120:1 Mini Plastic Gearmotor, Offset 3mm D-Shaft Output
This compact, inexpensive plastic gearmotor (brushed DC motor with a 120:1 reduction gearbox) is well suited for use in small robots. While intended for operation at 4.5 V, it should run comfortably in the 3 V to 6 V range. The gearbox has a 9.7mm-long, 3 mm-diameter D-shaped output shaft that is offset from but parallel to the motor shaft, and a built-in safety clutch helps protect the gears from excessive loads.
|120 RPM, 80 mA
|1.4 kg⋅cm (20 oz⋅in), 800 mA
Alternatives available with variations in these parameter(s): shaft type no-load speed @ 4.5V extended motor shaft?
|On the blog (0)
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:
Some versions of these gearmotors are also available with an additional 1.5 mm-diameter output shaft that protrudes from the rear of the motor. This 5 mm-long rear shaft rotates at the same speed as the input to the gearbox and offers a way to add an encoder, such as our magnetic encoder for mini plastic gearmotors, to provide motor speed or position feedback:
Magnetic Encoder Kit for Mini Plastic Gearmotors assembled on mini plastic gearmotors with extended motor shafts.
@ 4.5 V
@ 4.5 V
@ 4.5 V
90° output + motor shaft
offset output + motor shaft
|120:1 mini HP
|120:1 mini HP
|120:1 mini HP
|120:1 mini HP
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 our micro metal gearmotors and are compatible with many Pololu wheels and our 3 mm universal mounting hubs. We 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 gearmotors all work with our wide and tall mounting brackets for mini plastic gearmotors.
Details for item #1125
This item has a low-power motor (800 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 motor shaft does not extend past the base of the motor. See the dimension diagram (77k pdf) of this gearmotor for more information.
Exact gear ratio: ``(22×38×44×26×30) / (10×11×11×22×9) ~~ bb(119.76)``
- Wheels and hubs: The mini plastic gearmotor output shaft matches our assortment of Pololu wheels and the Solarbotics RW2i rubber wheel. You can also use our 3 mm universal mounting hubs to mount custom wheels and mechanism to the output shaft, and you can use our 12mm hex wheel adapter to use this motor with many common hobby RC wheels.
- Mounting brackets: Our 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.
- Quadrature encoders: Our magnetic encoder pair kit for mini plastic gearmotors is designed specifically for these motors:
The Magnetic Encoder Kit for Mini Plastic Gearmotors works with our Tall (left) and Wide (right) Mini Plastic Gearmotor Brackets.
- Motor controllers: We offer a number of motor controllers that make it easy to drive these mini plastic gearmotors.
- The Qik 2s9v1 Dual Serial Motor Controller allows variable speed and direction control of two small, brushed DC motors using a simple serial interface. An Arduino library is available to make communication easier and multiple units can be daisy-chained together if you need to independently control many motors from a single serial bus.
- The programmable Baby Orangutan B-328 Robot Controller combines a programmable ATmega328P AVR microcontroller and dual motor driver all in a single, very compact, package and makes interfacing with the motor drivers simple when you use our Pololu AVR library.
- Motor drivers: We also carry a number of basic motor drivers suitable for use with these motors.
- The DRV8835 Dual Motor Driver Carrier is a great option for driving 2 of these mini plastic gearmotors, especially if space is limited. Aside from its tiny size, it has the benefit of supporting two control interfaces: IN/IN and PHASE/ENABLE. We also carry a DRV8835 dual motor driver shield that makes it easy to incorporate this driver into an Arduino project, as well a DRV8835 motor driver kit for the Raspberry Pi.
- The DRV8838 Single Brushed DC Motor Driver Carrier is essentially a smaller, lower-cost, single-channel alternative to our DRV8835 carrier.
- The MAX14870 Single Brushed DC Motor Driver Carrier is another great single-channel alternative that also offers optional current limiting. This driver is also available as Dual MAX14870 motor driver shield for Arduino and a Dual MAX14870 motor driver kit for the Raspberry Pi to make it easy to incorporate into a two-motor application.
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).
People often buy this product together with:
|Pololu Universal Aluminum Mounting Hub for 3mm Shaft, #2-56 Holes (2-Pack)
|Pololu Wheel 32×7mm Pair - Black
|Pololu Wheel 60×8mm Pair - Black