# 24V Motor with 64 CPR Encoder for 37D mm Metal Gearmotors (No Gearbox, Helical Pinion)

**Type:** Product page · **SKU:** POLOLU-4690 · **Brand:** [Pololu](https://core-electronics.com.au/brands/pololu-australia)
**Page:** https://core-electronics.com.au/24v-motor-with-64-cpr-encoder-for-37d-mm-metal-gearmotors-no-gearbox-helical-pinion.html ([markdown](https://core-electronics.com.au/24v-motor-with-64-cpr-encoder-for-37d-mm-metal-gearmotors-no-gearbox-helical-pinion.html.md))

This is the motor and encoder portion of our 24V 37D mm metal gearmotors with 64 CPR encoders. It does not include a gearbox, but the pinion gear on the output shaft works with all of our helical pinion 37D mm gearmotor gearboxes, so this can be used as a replacement motor or encoder for those gearboxes.

## Pricing

- **Price:** $89.30 (inc GST) — $81.18 AUD, exc GST
- **Quantity discounts:** 6+ $77.94 (exc GST) · 12+ $75.50 (exc GST)

## Availability & dispatch

- Available with a lead time — expect dispatch between Aug 17 and Aug 18.

## Description

This 24 V motor with integrated 64 CPR (counts per revolution) quadrature encoder is intended as a replacement motor and encoder for Pololu's [24V 37D mm metal gearmotors](https://core-electronics.com.au/category/272/24v-37d-metal-gearmotors) **with helical pinion gears**.

| \| [![](https://core-electronics.com.au/attachments/localcontent/0J10762_233582dc8e4.jpg)](https://core-electronics.com.au/attachments/localcontent/0J10762_244431e854e.jpg) \| \|---\| | \| [![](https://core-electronics.com.au/attachments/localcontent/0J10764_18026c2da62.jpg)](https://core-electronics.com.au/attachments/localcontent/0J10764_20857d2d15e.jpg) \| \|---\|---\| |
|---|

The 2mm output shaft has a non-removable pinion gear that works with all of Pololu's “Helical Pinion” 37D mm gearmotor gearboxes. Note that Pololu do not sell the 37D 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.

| [![](https://core-electronics.com.au/attachments/localcontent/0J10505_319988840f1.jpg)](https://core-electronics.com.au/attachments/localcontent/0J10505_40313accb92.jpg) |
|---|
| 37D Gearmotor (Helical Pinion) with the gearbox removed showing the helical pinion gear and first mating gear. |

**Dimensions**

| [![](https://core-electronics.com.au/attachments/localcontent/0J10759_96274ed1271.jpg)](https://core-electronics.com.au/attachments/localcontent/0J10759_173749a4aac.jpg) |
|---|
| Dimensions of the Motor with 64 CPR Encoder for 37D mm Metal Gearmotors (No Gearbox, Helical Pinion). Units are mm over \[inches\]. |

This diagram is also available as a **downloadable PDF** (459k pdf).

**Warning**: Do not screw too far into the mounting holes as the screws damage the motor. Pololu recommend screwing no more than 3.5mm (0.14") into the screw hole.

**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). Pololu's 37D mm line of 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 | Stall Current | No-Load Current | Gear Ratio | No-Load Speed (RPM) | Extrapolated Stall Torque | Max Power (W) | ![](https://core-electronics.com.au/attachments/localcontent/0J10680_2698f90938.jpg)  Without Encoder | ![](https://core-electronics.com.au/attachments/localcontent/0J10683_5898597341.jpg)  With Encoder |
|---|---|---|---|---|---|---|---|---|
| (kg · cm) | (oz · in) |
|  |
|  |
| 12 V | 5.5 A | 0.2 A | 1:1 (no gearbox) | 10,000 | 0.5 | 7 | – | – | [item #4750](https://core-electronics.com.au/12v-motor-with-64-cpr-encoder-for-37d-mm-metal-gearmotors-no-gearbox-helical-pinion.html) |
| 6.3:1 | 1600 | 3.0 | 42 | 12 | [item #4747](https://core-electronics.com.au/6-3-1-metal-gearmotor-37dx50l-mm-12v-helical-pinion.html) | [item #4757](https://core-electronics.com.au/6-3-1-metal-gearmotor-37dx65l-mm-12v-with-64-cpr-encoder-helical-pinion.html) |
| 10:1 | 1000 | 4.9 | 68 | 12 | [item #4748](https://core-electronics.com.au/10-1-metal-gearmotor-37dx50l-mm-12v-helical-pinion.html) | [item #4758](https://core-electronics.com.au/10-1-metal-gearmotor-37dx65l-mm-12v-with-64-cpr-encoder-helical-pinion.html) |
| 19:1 | 530 | 8.5 | 120 | 12 | [item #4741](https://core-electronics.com.au/pololu-19-1-metal-gearmotor-37dx52l-mm-helical-pinion.html) | [item #4751](https://core-electronics.com.au/19-1-metal-gearmotor-37dx68l-mm-12v-with-64-cpr-encoder-helical-pinion.html) |
| 30:1 | 330 | 14 | 190 | 12 | [item #4742](https://core-electronics.com.au/pololu-metal-gearmotor-30-1-37dx52l-mm-helical-pinion.html) | [item #4752](https://core-electronics.com.au/30-1-metal-gearmotor-37dx68l-mm-with-64-cpr-encoder-helical-pinion.html) |
| 50:1 | 200 | 21 | 290 | 10 | [item #4743](https://core-electronics.com.au/50-1-metal-gearmotor-37dx54l-mm-12v-helical-pinion.html) | [item #4753](https://core-electronics.com.au/50-1-metal-gearmotor-37dx70l-mm-12v-with-64-cpr-encoder-helical-pinion.html) |
| 70:1 | 150 | 27 | 380 | 10\* | [item #4744](https://core-electronics.com.au/70-1-metal-gearmotor-37dx54l-mm-12v-helical-pinion.html) | [item #4754](https://core-electronics.com.au/70-1-metal-gearmotor-37dx70l-mm-12v-with-64-cpr-encoder-helical-pinion.html) |
| 100:1 | 100 | 34 | 470 | 8\* | [item #4745](https://core-electronics.com.au/100-1-metal-gearmotor-37dx57l-mm.html) | [item #4755](https://core-electronics.com.au/100-1-metal-gearmotor-37dx73l-mm-12v-with-64-cpr-encoder-helical-pinion.html) |
| 131:1 | 76 | 45 | 630 | 6\* | [item #4746](https://core-electronics.com.au/131-1-metal-gearmotor-37dx57l-mm-12v-helical-pinion.html) | [item #4756](https://core-electronics.com.au/131-1-metal-gearmotor-37dx73l-mm-12v-with-64-cpr-encoder-helical-pinion.html) |
| 150:1 | 67 | 49 | 680 | 6\* | [item #2829](https://core-electronics.com.au/150-1-metal-gearmotor-37dx57l-mm-12v-helical-pinion.html) | [item #2828](https://core-electronics.com.au/150-1-metal-gearmotor-37dx73l-mm-12v-with-64-cpr-encoder-helical-pinion.html) |
|  |
|  |
| 24 V | 3 A | 0.1 A | 1:1 (no gearbox) | 10,000 | 0.55 | 8 | – | – | [item #4690](https://core-electronics.com.au/24v-motor-with-64-cpr-encoder-for-37d-mm-metal-gearmotors-no-gearbox-helical-pinion.html) |
| 6.3:1 | 1600 | 3.5 | 49 | 14 | [item #4688](https://core-electronics.com.au/6-3-1-metal-gearmotor-37dx50l-mm-24v-helical-pinion.html) | [item #4698](https://core-electronics.com.au/6-3-1-metal-gearmotor-37dx65l-mm-24v-with-64-cpr-encoder-helical-pinion.html) |
| 10:1 | 1000 | 5.5 | 76 | 14 | [item #4689](https://core-electronics.com.au/10-1-metal-gearmotor-37dx50l-mm-24v-helical-pinion.html) | [item #4699](https://core-electronics.com.au/10-1-metal-gearmotor-37dx65l-mm-24v-with-64-cpr-encoder-helical-pinion.html) |
| 19:1 | 530 | 9.5 | 130 | 13 | [item #4681](https://core-electronics.com.au/10-1-metal-gearmotor-37dx50l-mm-24v-helical-pinion-47214.html) | [item #4691](https://core-electronics.com.au/19-1-metal-gearmotor-37dx68l-mm-24v-with-64-cpr-encoder-helical-pinion.html) |
| 30:1 | 330 | 15 | 210 | 13 | [item #4682](https://core-electronics.com.au/30-1-metal-gearmotor-37dx52l-mm-24v-helical-pinion.html) | [item #4692](https://core-electronics.com.au/30-1-metal-gearmotor-37dx68l-mm-24v-with-64-cpr-encoder-helical-pinion.html) |
| 50:1 | 200 | 23 | 320 | 12 | [item #4683](https://core-electronics.com.au/50-1-metal-gearmotor-37dx54l-mm-24v-helical-pinion.html) | [item #4693](https://core-electronics.com.au/50-1-metal-gearmotor-37dx70l-mm-24v-with-64-cpr-encoder-helical-pinion.html) |
| 70:1 | 140 | 31 | 430 | 10\* | [item #4684](https://core-electronics.com.au/70-1-metal-gearmotor-37dx54l-mm-24v-helical-pinion.html) | [item #4694](https://core-electronics.com.au/70-1-metal-gearmotor-37dx70l-mm-24v-with-64-cpr-encoder-helical-pinion.html) |
| 100:1 | 100 | 39 | 540 | 8\* | [item #4685](https://core-electronics.com.au/100-1-metal-gearmotor-37dx57l-mm-24v-helical-pinion.html) | [item #4695](https://core-electronics.com.au/100-1-metal-gearmotor-37dx73l-mm-24v-with-64-cpr-encoder-helical-pinion.html) |
| 131:1 | 79 | 47 | 650 | 6\* | [item #4686](https://core-electronics.com.au/131-1-metal-gearmotor-37dx57l-mm-24v-helical-pinion.html) | [item #4696](https://core-electronics.com.au/131-1-metal-gearmotor-37dx73l-mm-24v-with-64-cpr-encoder-helical-pinion.html) |
| 150:1 | 68 | 56 | 780 | 6\* | [item #4687](https://core-electronics.com.au/150-1-metal-gearmotor-37dx57l-mm-24v-helical-pinion.html) | [item #4697](https://core-electronics.com.au/150-1-metal-gearmotor-37dx73l-mm-24v-with-64-cpr-encoder-helical-pinion.html) |
|  |
| \* Output power for these units is constrained by gearbox load limits; spec provided is output power at max recommended load of 10 kg·cm. |

**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 10 kg-cm (150 oz-in), and the recommended upper limit for instantaneous torque is 25 kg-cm (350 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.

This motor is intended for use at 24 V, though in general, these kinds of motors can run at voltages above and below the nominal voltage; lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor.

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 can be seen in the pictures below that show this motor combined with a gearbox:

| \| [![](https://core-electronics.com.au/attachments/localcontent/0J6851_11827267703.jpg)](https://core-electronics.com.au/attachments/localcontent/0J6851_16075dad91e.jpg) \| \|---\| | \| [![](https://core-electronics.com.au/attachments/localcontent/0J6853_823601d594.jpg)](https://core-electronics.com.au/attachments/localcontent/0J6853_25209597182.jpg) \| \|---\|---\| |
|---|

| [![](https://core-electronics.com.au/attachments/localcontent/0J6852_226863d84ee.jpg)](https://core-electronics.com.au/attachments/localcontent/0J6852_337891a74ed.jpg) |
|---|
| 37D mm metal gearmotor with 64 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 64 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 64. The motor/encoder has six color-coded, 8" (20 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 12 V motor at 12 V and a Hall sensor Vcc of 5 V:

| ![](https://core-electronics.com.au/attachments/localcontent/0J2643_78337a09d37.jpg) |
|---|
| Encoder A and B outputs for 37D mm metal gearmotor with 64 CPR encoder (12V motor running at 12 V). |

By counting both the rising and falling edges of both the A and B outputs, it is possible to get 64 counts per revolution of the motor shaft. Using just a single edge of one channel results in 16 counts per revolution of the motor shaft, so the frequency of the A output in the above oscilloscope capture is 16 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: | 34.5D × 46.5L mm[1](https://core-electronics.com.au/#note1) |
|---|---|
| Weight: | 110 g |

**General specifications**

 | Gear ratio: | 1:1[2](https://core-electronics.com.au/#note2) |
|---|---|
| No-load speed @ 24V: | 10000 rpm |
| No-load current @ 24V: | 0.1 A |
| Stall current @ 24V: | 3 A[3](https://core-electronics.com.au/#note3) |
| Stall torque @ 24V: | 0.55 kg·cm[3](https://core-electronics.com.au/#note3) |
| No-load speed @ 12V: | 5000 rpm[4](https://core-electronics.com.au/#note4) |
| No-load current @ 12V: | 0.08 A[4](https://core-electronics.com.au/#note4) |
| Stall current @ 12V: | 1.7 A[4](https://core-electronics.com.au/#note4) |
| Stall torque @ 12V: | 0.3 kg·cm[4](https://core-electronics.com.au/#note4) |
| Motor type: | 24V |
| Lead length: | 20 cm[5](https://core-electronics.com.au/#note5) |
| Encoders?: | Y |
| Encoder resolution: | 64 CPR |

**Notes:**

1Length measurement does not include motor shaft or pinion gear.2This motor does not have a gearbox.3Stalling can 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.4This motor will run at 12 V but is intended for operation at 24 V.5May vary by a few centimeters. **File downloads**

- **Datasheet for Pololu 37D Metal Gearmotors (2MB pdf)**
- **Dimension diagrams of the Pololu 37D mm Metal Gearmotors (459k pdf)**
- **3D models of 37D mm gearmotors (7MB zip)**
    
    This file contains 3D models (in the step file format) of the 37D mm gearmotors with and without encoders.
 
**Recommended links**

- **[MATLAB script to plot motor performance curves for Pololu brushed DC gearmotors](https://www.mathworks.com/matlabcentral/fileexchange/54695-polulu-motor-plot-generator)**
    
    This MATLAB script, written by Ali Asgher Mansoor Habiby, plots speed, power, current draw, and efficiency as they vary with torque when you input the gearmotor specifications. It also prints the resistance of the motor, and the current draw and torque at which maximum efficiency and maximum power occur.

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/0/j/0j10762.1200.jpg)