# HP 12V Motor with 48 CPR Encoder for 25D mm Metal Gearmotors (No Gearbox)

**Type:** Product page · **SKU:** POLOLU-4840 · **Brand:** [Pololu](https://core-electronics.com.au/brands/pololu-australia)
**Page:** https://core-electronics.com.au/hp-12v-motor-with-48-cpr-encoder-for-25d-mm-metal-gearmotors-no-gearbox.html ([markdown](https://core-electronics.com.au/hp-12v-motor-with-48-cpr-encoder-for-25d-mm-metal-gearmotors-no-gearbox.html.md))

This is the motor and encoder portion of our high-power (HP), 12V 25D mm metal gearmotors with 48 CPR encoders. It does not include a gearbox, but the...

## Pricing

- **Price:** $81.45 (inc GST) — $74.05 AUD, exc GST
- **Quantity discounts:** 6+ $71.08 (exc GST) · 12+ $68.86 (exc GST)

## Availability & dispatch

- Available with a lead time — expect dispatch between Aug 21 and Aug 24.

## Description

| [![](https://core-electronics.com.au/attachments/localcontent/0J4660_14096e907c3.jpg)](https://core-electronics.com.au/attachments/localcontent/0J4660_15085abf634.jpg) |
|---|

This motor with integrated 48 CPR (counts per revolution) quadrature encoder is intended as a replacement high-power (HP) 12 V motor with encoder for Pololu's [25D mm metal gearmotors](https://core-electronics.com.au/components/motors/metal-gearmotors/25d-mm.html). It is intended for use at 12 V, but in general, these kinds of motors can run at voltages above and below this nominal voltage. Lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor.

The output shaft has a non-removable pinion gear that works with all of Pololu's 25D mm gearmotor gearboxes. Note that Pololu do not sell the 25D mm gearboxes separately, but if you have a gearmotor with a damaged motor or encoder (or if you want to effectively add an encoder to a version without an encoder), you can transfer the gearbox to this replacement motor.

The motor has a diameter of 24.2 mm (0.95 in) and a length of approximately 43 mm (1.7 in) from the top of the motor can to the bottom of the encoder. The top of the motor has two mounting holes threaded for M3 screws. These mounting holes are 17 mm apart and form a line with the motor shaft at the center. The mounting holes have a depth of approximately 2 mm.

Other motor windings with identical dimensions and pinion gears are also available, resulting in five total options:

- [High-power 6 V motor with encoder](https://core-electronics.com.au/hp-6v-motor-with-48-cpr-encoder-for-25d-mm-metal-gearmotors-no-gearbox.html)
- [Low-power 6 V motor with encoder](https://core-electronics.com.au/lp-6v-motor-with-48-cpr-encoder-for-25d-mm-metal-gearmotors-no-gearbox.html)
- High-power 12 V motor with encoder (this product)
- [Medium-power 12 V motor with encoder](https://core-electronics.com.au/mp-12v-motor-with-48-cpr-encoder-for-25d-mm-metal-gearmotors-no-gearbox.html)
- [Low-power 12 V motor with encoder](https://core-electronics.com.au/lp-12v-motor-with-48-cpr-encoder-for-25d-mm-metal-gearmotors-no-gearbox.html)

These motors are functionally identical to the previous versions Pololu carried [without end caps](https://core-electronics.com.au/catalog/product/view/sku/POLOLU-3212) (they use the same motor and encoder). The black plastic end cap is easily removable if you need to access the encoder or want to slightly reduce the overall motor size, but there is a little bit of base plastic that will remain, as shown in the picture below:

| [![](https://core-electronics.com.au/attachments/localcontent/0J9896_208365f8403.jpg)](https://core-electronics.com.au/attachments/localcontent/0J9896_1838415ee88.jpg) |
|---|

**Pinion gear specs**

- Metric with module m = 0.4
- Number of teeth: 12
- Face thickness: 2.5 mm
- Pressure angle: 20°
- Gear position: 4.5 mm from top of motor to top of gear

**Gearmotor options**

You will typically want to combine this motor with a gearbox to give it a more appropriate combination of torque and speed (without a gearbox, it offers very high speed with very low torque). The [HP 12V versions](https://core-electronics.com.au/category/186/12v-high-power-hp-25d-mm-gearmotors) of Pololu's 25D mm metal gearmotors consist of this motor combined with different gearboxes. Pololu do not carry the gearboxes by themselves, so unless you are looking at this as a replacement motor for a compatible gearbox you already have, Pololu strongly recommend you consider getting a preassembled gearmotor with the gear ratio that best suits your project requirements.

| Rated Voltage | Motor Type | Stall Current | No-Load Current | Gear Ratio | No-Load Speed (RPM) | Extrapolated Stall Torque | Max Power (W) | ![](https://core-electronics.com.au/attachments/localcontent/0J2644_3481ae143f.jpg)  Without Encoder | ![](https://core-electronics.com.au/attachments/localcontent/0J9890_6816cc81bc.jpg)  With Encoder |
|---|---|---|---|---|---|---|---|---|---|
| (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](https://core-electronics.com.au/hp-12v-motor-with-48-cpr-encoder-for-25d-mm-metal-gearmotors-no-gearbox.html) |
| 4.4:1 | 2200 | 1.7 | 24 | 9.4 | [item #3201](https://core-electronics.com.au/4-4-1-metal-gearmotor-25dx48l-mm-hp-12v.html) | [item #4841](https://core-electronics.com.au/4-4-1-metal-gearmotor-25dx63l-mm-hp-12v-with-48-cpr-encoder.html) |
| 9.7:1 | 1000 | 3.9 | 54 | 10 | [item #3202](https://core-electronics.com.au/9-7-1-metal-gearmotor-25dx48l-mm-hp-12v.html) | [item #4842](https://core-electronics.com.au/9-7-1-metal-gearmotor-25dx63l-mm-hp-12v-with-48-cpr-encoder.html) |
| 20.4:1 | 500 | 7.4 | 100 | 9.4 | [item #3203](https://core-electronics.com.au/20-4-1-metal-gearmotor-25dx50l-mm-hp-12v.html) | [item #4843](https://core-electronics.com.au/20-4-1-metal-gearmotor-25dx65l-mm-hp-12v-with-48-cpr-encoder.html) |
| 34:1 | 300 | 11 | 150 | 8.9 | [item #3204](https://core-electronics.com.au/34-1-metal-gearmotor-25dx52l-mm-hp-12v.html) | [item #4844](https://core-electronics.com.au/34-1-metal-gearmotor-25dx67l-mm-hp-12v-with-48-cpr-encoder.html) |
| 47:1 | 220 | 15 | 210 | 8.4 | [item #3205](https://core-electronics.com.au/47-1-metal-gearmotor-25dx52l-mm-hp-12v.html) | [item #4845](https://core-electronics.com.au/47-1-metal-gearmotor-25dx67l-mm-hp-12v-with-48-cpr-encoder.html) |
| 75:1 | 130 | 22 | 310 | – | [item #3206](https://core-electronics.com.au/75-1-metal-gearmotor-25dx54l-mm-hp-12v.html) | [item #4846](https://core-electronics.com.au/75-1-metal-gearmotor-25dx69l-mm-hp-12v-with-48-cpr-encoder.html) |
| 99:1 | 100 | 29 | 400 | – | [item #3207](https://core-electronics.com.au/99-1-metal-gearmotor-25dx54l-mm-hp-12v.html) | [item #4847](https://core-electronics.com.au/99-1-metal-gearmotor-25dx69l-mm-hp-12v-with-48-cpr-encoder.html) |
|  |
|  |
| **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](https://core-electronics.com.au/mp-12v-motor-with-48-cpr-encoder-for-25d-mm-metal-gearmotors-no-gearbox.html) |
| 4.4:1 | 1800 | 0.71 | 10 | 3.2 | [item #3225](https://core-electronics.com.au/4-4-1-metal-gearmotor-25dx48l-mm-mp-12v.html) | [item #4861](https://core-electronics.com.au/4-4-1-metal-gearmotor-25dx63l-mm-mp-12v-with-48-cpr-encoder.html) |
| 9.7:1 | 800 | 1.7 | 24 | 3.4 | [item #3226](https://core-electronics.com.au/9-7-1-metal-gearmotor-25dx48l-mm-mp-12v.html) | [item #4862](https://core-electronics.com.au/9-7-1-metal-gearmotor-25dx63l-mm-mp-12v-with-48-cpr-encoder.html) |
| 20.4:1 | 380 | 3.2 | 44 | 3.1 | [item #3227](https://core-electronics.com.au/20-4-1-metal-gearmotor-25dx50l-mm-mp-12v.html) | [item #4863](https://core-electronics.com.au/20-4-1-metal-gearmotor-25dx65l-mm-mp-12v-with-48-cpr-encoder.html) |
| 34:1 | 230 | 4.7 | 65 | 2.8 | [item #3228](https://core-electronics.com.au/34-1-metal-gearmotor-25dx52l-mm-mp-12v.html) | [item #4864](https://core-electronics.com.au/34-1-metal-gearmotor-25dx67l-mm-mp-12v-with-48-cpr-encoder.html) |
| 47:1 | 170 | 6.4 | 89 | 2.8 | [item #3229](https://core-electronics.com.au/47-1-metal-gearmotor-25dx52l-mm-mp-12v.html) | [item #4865](https://core-electronics.com.au/47-1-metal-gearmotor-25dx67l-mm-mp-12v-with-48-cpr-encoder.html) |
| 75:1 | 100 | 8.5 | 120 | 2.3 | [item #3230](https://core-electronics.com.au/75-1-metal-gearmotor-25dx54l-mm-mp-12v.html) | [item #4866](https://core-electronics.com.au/75-1-metal-gearmotor-25dx69l-mm-mp-12v-with-48-cpr-encoder.html) |
| 99:1 | 79 | 11 | 150 | 2.3 | [item #3231](https://core-electronics.com.au/99-1-metal-gearmotor-25dx54l-mm-mp-12v.html) | [item #4867](https://core-electronics.com.au/99-1-metal-gearmotor-25dx69l-mm-mp-12v-with-48-cpr-encoder.html) |
| 172:1 | 46 | 18 | 250 | 2.1 | [item #3232](https://core-electronics.com.au/172-1-metal-gearmotor-25dx56l-mm-mp-12v.html) | [item #4868](https://core-electronics.com.au/172-1-metal-gearmotor-25dx71l-mm-mp-12v-with-48-cpr-encoder.html) |
| 227:1 | 35 | 24 | 330 | – | [item #3233](https://core-electronics.com.au/227-1-metal-gearmotor-25dx56l-mm-mp-12v.html) | [item #4869](https://core-electronics.com.au/227-1-metal-gearmotor-25dx71l-mm-mp-12v-with-48-cpr-encoder.html) |
|  |
|  |
| **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](https://core-electronics.com.au/lp-12v-motor-with-48-cpr-encoder-for-25d-mm-metal-gearmotors-no-gearbox.html) |
| 4.4:1 | 1200 | 0.53 | 7.4 | 1.7 | [item #3249](https://core-electronics.com.au/4-4-1-metal-gearmotor-25dx48l-mm-lp-12v.html) | [item #4881](https://core-electronics.com.au/4-4-1-metal-gearmotor-25dx63l-mm-lp-12v-with-48-cpr-encoder.html) |
| 9.7:1 | 580 | 1.3 | 18 | 1.8 | [item #3250](https://core-electronics.com.au/9-7-1-metal-gearmotor-25dx48l-mm-lp-12v.html) | [item #4882](https://core-electronics.com.au/9-7-1-metal-gearmotor-25dx63l-mm-lp-12v-with-48-cpr-encoder.html) |
| 20.4:1 | 280 | 2.4 | 33 | 1.7 | [item #3251](https://core-electronics.com.au/20-4-1-metal-gearmotor-25dx50l-mm-lp-12v.html) | [item #4883](https://core-electronics.com.au/20-4-1-metal-gearmotor-25dx65l-mm-lp-12v-with-48-cpr-encoder.html) |
| 34:1 | 170 | 3.7 | 51 | 1.6 | [item #3252](https://core-electronics.com.au/34-1-metal-gearmotor-25dx52l-mm-lp-12v.html) | [item #4884](https://core-electronics.com.au/34-1-metal-gearmotor-25dx67l-mm-lp-12v-with-48-cpr-encoder.html) |
| 47:1 | 120 | 4.8 | 67 | 1.4 | [item #3253](https://core-electronics.com.au/47-1-metal-gearmotor-25dx52l-mm-lp-12v.html) | [item #4885](https://core-electronics.com.au/47-1-metal-gearmotor-25dx67l-mm-lp-12v-with-48-cpr-encoder.html) |
| 75:1 | 75 | 7.1 | 99 | 1.4 | [item #3254](https://core-electronics.com.au/75-1-metal-gearmotor-25dx54l-mm-lp-12v.html) | [item #4886](https://core-electronics.com.au/75-1-metal-gearmotor-25dx69l-mm-lp-12v-with-48-cpr-encoder.html) |
| 99:1 | 57 | 8.7 | 120 | 1.2 | [item #3255](https://core-electronics.com.au/99-1-metal-gearmotor-25dx54l-mm-lp-12v.html) | [item #4887](https://core-electronics.com.au/99-1-metal-gearmotor-25dx69l-mm-lp-12v-with-48-cpr-encoder.html) |
| 172:1 | 33 | 13 | 180 | 1.1 | [item #3256](https://core-electronics.com.au/172-1-metal-gearmotor-25dx56l-mm-lp-12v.html) | [item #4888](https://core-electronics.com.au/172-1-metal-gearmotor-25dx71l-mm-lp-12v-with-48-cpr-encoder.html) |
| 227:1 | 25 | 16 | 220 | 1.0 | [item #3257](https://core-electronics.com.au/227-1-metal-gearmotor-25dx56l-mm-lp-12v.html) | [item #4889](https://core-electronics.com.au/227-1-metal-gearmotor-25dx71l-mm-lp-12v-with-48-cpr-encoder.html) |
| 378:1 | 15 | 23 | 320 | – | [item #3258](https://core-electronics.com.au/378-1-metal-gearmotor-25dx58l-mm-lp-12v.html) | [item #4890](https://core-electronics.com.au/378-1-metal-gearmotor-25dx73l-mm-lp-12v-with-48-cpr-encoder.html) |
|  |
|  |
| **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](https://core-electronics.com.au/hp-6v-motor-with-48-cpr-encoder-for-25d-mm-metal-gearmotors-no-gearbox.html) |
| 4.4:1 | 2200 | 1.2 | 17 | 6.7 | [item #1570](https://core-electronics.com.au/4-4-1-metal-gearmotor-25dx48l-mm-hp.html) | [item #4801](https://core-electronics.com.au/4-4-1-metal-gearmotor-25dx63l-mm-hp-6v-with-48-cpr-encoder.html) |
| 9.7:1 | 1000 | 2.3 | 32 | 5.9 | [item #1571](https://core-electronics.com.au/9-7-1-metal-gearmotor-25dx48l-mm-hp.html) | [item #4802](https://core-electronics.com.au/9-7-1-metal-gearmotor-25dx63l-mm-hp-6v-with-48-cpr-encoder.html) |
| 20.4:1 | 480 | 4.8 | 67 | 5.9 | [item #1572](https://core-electronics.com.au/20-4-1-metal-gearmotor-25dx50l-mm-hp.html) | [item #4803](https://core-electronics.com.au/20-4-1-metal-gearmotor-25dx65l-mm-hp-6v-with-48-cpr-encoder.html) |
| 34:1 | 290 | 6.8 | 94 | 5.1 | [item #1573](https://core-electronics.com.au/34-1-metal-gearmotor-25dx52l-mm-hp.html) | [item #4804](https://core-electronics.com.au/34-1-metal-gearmotor-25dx67l-mm-hp-6v-with-48-cpr-encoder.html) |
| 47:1 | 210 | 9.1 | 130 | 4.9 | [item #1574](https://core-electronics.com.au/47-1-metal-gearmotor-25dx52l-mm-hp.html) | [item #4805](https://core-electronics.com.au/47-1-metal-gearmotor-25dx67l-mm-hp-6v-with-48-cpr-encoder.html) |
| 75:1 | 130 | 14 | 190 | 4.5 | [item #1575](https://core-electronics.com.au/75-1-metal-gearmotor-25dx54l-mm-hp.html) | [item #4806](https://core-electronics.com.au/75-1-metal-gearmotor-25dx69l-mm-hp-6v-with-48-cpr-encoder.html) |
| 99:1 | 99 | 15 | 210 | 3.9 | [item #1576](https://core-electronics.com.au/99-1-metal-gearmotor-25dx54l-mm-hp.html) | [item #4807](https://core-electronics.com.au/99-1-metal-gearmotor-25dx69l-mm-hp-6v-with-48-cpr-encoder.html) |
| 172:1 | 57 | 27 | 380 | – | [item #1577](https://core-electronics.com.au/172-1-metal-gearmotor-25dx56l-mm-hp.html) | [item #4808](https://core-electronics.com.au/172-1-metal-gearmotor-25dx71l-mm-hp-6v-with-48-cpr-encoder.html) |
|  |
|  |
| **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](https://core-electronics.com.au/lp-6v-motor-with-48-cpr-encoder-for-25d-mm-metal-gearmotors-no-gearbox.html) |
| 4.4:1 | 1300 | 0.63 | 8.7 | 2.1 | [item #1581](https://core-electronics.com.au/4-4-1-metal-gearmotor-25dx48l-mm.html) | [item #4821](https://core-electronics.com.au/4-4-1-metal-gearmotor-25dx63l-mm-lp-6v-with-48-cpr-encoder.html) |
| 9.7:1 | 630 | 1.3 | 18 | 1.9 | [item #1582](https://core-electronics.com.au/9-7-1-metal-gearmotor-25dx48l-mm.html) | [item #4822](https://core-electronics.com.au/9-7-1-metal-gearmotor-25dx63l-mm-lp-6v-with-48-cpr-encoder.html) |
| 20.4:1 | 290 | 2.5 | 35 | 1.9 | [item #1583](https://core-electronics.com.au/20-4-1-metal-gearmotor-25dx50l-mm.html) | [item #4823](https://core-electronics.com.au/20-4-1-metal-gearmotor-25dx65l-mm-lp-6v-with-48-cpr-encoder.html) |
| 34:1 | 180 | 3.9 | 54 | 1.7 | [item #1584](https://core-electronics.com.au/34-1-metal-gearmotor-25dx52l-mm.html) | [item #4824](https://core-electronics.com.au/34-1-metal-gearmotor-25dx67l-mm-lp-6v-with-48-cpr-encoder.html) |
| 47:1 | 130 | 4.8 | 67 | 1.5 | [item #1585](https://core-electronics.com.au/47-1-metal-gearmotor-25dx52l-mm.html) | [item #4825](https://core-electronics.com.au/47-1-metal-gearmotor-25dx67l-mm-lp-6v-with-48-cpr-encoder.html) |
| 75:1 | 80 | 7.5 | 100 | 1.5 | [item #1586](https://core-electronics.com.au/75-1-metal-gearmotor-25dx54l-mm.html) | [item #4826](https://core-electronics.com.au/75-1-metal-gearmotor-25dx69l-mm-lp-6v-with-48-cpr-encoder.html) |
| 99:1 | 61 | 9.1 | 130 | 1.4 | [item #1587](https://core-electronics.com.au/99-1-metal-gearmotor-25dx54l-mm.html) | [item #4827](https://core-electronics.com.au/99-1-metal-gearmotor-25dx69l-mm-lp-6v-with-48-cpr-encoder.html) |
| 172:1 | 35 | 14 | 190 | 1.2 | [item #1588](https://core-electronics.com.au/172-1-metal-gearmotor-25dx56l-mm.html) | [item #4828](https://core-electronics.com.au/172-1-metal-gearmotor-25dx71l-mm-lp-6v-with-48-cpr-encoder.html) |
| 227:1 | 27 | 17 | 240 | 1.1 | [item #1589](https://core-electronics.com.au/227-1-metal-gearmotor-25dx56l-mm.html) | [item #4829](https://core-electronics.com.au/227-1-metal-gearmotor-25dx71l-mm-lp-6v-with-48-cpr-encoder.html) |
| 378:1 | 16 | 25 | 350 | – | [item #1590](https://core-electronics.com.au/378-1-metal-gearmotor-25dx58l-mm.html) | [item #4830](https://core-electronics.com.au/378-1-metal-gearmotor-25dx73l-mm-lp-6v-with-48-cpr-encoder.html) |
| 499:1 | 12 | 31 | 430 | – | [item #1591](https://core-electronics.com.au/499-1-metal-gearmotor-25dx58l-mm.html) | [item #4831](https://core-electronics.com.au/499-1-metal-gearmotor-25dx73l-mm-lp-6v-with-48-cpr-encoder.html) |

**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.

| [![](https://core-electronics.com.au/attachments/localcontent/0J9893_21422953e62.jpg)](https://core-electronics.com.au/attachments/localcontent/0J9893_262325afe5b.jpg) |
|---|
| 25D mm metal gearmotor with 48 CPR encoder (with end cap removed). |

| [![](https://core-electronics.com.au/attachments/localcontent/0J9897_1319650da27.jpg)](https://core-electronics.com.au/attachments/localcontent/0J9897_133721b72ae.jpg) |
|---|

**Using the encoder**

A two-channel Hall effect encoder is used to sense the rotation of a magnetic disk on a rear protrusion of the motor shaft. The quadrature encoder provides a resolution of 48 counts per revolution of the motor shaft when counting both edges of both channels. To compute the counts per revolution of the gearbox output, multiply the gear ratio by 48. The motor/encoder has six color-coded, 11" (28 cm) leads terminated by a 1×6 female header with a 0.1" pitch, as shown in the main product picture. This header works with standard [0.1" male headers](https://core-electronics.com.au/0-100-2-54-mm-breakaway-male-header-1x40-pin-straight.html) and Pololu's male [jumper](https://core-electronics.com.au/prototyping/prototyping-wire.html) and [precrimped wires](https://core-electronics.com.au/wire/pre-crimped-terminals.html). If this header is not convenient for your application, you can pull the crimped wires out of the header or cut the header off. The following table describes the wire functions:

| Color | Function |
|---|---|
| Red | motor power (connects to one motor terminal) |
| Black | motor power (connects to the other motor terminal) |
| Green | encoder GND |
| Blue | encoder Vcc (3.5 – 20 V) |
| Yellow | encoder A output |
| White | encoder B output |

The Hall sensor requires an input voltage, Vcc, between 3.5 and 20 V and draws a maximum of 10 mA. The A and B outputs are square waves from 0 V to Vcc approximately 90° out of phase. The frequency of the transitions tells you the speed of the motor, and the order of the transitions tells you the direction. The following oscilloscope capture shows the A and B (yellow and white) encoder outputs using a motor voltage of 6 V and a Hall sensor Vcc of 5 V:

| ![](https://core-electronics.com.au/attachments/localcontent/0J3481_8551781c80e.jpg) |
|---|
| Encoder A and B outputs for 25D mm HP 6V metal gearmotor with 48 CPR encoder (motor running at 6 V). |

By counting both the rising and falling edges of both the A and B outputs, it is possible to get 48 counts per revolution of the motor shaft. Using just a single edge of one channel results in 12 counts per revolution of the motor shaft, so the frequency of the A output in the above oscilloscope capture is 12 times the motor rotation frequency.

**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](https://core-electronics.com.au/search/compare/51)** can help you find the motor that best meets your project’s requirements.

| ![](https://core-electronics.com.au/attachments/localcontent/0J9775_551831ace88.jpg) |
|---|

**Dimensions**

 | Size: | 25D x 46L mm[1](https://core-electronics.com.au/#note1) |
|---|---|
| Weight: | 60 g |

**General specifications**

 | Gear ratio: | 1:1[2](https://core-electronics.com.au/#note2) |
|---|---|
| No-load speed @ 12V: | 10000 rpm[3](https://core-electronics.com.au/#note3) |
| No-load current @ 12V: | 0.30 A[4](https://core-electronics.com.au/#note4) |
| Stall current @ 12V: | 5.0 A[5](https://core-electronics.com.au/#note5) |
| Stall torque @ 12V: | 0.4 kg·cm[5](https://core-electronics.com.au/#note5) |
| Max output power @ 12V: | 10 W |
| No-load speed @ 6V: | 5000 rpm[6](https://core-electronics.com.au/#note6) |
| Stall current @ 6V: | 2.5 A[6](https://core-electronics.com.au/#note6) |
| Stall torque @ 6V: | 0.2 kg·cm[6](https://core-electronics.com.au/#note6) |
| Motor type: | 12V, 5.0A stall (HP 12V) |
| Lead length: | 8 in[7](https://core-electronics.com.au/#note7) |
| Encoders?: | Y |

**Notes:**

1Length does not include the motor shaft. See dimension diagram for details.2This motor does not have a gearbox.3Typical; ±20%.4Typical, ±50%; no-load current depends on internal friction, which is affected by many factors, including ambient temperature and duration of motor operation.5Stalling is likely to damage the motor. Stall parameters come from a theoretical extrapolation of performance at loads far from stall. As the motor heats up, as happens as it approaches an actual stall, the stall torque and current decrease.6This motor will run at 6 V but is intended for operation at 12 V.7May vary by a few inches. **File downloads**

- **Datasheet for Pololu 25D Metal Gearmotors (2MB pdf)**
- **Dimension diagram of the Pololu 25D Metal Gearmotors (171k pdf)**
- **3D models of 25D mm gearmotors (10MB zip)**
    
    This file contains 3D models (in the step file format) of the 25D mm gearmotors with and without encoders.

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/i/m/image_9066.jpg)