N30 DC Micro Metal Gear Motor

Details

This is available in a range of voltages and torques:

• Voltages: 3V 6V 12V
• Torques: 15RPM 30RPM 50RPM 60RPM 100RPM 150RPM 200RPM 300RPM 600RPM 1000RPM

Chosing the appropriate Motor

For a robotic car designed for rough terrain, you should choose a motor with high torque. This is because rough terrain requires more rotational force to overcome obstacles, climb inclines, and maintain traction. In DC geared motors, higher torque is directly associated with lower RPMs.

Therefore, the best combination for your robotic car would be:

Voltage: 12V

RPM: 15 RPM, 30 RPM, 50 RPM, or 60 RPM

Torque and RPM

The relationship between torque and speed (RPM) in a geared motor is inverse due to the gear ratio. A gearbox reduces the motor's output speed while simultaneously multiplying its torque. To handle rough terrain, your robotic car needs to be able to apply significant force to its wheels, and high torque is the measure of that force. The lowest RPM options (15 to 60 RPM) are the result of the highest gear ratios, which provide the greatest torque. A motor with a higher RPM (like 1000 RPM) would be fast but would lack the necessary torque to move the car over rocks or through thick dirt, causing it to stall.

Voltage

The voltage you supply to a DC motor is directly proportional to its speed. A 12V motor is often a good choice because it can handle more power than a 3V or 6V motor. While you can use a lower voltage to get a slower speed from a 12V motor, running it at its rated voltage (12V) will provide the most power and efficiency. A higher voltage also allows for more current, which in turn gives the motor more torque to work with. Since you need a high-torque setup for rough terrain, using the 12V option is the most reliable choice.