These tiny brushed DC gearmotors are intended for use at 6 V, though in general, these kinds of motors can run at voltages above and below this nominal voltage, so they should comfortably operate in the 3 – 9 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 micro metal gearmotors are available in a wide range of gear ratios—from 5:1 up to 1000:1—and offer a choice between three different motors: high-power (HP), medium-power (MP), and standard. With the exception of the 1000:1 gear ratio versions, all of the micro metal gearmotors have the same physical dimensions, so one version can be easily swapped for another if your design requirements change. Please see the micro metal gearmotor comparison table for detailed specifications of all Pololu's micro metal gearmotors. This dynamically-sortable table can help you find the gearmotor that offers the best blend of speed, torque, and current-draw for your particular application. A more basic comparison table is available below.
Some versions of the gearmotors are sold with an additional 1mm-diameter output shaft that protrudes from the rear of the motor. This 4.5mm-long rear shaft rotates at the same speed as the input to the gearbox and offers a way to add an encoder, such as Pololu's magnetic encoder for micro metal gearmotors, to provide motor speed or position feedback.
|Motor Type||Stall |
@ 6 V
@ 6 V
|Stall Torque |
@ 6 V
Gearbox Shaft Only
Gearbox & Motor Shafts
|1600 mA||6000 RPM||2 oz-in||5:1 micro HP|
|3000 RPM||4 oz-in||10:1 micro HP||10:1 micro HP|
|1000 RPM||9 oz-in||30:1 micro HP||30:1 micro HP|
|625 RPM||15 oz-in||50:1 micro HP||50:1 micro HP|
|400 RPM||22 oz-in||75:1 micro HP||75:1 micro HP|
|320 RPM||30 oz-in||100:1 micro HP||100:1 micro HP|
|200 RPM||40 oz-in||150:1 micro HP|
|140 RPM||50 oz-in||210:1 micro HP|
|120 RPM||60 oz-in||250:1 micro HP|
|100 RPM||70 oz-in||298:1 micro HP||298:1 micro HP|
|32 RPM||125 oz-in||1000:1 micro HP|
|700 mA||2200 RPM||3 oz-in||10:1 micro MP||10:1 micro MP|
|730 RPM||8 oz-in||30:1 micro MP|
|420 RPM||13 oz-in||50:1 micro MP|
|290 RPM||17 oz-in||75:1 micro MP||75:1 micro MP|
|220 RPM||19 oz-in||100:1 micro MP||100:1 micro MP|
|150 RPM||24 oz-in||150:1 micro MP|
|75 RPM||46 oz-in||298:1 micro MP|
|low-power||360 mA||2500 RPM||1 oz-in||5:1 micro|
|1300 RPM||2 oz-in||10:1 micro|
|440 RPM||4 oz-in||30:1 micro||30:1 micro|
|250 RPM||7 oz-in||50:1 micro||50:1 micro|
|170 RPM||9 oz-in||75:1 micro|
|120 RPM||12 oz-in||100:1 micro||100:1 micro|
|85 RPM||17 oz-in||150:1 micro|
|60 RPM||27 oz-in||210:1 micro|
|50 RPM||32 oz-in||250:1 micro|
|45 RPM||40 oz-in||298:1 micro||298:1 micro|
|14 RPM||70 oz-in||1000:1 micro|
Note: The 1000:1 gearmotors can generate enough torque to damage themselves. The stall torque values given for those two motors are theoretical, and Pololu strongly recommend you avoid stalling them.
Details for item #994
Exact gear ratio: (25×34×37×35×38) / (12×9×10×13×10) ~~ bb(297.92:1)
|Micro metal gearmotor dimensions (units in mm).|
The gearbox has a long (0.365" or 9.27 mm), 3 mm-diameter D-shaped metal output shaft, and the brass faceplate has two mounting holes threaded for M1.6 screws (1.6 mm diameter, 0.35 mm thread pitch). The gearmotor weighs approximately 0.35 oz (10 g). Versions with the extended motor shaft have a 1mm diameter round shaft that protrudes 4.5 mm from the rear of the motor, between the two motor terminals; this is not pictured in the above dimension diagram. In terms of size, these gearmotors are very similar to Sanyo’s popular 12 mm NA4S DC gearmotors, and gearmotors with this form factor are often referred to as N20 motors.
- Wheels and hubs: The micro metal gearmotor’s output shaft matches Pololu's assortment of Pololu wheels and the Solarbotics RW2 rubber wheel. You can also use Pololu's Pololu universal mounting hubs to mount custom wheels and mechanism to the micro metal gearmotor’s output shaft.
- Mounting brackets: Pololu's mounting bracket (also available in white) and extended mounting bracket are specifically designed to securely mount the gearmotor while enclosing the exposed gears. Pololu recommend the extended mounting bracket for wheels with recessed hubs, such as the Pololu wheel 42×19mm. Pololu's micro metal gearmotors will also work with Pololu's 15.5D mm metal gearmotor bracket pair.
- Quadrature encoders: Pololu offer several quadrature encoders that work with Pololu's micro metal gearmotors.
- Motor controllers and drivers: Pololu have a number of motor controllers that make it easy to drive these micro metal 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.
Selecting the Right Gearmotor
Pololu offer a wide selection of metal gearmotors that offer different combinations of speed and torque. Pololu's metal gearmotor comparison table can help you find the motor that best meets your project’s requirements.
|Some of the Pololu metal gearmotors.|
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Documentation and Resources:
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