Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: cooldog on November 30, 2007, 09:14:30 PM

Title: are these good motors
Post by: cooldog on November 30, 2007, 09:14:30 PM: i did the motor calculations and got this

RMF-87.4 lb*ft*rps
momentum-100 lb*ft / s
motor rotaion speed-0.318 rps

then i found this motor and got these specs
http://cgi.ebay.ca/One-DC-12V-12-V-DC-30RPM-High-Torque-Gear-Motor-BuySAFE_W0QQitemZ280176954148QQihZ018QQcategoryZ71400QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

torque- 264 lb*ft
speed-30 rpm
motor rmf-132

also i checked the parts list but i am having problems finding 0.5ft foam wheels with a 4.00mm hole
or will i need smaller shaft hole so my motor goes in snuggly.

also a motor controller that is cheap, easy to connect and that i can hook to my r/c receiver.
i found this one i like it because it is very easy to use and plugs dirctly to my reciver
http://www.dimensionengineering.com/Sabertooth2X5RC.htm

will this motor or motor controller be over kill

PS. i am planning on studying human interaction with life size robots
Title: Re: are these good motors
Post by: Admin on December 01, 2007, 09:22:50 AM: Quote
also i checked the parts list but i am having problems finding 0.5ft foam wheels with a 4.00mm hole
or will i need smaller shaft hole so my motor goes in snuggly.
If you can't find one, remember you can always drill the hole to be bigger. For small robots you can do whats called a press fit, which basically means use force to jam the wheel tight onto the motor output shaft. But for larger robots (like yours) you should use a wheel hub. You attach the hub to your wheel using screws, and your motor shaft goes into the hub.

Quote
will this motor or motor controller be over kill
find out how much current your motor will draw (the ebay site doesn't list it)
I thinking your motor controller selection won't be enough.
This guy might be better:
http://www.dimensionengineering.com/Sabertooth2X10.htm
Title: Re: are these good motors
Post by: cooldog on December 01, 2007, 12:35:11 PM: how do i find out how much my motors draw
Title: Re: are these good motors
Post by: Steve Joblin on December 01, 2007, 12:42:54 PM: connect a power supply to it, then use a DMM. Make sure to measure the draw during no-load (the motor running freely), under load, and the stall current (when you prevent the motor from turning)
Title: Re: are these good motors
Post by: cooldog on December 01, 2007, 12:44:33 PM: okay but i don't want to buy the motors and findout they are the wrong kind
Title: Re: are these good motors
Post by: Admin on December 01, 2007, 01:14:41 PM: check the datasheets!
Title: Re: are these good motors
Post by: cooldog on December 07, 2007, 08:15:17 PM: okay thanks guys i have another topic but in decided to go into this one

i need your oppinion on the Solarbotics GM9 90 Degree Shaft Gearmotor with wheels
http://www.pololu.com/products/solbot/0188/

i need a personal opinion on there speed and torque if any one has used them. i know to check what the gears are but i want a personal opinion.

i am planning on making a nock off off this

http://www.superdroidrobots.com/pictures/ATR/Deluxe.jpg