View Single Post
  #55   Spotlight this post!  
Unread 12-05-2015, 07:34
InFlight's Avatar
InFlight InFlight is offline
3574 - The King's of Bling
AKA: Jim
FRC #3574 (High Tekerz)
Team Role: Mentor
 
Join Date: Mar 2014
Rookie Year: 2012
Location: Seattle Area
Posts: 164
InFlight is an unknown quantity at this point
Re: pic: Small CIM in wheel swerve

You can skip the whole lesson on Maxwells equations and simply use the quite linear DC motor equations:

Current = ((Stall Current – Free Current) / Stall Torque) x Torque Load + Free Current

Torque Load = (Current – Free Current) x Stall Torque / (Stall Current – Free Current)

Speed = - (Free Speed / Stall Torque ) x Torque Load + Free Speed

Power = 3.14 x Speed x Torque Load / 30

The efficiency is simply power out over power in,

Eff = Power / (Current x Voltage)

For a CIM motor:
Free Speed: 5,310 rpm (+/- 10%)
Free Current: 2.7A
Maximum Power: 337 W (at 2,655 rpm, 172 oz-in, and 68A)
Stall Torque: 2.42 N-m (343.4 oz-in)
Stall Current: 133A

You run peak current at the highest torque load.

As an aside, it's no mystery why six CIM drives pop their main breakers with regularity.
__________________

Thank you 2016 Alliance Partners - 948, 1510, 2046, 2521, 2980, 2990, 4911, 4683
Reply With Quote