These tiny, high-torque gearmotors have the highest gear ratio of any motor Pololu sell, which makes them a great choice for applications that require extremely low motor speeds. With no load, the 1000:1 micro metal gearmotor HP output shaft turns at approximately 32 RPM at 6 V, and Pololu were able to achieve rotation rates of around 2.5 RPM at 0.5 V on a test unit (note that performance will vary slightly from unit to unit). The lower-power 1000:1 micro metal gearmotor is even slower, with a no-load rotation rate of approximately 14 RPM at 6 V, and Pololu were able to a achieve smooth rotation speed of around 1 RPM at 0.6 V on a test unit.
Note: Because of the high gear ratio, these motors can generate enough torque to damage themselves, so you should avoid stalling them.
These motors 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.
Micro Metal Gearmotor Versions
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 two different motors: high-power (HP) 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 a custom-built encoder 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 #1596
Exact gear ratio: ``(25×34×35×34×34×34×27) / (12×9×12×14×14×14×9) ~~ bb(986.41:1)``
The diagram below shows the dimensions for this gearmotor. The 1000:1 gear ratio version of the micro metal gearmotor has a longer gearbox than other micro metal gearmotor versions (12.5 mm for the 1000:1 compared to 9 mm for all gear ratios). All the other dimensions match those of the other micro metal gearmotor versions.
|1000:1 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). It weighs approximately 0.37 oz (11 g).
Note: Due to the longer gearbox, the 1000:1 micro metal gearmotors do work with the encoder for Pololu wheel 42×19mm. These gearmotors can be used with Pololu's micro metal gearmotor bracket and extended bracket, but these brackets will not cover the entire gearbox the way they do when used with other gear ratios of micro metal gearmotors.
- 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 the Pololu universal mounting hub 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 make it easy to mount the gearmotor. Pololu recommend the extended mounting bracket for wheels with recessed hubs, such as the Pololu wheel 42×19mm. Note that when used with the longer gearbox found on the 1000:1 gear ratio version of the micro metal gearmotor, these brackets do not fully enclose the exposed gears they way they do in the right picture below. This picture shows another version of the micro metal gearmotor.
- Motor Controllers: 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 inexpensive 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. All of the above controllers use the TB6612FNG dual motor driver, for which Pololu also offer a simple carrier board.
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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