Overview
These cylindrical brushed DC gearmotors are available in a wide range of gear ratios and with five different motors (two power levels of 6Â V motors and three power levels of 12Â V motors). The gearmotors all have the same 25Â mm diameter case and 4Â mm diameter gearbox output shaft, so it is generally easy to swap one version for another if your design requirements change (though the length of the gearbox tends to increase with the gear ratio). Each version is also optionally available with an integrated 48Â CPR quadrature encoder. See the 25D metal gearmotor datasheet (2MB pdf) for more information, including detailed performance graphs for each gearmotor version. You can also use our dynamically sortable 25D gearmotor comparison table to search for the version that offers the best combination of speed, torque, and current draw for your particular application. A more basic comparison table is available below.
Note: The listed stall torques and currents are theoretical extrapolations; units will typically stall well before these points as the motors heat up. Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. The recommended upper limit for continuously applied loads is 4Â kg?cm (55Â oz?in), and the recommended upper limit for intermittently permissible torque is 8Â kg?cm (110Â oz?in). Stalls can also result in rapid (potentially on the order of seconds) thermal damage to the motor windings and brushes; a general recommendation for brushed DC motor operation is 25% or less of the stall current.
In general, these kinds of motors can run at voltages above and below their nominal voltages (they can begin rotating at voltages as low as 1Â V); lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor.
Details for item #1577
Exact gear ratio: ``(22×20×22×22×22×22×24) / (12×12×10×10×10×10×10) ~~ bb(171.79:1)``
Dimensions
The diagram below shows the dimensions of the 25DÂ mm line of gearmotors (units are mm over [inches]). This diagram is also available as a downloadable PDF (171k pdf).
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Dimensions of the Pololu 25D mm metal gearmotors without encoders. Units are mm over [inches]. |
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Warning: Do not screw too far into the mounting holes as the screws can hit the gears. We recommend screwing no further than 6Â mm (0.24?) into the screw hole.
Gearmotor accessories
- Mounting brackets: The face plate has two mounting holes threaded for M3 screws. You can use our custom-designed 25DÂ mm metal gearmotor bracket (shown in the picture below) to mount the gearmotor to your project via these mounting holes and the screws that come with the bracket.
 | Pololu 25D mm metal gearmotor bracket pair. |
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 | Pololu 25D mm gearmotor with bracket. |
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 | Pololu 80×10mm multi-hub wheel on a Pololu 25DÂ mm metal gearmotor with encoder. |
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 | Pololu 60×8mm wheel with 4mm hub adapter on Pololu 25DÂ mm metal gearmotor with encoder. |
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Alternatively, you could use our 4mm scooter wheel adapter to mount many common scooter, skateboard, and inline skate wheels to the gearmotor’s output shaft as shown in the left picture below. For a general-purpose hex adapter, consider our 12mm hex wheel adapter, which lets you use this motor with many common hobby RC wheels as shown in the right picture below.
 | A 25DÂ mm gearmotor with encoder connected to a scooter wheel by the 4mm scooter wheel adapter. |
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 | 12mm hex wheel adapter for 4mm shaft on a 25DÂ mm metal gearmotor with encoder. |
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 | TB9051FTG Single Motor Driver Carrier. |
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 | Pololu dual VNH5019 motor driver shield for Arduino. |
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If you are looking for higher-level control interfaces, such as USB, RC, analog voltages, I²C, or TTL serial, consider our Motoron motor controllers, Jrk motor controllers, or RoboClaw motor controllers; these controllers are available in various power levels several of which can handle the 25DÂ mm metal gearmotors (we generally recommend a motor controller that can handle continuous currents above the stall current of your motor).
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Three Motoron M3H550 controllers being controlled by a Raspberry Pi. |
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Jrk G2 21v3 USB Motor Controller with Feedback. |
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RoboClaw 2×7A Motor Controller (V5B) in its included case. |
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- Current sensors: We have an assortment of current sensors to choose from for those who need to monitor motor current:
 | ACS711EX current sensor carrier -15.5A to +15.5A. |
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 | ACS724LLCTR-05AB Current Sensor Carrier -5A to +5A. |
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Selecting the right gearmotor
We offer a wide selection of metal gearmotors that offer different combinations of speed and torque. Our metal gearmotor comparison table can help you find the motor that best meets your project’s requirements.
