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Pololu 2280 - Motor with 48 CPR Encoder for 25D mm Metal Gearmotors (No Gearbox) View larger

Pololu 2280 - Motor with 48 CPR Encoder for 25D mm Metal Gearmotors (No Gearbox)

Motor with 48 CPR Encoder for 25D mm Metal Gearmotors (No Gearbox)

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ID: 210494

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Data sheet

Engine size (series)Other
DC motor powerLP
Gear materialBrak przekładni
Gear ratioBrak przekładni
Rotation speed6200RPM
Shaft shapeRound
Power supply voltage6V

More info

Motor with 48 CPR Encoder for 25D mm Metal Gearmotors (No Gearbox)

This is the motor and encoder portion of the low-power (non-HP) versions of our 25D mm metal gearmotors with 48 CPR encoders. It does not include a gearbox, but the pinion gear on the output shaft works with all of our 25D mm gearmotor gearboxes, so this can be used as a replacement motor or encoder for those gearboxes. It is intended for use at 6 V, though it should operate comfortably in the 3 V to 9 V range.

Key specs at 6 V: 5600 RPM and 80 mA free-run, 1 oz-in (0.07 kg-cm) and 2.2 A stall.


This motor with integrated 48 CPR (counts per revolution) quadrature encoder is intended as a replacement low-power (non-HP) motor and encoder for our 25D mm metal gearmotors. The output shaft has a non-removable pinion gear that works with all of our 25D mm gearmotor gearboxes. Note that we 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 6.5 mm.

A higher-power motor with encoder with identical dimensions and an identical pinion gear is also available.

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). Our 25D mm line of metal gearmotors consist of this non-HP motor or an HP motor combined with different gearboxes. We 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, we strongly recommend you consider getting a preassembled gearmotor with the gear ratio that best suits your project requirements.

Gear RatioNo-Load
@ 6 V
Stall Torque
@ 6 V
Stall Current
@ 6 V

With Encoder

Without Encoder
1:19800 RPM2 oz-in6 Amotor without gearbox
5600 RPM1 oz-in2.2 Amotor without gearbox
4.4:12220 RPM8 oz-in6 A25Dx48L mm HP
1280 RPM5 oz-in2.2 A25Dx48L mm
9.7:11010 RPM17 oz-in6 A25Dx48L mm HP25Dx48L mm HP
580 RPM11 oz-in2.2 A25Dx48L mm25Dx48L mm
20.4:1480 RPM36 oz-in6 A25Dx50L mm HP
275 RPM24 oz-in2.2 A25Dx50L mm
34:1285 RPM60 oz-in6 A25Dx52L mm HP25Dx52L mm HP
165 RPM40 oz-in2.2 A25Dx52L mm25Dx52L mm
47:1210 RPM80 oz-in6 A25Dx52L mm HP25Dx52L mm HP
120 RPM50 oz-in2.2 A25Dx52L mm25Dx52L mm
75:1130 RPM130 oz-in6 A25Dx54L mm HP25Dx54L mm HP
75 RPM85 oz-in2.2 A25Dx54L mm25Dx54L mm
99:1100 RPM160 oz-in6 A25Dx54L mm HP
57 RPM110 oz-in2.2 A25Dx54L mm
172:157 RPM260 oz-in6 A25Dx56L mm HP
33 RPM170 oz-in2.2 A25Dx56L mm25Dx56L mm
227:125 RPM220 oz-in2.2 A25Dx56L mm
378:115 RPM250 oz-in2.2 A25Dx58L mm
499:112 RPM300 oz-in2.2 A25Dx58L mm

Note: At some of the higher gear ratios, these motors can generate enough torque to damage themselves. Any torque greater than about 250 oz-in (18 kg-cm) is likely to damage the gearbox, so we recommend that you avoid stalling the 172:1 HP, 227:1, 378:1, and 499:1 versions of these motors at 6 V.

These motors are intended for use at 6 V. In general, these kinds of motors can run at voltages above and below this nominal voltage, so they should comfortably operate in the 3 – 9 V range, though they can begin rotating at voltages as low as 1 V. Higher voltages could start negatively affecting the life of the motor.

25D mm metal gearmotor with 48 CPR encoder: close-up view of encoder.

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 and our male jumper and precrimped wires. 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:

Redmotor power (connects to one motor terminal)
Blackmotor power (connects to the other motor terminal)
Greenencoder GND
Blueencoder Vcc (3.5 – 20 V)
Yellowencoder A output
Whiteencoder 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:

Encoder A and B outputs for 25D mm (non-HP) 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

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.

Some of the Pololu metal gearmotors.