Available with a lead time
Expect dispatch between Dec 09 and Dec 12
Quantity Discounts:
These cylindrical brushed DC gearmotors are available in a wide range of gear ratios and with five different motors (two power levels of 6 V motors and three power levels of 12 V motors). The gearmotors all have the same 25 mm diameter case and 4 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 48 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 Pololu's 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.
Rated Voltage | Motor Type | Stall Current | No-Load Current | Gear Ratio | No-Load Speed (RPM) | Extrapolated Stall Torque | Max Power (W) | Without Encoder | With Encoder | |
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(kg · cm) | (oz · in) | |||||||||
12 V | High-Power (HP) | 5.0 A | 250 mA w/o encoder 300 mA with encoder | 1:1 (no gearbox) | 10,000 | 0.4 | 5.5 | 10 | – | item #4840 |
4.4:1 | 2200 | 1.7 | 24 | 9.4 | item #3201 | item #4841 | ||||
9.7:1 | 1000 | 3.9 | 54 | 10 | item #3202 | item #4842 | ||||
20.4:1 | 500 | 7.4 | 100 | 9.4 | item #3203 | item #4843 | ||||
34:1 | 300 | 11 | 150 | 8.9 | item #3204 | item #4844 | ||||
47:1 | 220 | 15 | 210 | 8.4 | item #3205 | item #4845 | ||||
75:1 | 130 | 22 | 310 | – | item #3206 | item #4846 | ||||
99:1 | 100 | 29 | 400 | – | item #3207 | item #4847 | ||||
12 V | Medium-Power (MP) | 1.8 A | 80 mA w/o encoder 100 mA with encoder | 1:1 (no gearbox) | 8200 | 0.17 | 2.4 | 3.5 | – | item #4860 |
4.4:1 | 1800 | 0.71 | 10 | 3.2 | item #3225 | item #4861 | ||||
9.7:1 | 800 | 1.7 | 24 | 3.4 | item #3226 | item #4862 | ||||
20.4:1 | 380 | 3.2 | 44 | 3.1 | item #3227 | item #4863 | ||||
34:1 | 230 | 4.7 | 65 | 2.8 | item #3228 | item #4864 | ||||
47:1 | 170 | 6.4 | 89 | 2.8 | item #3229 | item #4865 | ||||
75:1 | 100 | 8.5 | 120 | 2.3 | item #3230 | item #4866 | ||||
99:1 | 79 | 11 | 150 | 2.3 | item #3231 | item #4867 | ||||
172:1 | 46 | 18 | 250 | 2.1 | item #3232 | item #4868 | ||||
227:1 | 35 | 24 | 330 | – | item #3233 | item #4869 | ||||
12 V | Low-Power (LP) | 0.9 A | 50 mA w/o encoder 60 mA with encoder | 1:1 (no gearbox) | 5600 | 0.14 | 1.9 | 1.8 | – | item #4880 |
4.4:1 | 1200 | 0.53 | 7.4 | 1.7 | item #3249 | item #4881 | ||||
9.7:1 | 580 | 1.3 | 18 | 1.8 | item #3250 | item #4882 | ||||
20.4:1 | 280 | 2.4 | 33 | 1.7 | item #3251 | item #4883 | ||||
34:1 | 170 | 3.7 | 51 | 1.6 | item #3252 | item #4884 | ||||
47:1 | 120 | 4.8 | 67 | 1.4 | item #3253 | item #4885 | ||||
75:1 | 75 | 7.1 | 99 | 1.4 | item #3254 | item #4886 | ||||
99:1 | 57 | 8.7 | 120 | 1.2 | item #3255 | item #4887 | ||||
172:1 | 33 | 13 | 180 | 1.1 | item #3256 | item #4888 | ||||
227:1 | 25 | 16 | 220 | 1.0 | item #3257 | item #4889 | ||||
378:1 | 15 | 23 | 320 | – | item #3258 | item #4890 | ||||
6 V | High-Power (HP) | 6.0 A | 420 mA w/o encoder 500 mA with encoder | 1:1 (no gearbox) | 10,000 | 0.3 | 4 | 7 | – | item #4800 |
4.4:1 | 2200 | 1.2 | 17 | 6.7 | item #1570 | item #4801 | ||||
9.7:1 | 1000 | 2.3 | 32 | 5.9 | item #1571 | item #4802 | ||||
20.4:1 | 480 | 4.8 | 67 | 5.9 | item #1572 | item #4803 | ||||
34:1 | 290 | 6.8 | 94 | 5.1 | item #1573 | item #4804 | ||||
47:1 | 210 | 9.1 | 130 | 4.9 | item #1574 | item #4805 | ||||
75:1 | 130 | 14 | 190 | 4.5 | item #1575 | item #4806 | ||||
99:1 | 99 | 15 | 210 | 3.9 | item #1576 | item #4807 | ||||
172:1 | 57 | 27 | 380 | – | item #1577 | item #4808 | ||||
6 V | Low-Power (LP) | 2.0 A | 100 mA w/o encoder 120 mA with encoder | 1:1 (no gearbox) | 6200 | 0.15 | 2.1 | 2.1 | – | item #4820 |
4.4:1 | 1300 | 0.63 | 8.7 | 2.1 | item #1581 | item #4821 | ||||
9.7:1 | 630 | 1.3 | 18 | 1.9 | item #1582 | item #4822 | ||||
20.4:1 | 290 | 2.5 | 35 | 1.9 | item #1583 | item #4823 | ||||
34:1 | 180 | 3.9 | 54 | 1.7 | item #1584 | item #4824 | ||||
47:1 | 130 | 4.8 | 67 | 1.5 | item #1585 | item #4825 | ||||
75:1 | 80 | 7.5 | 100 | 1.5 | item #1586 | item #4826 | ||||
99:1 | 61 | 9.1 | 130 | 1.4 | item #1587 | item #4827 | ||||
172:1 | 35 | 14 | 190 | 1.2 | item #1588 | item #4828 | ||||
227:1 | 27 | 17 | 240 | 1.1 | item #1589 | item #4829 | ||||
378:1 | 16 | 25 | 350 | – | item #1590 | item #4830 | ||||
499:1 | 12 | 31 | 430 | – | item #1591 | item #4831 |
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 4 kg·cm (55 oz·in), and the recommended upper limit for intermittently permissible torque is 8 kg·cm (110 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 1 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:
Dimensions
The diagram below shows the dimensions of the 25D mm line of gearmotors (units are mm over [inches]). This diagram is also available as a downloadable PDF (171k pdf).
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. Pololu recommend screwing no further than 6 mm (0.24") into the screw hole.
Gearmotor accessories
The face plate has two mounting holes threaded for M3 screws. You can use Pololu's custom-designed 25D 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.
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The 4 mm diameter gearbox output shaft works with Pololu multi-hub wheels as shown in the left picture below. That shaft also works with the Pololu universal aluminum mounting hub for 4mm shafts, which can be used to mount Pololu's larger Pololu wheels (60mm-, 70mm-, 80mm-, and 90mm-diameter) or custom wheels and mechanisms to the gearmotor’s output shaft as shown in the right picture below.
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Alternatively, you could use Pololu's 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 Pololu's 12mm hex wheel adapter, which lets you use this motor with many common hobby RC wheels as shown in the right picture below.
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These are the same type of motors used in the Wild Thumper all-terrain chassis, so the gearbox’s output shaft also works directly with the hex adapters included with the 120mm-diameter Wild Thumper wheels as shown in the image below:
Dagu Wild Thumper wheel 120×60mm (metallic red) and Pololu 25D mm metal gearmotor with encoder. |
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Pololu have a number of motor drivers and motor controllers that work with these 25D mm metal gearmotors. For the LP and MP versions, Pololu recommend Pololu's TB9051FTG-based drivers, for which Pololu have a basic single carrier, a dual-channel shield for Arduino, and a dual-channel expansion board for Raspberry Pi. For the HP versions, Pololu recommend Pololu's VNH5019-based motor drivers (available as single and dual carriers), though these can also be a good choice for the lower-power motors.
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If you are looking for higher-level control interfaces, such as USB, RC, analog voltages, I²C, or TTL serial, consider Pololu's Simple Motor Controllers, Jrk motor controllers, or RoboClaw motor controllers; these controllers are available in various power levels, and the appropriate one depends on the particular version of 25D mm motor you have (we generally recommend a motor controller that can handle continuous currents above the stall current of your motor).
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Pololu have an assortment of Hall effect-based current sensors to choose from for those who need to monitor motor current:
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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.
People often buy this product together with:
Pololu Universal Aluminum Mounting Hub for 4mm Shaft, #4-40 Holes (2-Pack) |
99:1 Metal Gearmotor 25Dx54L mm HP 6V |
Pololu 25D mm Metal Gearmotor Bracket Pair |
Dimensions
Size: | 25D x 56L mm1 |
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Weight: | 94 g |
Shaft diameter: | 4 mm2 |
General specifications
Gear ratio: | 171.79:1 |
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No-load speed @ 6V: | 57 rpm3 |
No-load current @ 6V: | 0.42 A4 |
Stall current @ 6V: | 6.0 A5 |
Stall torque @ 6V: | 27 kg·cm5 |
Motor type: | 6V, 6.0A stall (HP 6V) |
Performance at maximum efficiency
Max efficiency @ 6V: | 30 % |
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Speed at max efficiency: | 46 rpm |
Torque at max efficiency: | 5.2 kg·cm |
Current at max efficiency: | 1.4 A |
Output power at max efficiency: | 2.5 W |
General specifications
Encoders?: | N |
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Notes:
File downloads
Dimension diagram of the Pololu 25D Metal Gearmotors (171k pdf)
3D models of 25D mm gearmotors (9MB zip)
This file contains 3D models (in the step file format) of the 25D mm gearmotors with and without encoders.
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