I have used these motors before when I was competing on a team in a FIRST robotics competition. They deliver very good performance and are quite inexpensive. The people who run the FRC (FIRST Robotics Challenge) have put a good deal of time into finding the best performing motors for the lowest cost so I am pretty sure that these are the best available.

In order for me to hook these motors up I need to have all the specs on them so I got some information from the FIRST wiki at

(Click to view larger)

This exact motor has been known over the years as the "CIM", "Chiaphua", or "Atwood" motor. The motor is provided in the FRC kit of parts as part number "FR801-001".

Torque and Efficiency curves
Torque (oz-in)Speed (RPM)Current (A)Power (Wo)Efficiency
Free Load053102.700%
Normal Load64.043202720563%
Max Efficiency45.0461419.815465%
Max Power171.7265567.933741%

Motor Specifications
Operating v: 6v - 12v
Nominal v: 12v
No Load RPM: 5310
No Load A: 2.7A
Stall Torque: 343.27 oz-in2424 mN-m
Stall Current: 133A
Kt: 2.58 oz-in/A18.2 mN-m/A
Kv: 443 rpm/V
Efficiency: 65%
RPM - Peak Eff: 4614
Torque - Peak Eff: 45 oz-in/A317.8 mN-m
Current - Peak Eff: 19.8A
Weight: 46 oz(1304g)
Length - for motor: 4.32 in(109.6mm)
Diameter: 2.6 in(66mm)
ShaftDiameter: 0.31 in(8mm)
Shaft Length: 1.4 in(35.6mm)

  • Partially because of the CIM's relatively large size and consequentially low power density, the motor can withstand longer periods at, or near, stall. CIM do not burn out nearly as often as a drill motor or a fisher price motor.
  • Because the CIM is not designed for a specific application like the (obsolete) drill motor, it has little or no wiring bias. This means the motor is equally powerful in forward in reverse. This can be useful in many applications. For example, drive trains which involve a pair of motors running in opposite directions can suffer from driving in a large radius circle when both motors are set to equal speeds. The CIM is relatively immune from such problems in that situation.

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