Engineering

Reference

Motor database

Published 12 V specs for common FRC motors. Calculators that ask for a motor use these numbers.

MotorVendorFree speed (rpm)Stall torque (N·m)Stall current (A)Free current (A)Peak power (W)kT, WPILib (N·m/A)
WCP6,0007.0936621,1100.0194
WCP5,8009.3748321,4200.0194
WCP7,7584.1127938350.0147
WCP7,3685.0132939660.0152
CTRE / VEX6,3804.692571.57830.0182
CTRE / VEX6,0805.843041.59300.0192
REV6,7843.62113.66390.0171
REV5,6762.61051.83860.0248
REV11,0000.971001.42790.0097
VEX5,3302.411312.73360.0184
VEX5,8401.418932160.0158
VEX18,7300.711340.73480.0053
VEX13,1800.43531.81480.00811

Specs change with firmware and commutation mode (FOC rows use CTRE’s Field Oriented Control), so check the vendor’s current data sheet before relying on a number. Peak power is at half stall torque. kT is stall torque ÷ stall current, as WPILib’s DCMotor defines it.

Kraken X60 curves at 12 V

Speed
Speed: Speed against Torque. The data table below lists the values.01,0002,0003,0004,0005,0006,00001234567Torque (N·m)Speed (rpm)
Data table
Torque (N·m)Speed (rpm)
06,000
0.62045,475
1.2414,950
1.8614,425
2.4813,900
3.1023,375
3.7222,850
4.3432,325
4.9631,800
5.5831,275
6.204750
6.824225
7.09−1.332 × 10^−12
Current
Current: Current against Torque. The data table below lists the values.05010015020025030035040001234567Torque (N·m)Current (A)
Data table
Torque (N·m)Current (A)
02
0.620433.85
1.24165.7
1.86197.55
2.481129.4
3.102161.3
3.722193.1
4.343225
4.963256.8
5.583288.7
6.204320.5
6.824352.3
7.09366
Output power
Output power: Power against Torque. The data table below lists the values.02004006008001,0001,20001234567Torque (N·m)Power (W)
Data table
Torque (N·m)Power (W)
00
0.6204355.7
1.241643.2
1.861862.4
2.4811,013
3.1021,096
3.7221,111
4.3431,057
4.963935.5
5.583745.5
6.204487.2
6.824160.8
7.09−9.892 × 10^−13
Efficiency
Efficiency: Efficiency against Torque. The data table below lists the values.02040608010001234567Torque (N·m)Efficiency (%)
Data table
Torque (N·m)Efficiency (%)
00
0.620487.56
1.24181.58
1.86173.67
2.48165.27
3.10256.66
3.72247.94
4.34339.17
4.96330.36
5.58321.52
6.20412.67
6.8243.803
7.09−2.252 × 10^−14

The linear DC motor model: speed falls and current rises in a straight line from free to stall. Real motors also lose speed to heat, and a current limit cuts the curves off early.