These small brushed Pololu 20D DC gearmotors can deliver a lot of power for their size. This version has a 12V brushed DC motor with long-life carbon brushes combined with a 25:1 metal spur gearbox. The gearmotor is cylindrical with a diameter of 20mm, and the D-shaped output shaft is 4mm in diameter and extends 18mm from the faceplate of the gearbox.
In general, these kinds of motors can run at voltages above and below their nominal voltages; lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor. This motor will run at 6V but is intended for operation at 12V.
We also stock 100:1 and 250:1 versions of this motor.
Note: Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. In order to avoid damaging the gearbox, we recommend keeping continuously applied loads under 5 kg-cm (75 oz-in). Stalls can also result in rapid (potentially on the order of seconds) thermal damage to the motor windings and brushes, especially for motors like this that can deliver a lot of power for their size; a general recommendation for brushed DC motors is to limit continuous current to approximately 25% of the stall current.
Specifications
| Voltage |
12V |
| Gear ratio |
25:1 |
| No-load speed @ 12V |
550 rpm |
| No-load current @ 12V |
0.08A |
| Stall current @ 12V |
1.6A |
| Stall torque @ 12V |
1.9 kg·cm |
| Max output power @ 12V |
2.6W |
| No-load speed @ 6V |
275 rpm |
| Stall current @ 6V |
0.8A |
| Stall torque @ 6V |
1.0 kg·cm |
| Extended motor shaft? |
N |
| Long-life carbon brushes? |
Y |
| Motor type |
1.6A stall @ 12V CB (carbon brush) |
| Size |
20D × 43.2L mm |
| Weight |
44g |
| Shaft diameter |
4mm |
Performance at Maximum Efficiency
| Max efficiency @ 12V |
37% |
| Speed at max efficiency |
440 rpm |
| Torque at max efficiency |
0.34 kg·cm |
| Current at max efficiency |
0.35A |
| Output power at max efficiency |
1.6 W |
Resources
- Datasheet for Pololu 20D Metal gearmotors
- Dimension Diagrams for Pololu 20D Metal gearmotors
- 3D Models of Pololu 20D Gearmotors
Dimensions
The downloadable diagram shows the dimensions of the 20Dmm line of metal gearmotors (units are mm over [inches]).
Warning: Do not screw too far into the mounting holes as the screws can hit the gears. We recommend screwing no more than 3.5 mm (0.14″) into the M2.5 mounting holes.
Gearmotor accessories
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Gearmotor Face Plate - The gearmotor face plate has two mounting holes threaded for M2.5 screws, and you can use our custom-designed 20D mm metal gearmotor bracket to mount the gearmotor to your project via these mounting holes and the screws that come with the bracket.
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Universal Mounting Hubs - The 4mm diameter gearbox output shaft works with Pololu universal aluminum mounting hub for 4mm shafts, which can be used to mount our larger Pololu wheels (60mm-, 70mm-, 80mm-, and 90mm-diameter) or custom wheels and mechanisms to the gearmotor’s output shaft.
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Scooter Wheel Adaptors - You can use our 4mm scooter wheel adapters to mount many common skateboard, inline skate or scooter wheels to the gearmotor’s output shaft.
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12mm Hex Wheel Adapter - For a general-purpose hex adapter, consider our 12mm hex wheel adapter, which lets you use this motor with many common hobby RC wheels.
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Wild Thumper Wheels - These motors also work with the hex adapters included with the 120mm-diameter Wild Thumper wheels
Pololu 12V 25:1 20D Metal Gearmotor (Long-life Carbon Brush)
