120:1 Mini Plastic Gearmotor, Offset 2mm Spline Output
This compact, inexpensive, low-current gearmotor (brushed DC motor with a 120:1 reduction gearbox) is well suited for use in small robots. At 4.5 V, it has a free-run speed of 120 RPM and a stall torque of approximately 20 oz-in (however, the built-in safety clutch might start slipping before the stall torque is reached). The splined output shaft has a crest diameter of 2 mm and is offset from but parallel to the motor shaft. Though the product picture shows two gearmotors, this product is for a single motor.
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|Pololu mini plastic gearmotor offset output with opened gearbox.|
This brushed DC gearmotor is very compact and weighs only 0.7 ounces (19.5 grams) — perfect for building a quick, miniature robot. The recommended operating voltage range for this motor is 3 to 6 V, though the gearmotor can start rotating at voltages as low as 0.6 V. At 4.5 V, the motor has a free-run current of 80 mA and a stall current of 800 mA; this relatively low current draw makes this a great match for our qik 2s9v1 dual serial motor controller and programmable Orangutan robot controllers. The stall current, torque, and rotation speed will approximately scale linearly with the motor voltage. The gearbox is protected by a built-in safety clutch that will typically slip before gear teeth can shear.
|Dimension diagram of the mini plastic gearmotor with offset 2mm spline output (units are mm over [in]).|
This dimension diagram is also available as a downloadable pdf (76k pdf).
This gearmotor features a splined, chrome-finish output shaft with a 2mm-crest diameter. This shaft can be used with custom wheels or with our adapter for LEGO wheels. The gearbox output shaft is offset from but parallel to the motor shaft.
We have many more versions of these mini plastic gearmotors available with 3 mm diameter “D”-shaped output shafts (just like the ones on our micro metal gearmotors) that are compatible with many Pololu wheels and our 3 mm universal mounting hubs. These versions offer 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). Additionally, some of these versions 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. The following table shows all of the mini plastic gearmotors that have 3 mm D-shafts:
@ 4.5 V
@ 4.5 V
@ 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.
People often buy this product together with:
|2mm Shaft Adapter for LEGO Wheels (Pair)|
|120:1 Mini Plastic Gearmotor, 90° 2mm Spline Output|
|200:1 Plastic Gearmotor, 90° Output|