These brushed DC gearmotors are compact and affordable — perfect for building a quick, miniature robot. They are intended for use at 4.5 V, though in general, these kinds of motors can run at voltages above and below this nominal voltage, so they should operate comfortably in the 3 V to 6 V range (rotation can start at voltages as low as 0.5 V). Lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor. The plastic gearbox is protected by a built-in safety clutch that will typically slip before the gear teeth can shear (typically when the load exceeds around 25 oz-in, or 2 kg-cm).
The mini plastic gearmotor family offers two output shaft orientations relative to the motor shaft (offset and 90°), two motor options (normal and high-power, or HP for short), and two gearbox options (120:1 and 180:1). The 120:1 versions are white and the 180:1 versions are yellow. Additionally, some versions of these gearmotors are available with an extended motor shaft that protrudes from the rear of the motor by approximately 4.5 mm. This second shaft has a diameter of 1.5 mm and rotates at the same speed as the input to the gearbox, offering a way to add a custom-built encoder to provide motor speed or position feedback.
|Motor Type||Stall |
@ 4.5 V
@ 4.5 V
|Stall Torque |
@ 4.5 V
90° output + motor shaft
offset output + motor shaft
|1250 mA||150 RPM||25 oz-in||120:1 mini HP||120:1 mini HP||120:1 mini HP||120:1 mini HP|
|low-power||800 mA||120 RPM||20 oz-in||120:1 mini||120:1 mini||120:1 mini||120:1 mini|
|80 RPM||30 oz-in||180:1 mini||180:1 mini|
Note: The stall torque values listed are approximate, and the built-in safety clutch might start slipping at lower torques.
The gearmotors in the table above all have a 3 mm diameter D-shaft output. These shafts are just like the ones on Pololu's micro metal gearmotors and are compatible with many Pololu wheels and Pololu's 3 mm universal mounting hubs. Pololu also carry two low-power, 120:1 mini plastic gearmotors with 2 mm diameter spline outputs: 90° 2mm spline output and offset 2mm spline output. These geamotors all work with Pololu's wide and tall mounting brackets for mini plastic gearmotors.
Details for item #1520
This item has a high-power motor (1250 mA stall current), a 120:1 gearbox, and a 3 mm diameter “D”-shaped output shaft that is offset from but parallel to the motor shaft. The 1.5 mm diameter motor shaft extends approximately 4.5 mm past the base of the motor.
|Dimension diagram of the mini plastic gearmotor with offset 3mm D-shaft output and extended motor shaft (units are mm over [in]).|
This dimension diagram is also available as a downloadable pdf (78k pdf).
- Wheels and hubs: The mini plastic gearmotor output shaft matches Pololu's assortment of Pololu wheels and the Solarbotics RW2 rubber wheel. You can also use Pololu's 3 mm universal mounting hubs to mount custom wheels and mechanism to the output shaft.
- Mounting brackets: Pololu's wide and tall mounting brackets are specifically designed to securely mount these mini plastic gearmotors. Both brackets work with both offset and 90° gearmotor versions, and the two brackets each allow for different mounting options.
- Motor controllers and drivers: Pololu have a number of motor controllers that make it easy to drive these mini plastic gearmotors, including Pololu's qik 2s9v1 dual serial motor controller and Pololu's programmable Baby Orangutan and Orangutan SVP robot controllers. The qik 2s9v1 allows variable speed and direction control of two small, brushed DC motors using a simple serial interface; the Orangutans combine a programmable Atmel AVR microcontroller and dual motor driver all in a single package and make interfacing with the motor drivers simple when you use Pololu's Pololu AVR library. Pololu also carry a number of basic motor drivers suitable for use with these motors, including the DRV8838 single-channel motor driver carrier, the DRV8833 dual motor driver carrier, the DRV8835 dual motor driver carrier, and the TB6612FNG dual motor driver carrier.
The 120:1 gear ratio versions have white plastic bodies and the 180:1 gear ratio versions have yellow plastic bodies (see the main product picture).
Documentation and Resources:
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