Thread: Determining Motor Speed?
View Single Post
  #23   Spotlight this post!  
Unread 14-02-2012, 11:37
jwakeman jwakeman is offline
Registered User
FRC #0063 (Red Barons)
Team Role: Mentor
  
Join Date: Jan 2011
Rookie Year: 2010
Location: 16510
Posts: 182
jwakeman is just really nicejwakeman is just really nicejwakeman is just really nicejwakeman is just really nicejwakeman is just really nice
Re: Determining Motor Speed?
Quote:
Originally Posted by Ether View Post
free speed of 775-12 at 12 volts is 7300 rpm. CIM-U-LATOR gear reduction is 2.7:1

7300/2.7 = 2704 rpm So you can't be using 775-12.



free speed of 775-18 at 12 volts is 13000 rpm

13000/2.7 = 4800 rpm

3600/4800 = 75%

775-18 at 12 volts at 75% speed is drawing 23 amps, and cranking out over 200 watts. And you say you have 2 of them. Something doesn't add up.
We are using two 775's (I guess the -18's) and we max out at 3200 rpm as mentioned above. We are using chain drive with sprockets. They look like 1" sprockets on the motor shafts and 6" sprockets at the wheels (I'm not sure, I just help with the software ). It takes something like 10 or 12 amps on each motor just to get the thing moving and I think it was drawing 20 or 30 amps each at full speed.