it would be at the bottom of that range close to 80%.

what we really need is for someone to take a cim motor and create a testing torque curve. Then mount that same cim motor in the tranny and test it again. We can then find out the true looses in the system.

Anyone got a torque cell lying around?
__________________
Greg Needel│www.robogreg.com
Co-founder REV Robotics LLC www.REVrobotics.com
2014 FRC World Champions with 254, 469, & 74