This tiny, cylindrical gearmotor consists of a coreless brushed DC motor and a 136:1 plastic planetary gearbox. The entire assembly has a diameter of just 6 mm (0.24″) and an extremely light weight of 1.25 g (0.044 oz), making it a great actuator for miniature robots and very small mechanisms.Key specs at 6 V: 500 RPM and 45 mA free-run, 8 oz-in (0.6 kg-cm) and 400 mA stall.

26:1 sub-micro plastic planetary gearmotor next to a micro metal gearmotor and a LEGO Minifigure for size reference.

Sub-micro plastic planetary gearmotors. Gear ratios from top to bottom: 700:1, 136:1, 26:1.

These tiny brushed DC gearmotors have a diameter of just 6 mm and weigh just over a gram, which makes them great actuators for miniature robots and very small mechanisms. They consist of a coreless motor fastened to a planetary gearbox by a small clip. The gears are made from liquid crystal polymers (LCPs), and gearbox’s nylon output shaft is compatible with our 14 mm wheels. Three gear ratios are available:

26:1, which has a free run speed of 2500 RPM and stall torque of 1.5 oz-in (110 g-cm) at 6 V

136:1, which has a free run speed of 500 RPM and stall torque of 8 oz-in (550 g-cm) at 6 V

700:1, which has a free run speed of 90 RPM and stall torque of 12 oz-in (900 g-cm) at 6 V

Note: Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. For these gearboxes, the recommended upper limit for instantaneous torque is 3.5 oz-in (250 g-cm); we strongly advise keeping applied loads well under this limit. 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.

The intended nominal operating voltage for these motors is 3 V to 6 V, though in general, these kinds of motors can be used at voltages outside this range (rotation typically starts between 0.2 V and 0.3 V). Lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor. When operating at 3 V, the free-run speed, stall torque, and stall current will all be approximately half of what they are at 6 V as these specifications scale roughly linearly with voltage.

Since the gearmotor’s output shaft is nylon, there can be small variances in the diameter from unit to unit. These variations might cause press-fit attachments like our 14 mm wheel to fit loosely in some instances. If you experience a loose fit, you could try swapping wheels or using a small dab of glue to help hold the wheel on.

The following diagram shows the micro plastic gearmotor dimensions in mm. The planetary gearbox has a D-shaped plastic output shaft, which is 2 mm in diameter with a section that is flattened by 0.5 mm. The “D” portion of the shaft is 2.5 mm long. The motor measures 6 mm in diameter and 9.3 mm in length, and the gearbox length, labeled “L” in the diagram below, depends on the gear ratio.

Dimensions of the Sub-Micro Plastic Planetary Gearmotors. Units are mm over [inches].

This dimension diagram is also available as a downloadable PDF (92k pdf).

These motors originally shipped with leads that extended approximately 2 cm (0.8″) from the back of the motor, but we began transitioning to shipping units with much longer leads (approximately 12.5 cm, or 5″) in January, 2017. These leads are pre-stripped and unterminated (i.e. they do not end in a connector).

The micro plastic gearmotor’s output shaft is compatible with our 14 mm wheels. We do not have any brackets for this gearmotor, and it does not have any mounting holes, but its compact size makes it easy to fasten with tape or glue. Alternatively, since this gearmotor is nearly the same size as a 1/4″ fuse, it can be mounted using standard 1/4″ (6 mm) fuse clips, which can be found at places like Radio Shack and Digi-Key.

Sub-micro plastic planetary gearmotor with a 14×4.5mm wheel.

26:1 sub-micro plastic planetary gearmotor being held by a 1/4″ (6 mm) fuse clip.

People often buy this product together with:

This gearmotor consists of a low-power, 6 V brushed DC motor combined with a 98.78:1 metal spur gearbox, and it has an integrated 48 CPR quadrature encoder on the motor shaft, which provides 4741.44 counts per revolution of the gearbox’s output shaft. The gearmotor is cylindrical, with a diameter just under 25 mm, and the D-shaped output shaft is 4 mm in diameter and extends 12.5 mm from the face plate of the gearbox.Key specs at 6 V: 58 RPM and 250 mA free-run, 130 oz-in (9.4 kg-cm) and 2.4 A stall.

These cylindrical brushed DC gearmotors are available in a wide range of gear ratios and with five different motors (two power levels of 6V motors and three power levels of 12V 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). All versions are also available with an integrated 48 CPR quadrature encoder on the motor shaft. Please see the 25D metal gearmotor comparison table for detailed specifications of all our 25D metal gearmotors. This dynamically-sortable table can help you find the gearmotor that offers the best blend of speed, torque, and current-draw for your particular application. A more basic comparison table is available below:

Note: Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. For these gearboxes, the recommended upper limit for instantaneous torque is 200 oz-in (15 kg-cm); we strongly advise keeping applied loads well under this limit. Stalls can also result in rapid (potentially on the order of a second) thermal damage to the motor windings and brushes, especially for the versions that use high-power (HP) motors; 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; lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor.

Exact gear ratio: ``(22×22×22×22×22×23) / (12×10×10×10×10×10) ~~bb(98.78:1)``

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 (223k pdf).

Dimensions of the Pololu 25D mm metal gearmotors. Units are mm over [inches].

The face plate has two mounting holes threaded for M3 screws. You can use our 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.

Pololu 25D mm metal gearmotor bracket pair.

Pololu 25D mm gearmotor with bracket.

The 4 mm 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 as shown in the left picture below. Alternatively, you could use our 4mm scooter wheel adapter to mount many common scooter, skateboard, and inline skate wheels to the gearmotor’s output shaft as shown in the right picture below.

Pololu 60×8mm wheel on a Pololu 25D mm metal gearmotor.

A 25D mm gearmotor connected to a scooter wheel by the 4 mm scooter wheel adapter.

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 (the left picture below shows a 25D mm gearmotor while the right picture shows the smaller 20D mm gearmotor):

Dagu Wild Thumper wheel 120×60mm (chrome) with Pololu 25D mm metal gearmotor.

Dagu Wild Thumper wheel 120×60mm (metallic red) with Pololu 20D mm metal gearmotor.

12mm Hex Wheel Adapter for 4mm Shaft on a 20D mm Metal Gearmotor.

We have a number of motor controllers and motor drivers that work with these 25D mm metal gearmotors. For the LP and MP versions, we recommend our MC33296-based motor drivers, for which we have basic single and dual carriers and a dual-channel shield for Arduino. For the HP versions, we recommend our VNH5019-based motor drivers (available as single and dual carriers), though these can also be a good choice for the lower-power motors because they will run much cooler than the MC33926 carriers. If you are looking for higher-level control interfaces, such as USB, RC, analog voltages, or TTL serial, consider our Simple Motor Controllers, Jrk motor controllers, or TReX 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).

Pololu dual VNH5019 motor driver shield for Arduino.

Pololu TReX Dual Motor Controller.

Simple Motor Controller 18v7, fully assembled.

We have an assortment of Hall effect-based current sensors to choose from for those who need to monitor motor current:

ACS711EX current sensor carrier -15.5A to +15.5A.

ACS714 current sensor carrier -5A to +5A.

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

The versions of these gearmotors with encoders use a A two-channel Hall effect sensor to detect 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, 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 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:

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 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.

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.

People often buy this product together with:

This 200:1 gearbox with brushed DC motor has a low-current motor and provides power and speed that is comparable to an RC servo at a fraction of the cost. At 6 V, it has a free-run speed of 51 RPM and a stall torque of approximately 100 oz-in. Though the product picture shows two gearmotors, this product is for a single motor.

Pololu plastic gearmotor 90 deg. output with opened gearbox.

This 200:1 plastic gearmotor (gearbox with brushed DC motor) is a great low-cost alternative to modified hobby servos or Tamiya gearboxes. The low-current motor is a perfect match for our qik 2s9v1 dual serial motor controller, Baby Orangutan robot controller, or DRV8833 dual motor driver carrier, and the compact size makes this unit an attractive choice for small robot designs. The recommended operating voltage range for this motor is 3 – 12 V.

This is a higher-torque, lower-speed version of the 120:1 plastic gearmotor 90-degree output. At 6 V, the gearbox and motor provide approximately 100 oz-in of torque and 51 RPM. The free-running current is 70 mA, and the stall current is 800 mA. The gearbox is protected by a built-in safety clutch that will typically slip before gear teeth can shear.

This gearmotor comes pre-assembled, with the gears fully enclosed, and the output shaft is 6 mm long and 7 mm in diameter with two sides flattened. The output shaft is at a 90° angle from the axis of the motor shaft; we also sell a similar gearmotor with an offset output shaft.

There are two built-in mounting holes that work with our stamped aluminum L-bracket and extended stamped aluminum L-bracket, as shown in the pictures below:

Plastic gearmotor with 90-degree output (item #1120 or #1121) mounted with Pololu stamped aluminum L-bracket.

Plastic gearmotor with 90-degree output (item #1120 or #1121) mounted with Pololu extended stamped aluminum L-bracket.

A custom-molded GMPW plastic wheel for this gearmotor is available in a variety of colors.

Dimensions (in mm) of the 120:1 and 200:1 plastic gearmotors with 90-degree outputs.

You can download a pdf version of this drawing here (104k pdf).

People often buy this product together with:

This gearmotor is a miniature low-power, 6 V brushed DC motor with a 9.96:1 metal gearbox. It has a cross section of 10 × 12 mm, and the D-shaped gearbox output shaft is 9 mm long and 3 mm in diameter.Key specs at 6 V: 1300 RPM and 40 mA with no load, 2 oz-in (0.2 kg-cm) and 0.36 A at stall.

These tiny brushed DC gearmotors are available in a wide range of gear ratios—from 5:1 up to 1000:1—and with five different motors: high-power 6 V and 12 V motors with long-life carbon brushes (HPCB), and high-power (HP), medium power (MP), and low power (LP) 6 V motors with shorter-life precious metal brushes. The 6 V and 12 V HPCB motors offer the same performance at their respective nominal voltages, just with the 12 V motor drawing half the current of the 6 V motor. The 6 V HPCB and 6 V HP motors are identical except for their brushes, which only affect the lifetime of the motor.

The HPCB versions (shown on the left in the picture below) can be differentiated from versions with precious metal brushes (shown on the right) by their copper-colored terminals. Note that the HPCB terminals are 0.5 mm wider than those on the other micro metal gearmotor versions (2 mm vs. 1.5 mm), and they are about 1 mm closer together (6 mm vs. 7 mm).

Versions of these gearmotors are also available with an additional 1 mm-diameter output shaft that protrudes from the rear of the motor. This 4.5 mm-long rear shaft rotates at the same speed as the input to the gearbox and offers a way to add an encoder, such as our magnetic encoder for micro metal gearmotors (see the picture on the right), to provide motor speed or position feedback.

With the exception of the 1000:1 gear ratio versions, all of the micro metal gearmotors have the same physical dimensions, so one version can be easily swapped for another if your design requirements change.

Please see the micro metal gearmotor datasheet (2MB pdf) for more information, including detailed performance graphs for each micro metal gearmotor version. You can also use our dynamically sortable micro metal gearmotor comparison table for search for the gearmotor that offers the best blend of speed, torque, and current-draw for your particular application. A more basic comparison table is available below.

Note: Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. The recommended upper limit for instantaneous torque is 35 oz-in (2.5 kg-cm) for the 1000:1 gearboxes and 25 oz-in (2 kg*cm) for all the other gear ratios; we strongly advise keeping applied loads well under this limit. Stalls can also result in rapid (potentially on the order of seconds) thermal damage to the motor windings and brushes, especially for the versions that use high-power (HP and HPCB) motors; 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; lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor.

Exact gear ratio: ``(35×37) / (13×10) ~~ bb(9.96:1)``

In terms of size, these gearmotors are very similar to Sanyo’s popular 12 mm NA4S DC gearmotors, and gearmotors with this form factor are occasionally referred to as N20 motors. The versions with carbon brushes (HPCB) have slightly different terminal and end-cap dimensions than the versions with precious metal brushes, but all of the other dimensions are identical.

Dimensions of versions with carbon brushes (HPCB)

Dimensions of the Pololu micro metal gearmotors with carbon brushes (HPCB). Units are mm over [inches].

Dimensions of versions with precious metal brushes (LP, MP, and HP)

Dimensions of the Pololu micro metal gearmotors with precious metal brushes: low-power (LP), medium-power (MP), and high-power (HP). Units are mm over [inches].

These diagrams are also available as a downloadable PDF (262k pdf).

Wheels and hubs: The micro metal gearmotor’s output shaft matches our assortment of Pololu wheels and the Solarbotics RW2i rubber wheel. You can also use our Pololu universal mounting hubs to mount custom wheels and mechanism to the micro metal gearmotor’s output shaft, and you can use our 12mm hex wheel adapter to use this motor with many common hobby RC wheels.

Pololu wheel 32×7mm on a micro metal gearmotor.

Black Pololu 70×8mm wheel on a Pololu micro metal gearmotor.

A pair of Pololu universal aluminum mounting hubs for 3 mm diameter shafts.

12mm Hex Wheel Adapter for 3mm Shaft on a Micro Metal Gearmotor.

Mounting brackets: Our mounting bracket (also available in white) and extended mounting bracket are specifically designed to securely mount the gearmotor while enclosing the exposed gears. We recommend the extended mounting bracket for wheels with recessed hubs, such as the Pololu wheel 42×19mm. Our micro metal gearmotors will also work with our 15.5D mm metal gearmotor bracket pair.

Black micro metal gearmotor mounting bracket pair with included screws and nuts.

White micro metal gearmotor mounting bracket pair with included screws and nuts.

Pololu micro metal gearmotor bracket extended with micro metal gearmotor.

Quadrature encoders: We offer several quadrature encoders that work with our micro metal gearmotors.

Magnetic Encoder Kit for Micro Metal Gearmotors assembled with ribbon cable wires.

Example of an installed micro metal gearmotor reflective optical encoder.

Note: The HPCB versions of our micro metal gearmotors are not compatible with our #2590 and #2591 optical encoders or our older #2598 magnetic encoders (the terminals are too wide to fit through the corresponding holes in the encoder boards). However, they are compatible with our newer #3081 magnetic encoders.

Motor controllers and drivers: We have a number of motor controllers, motor drivers, and robot controllers that make it easy to drive these micro metal gearmotors. For the 6 V micro metal gearmotors, consider the DRV8838 single-channel motor driver carrier, the DRV8833 dual motor driver carrier, and DRV8835 dual motor driver carrier (or DRV8835 shield for Arduino). For the 12 V micro metal gearmotors, consider the MAX14870 single-channel motor driver carrier, DRV8801 single-channel motor driver carrier, and A4990 dual motor driver carrier (or A4990 shield for Arduino).

DRV8838 Single Brushed DC Motor Driver Carrier.

Pololu A4990 Dual Motor Driver Shield for Arduino, bottom view.

DRV8835 dual motor driver carrier.

Current sensors: We have an assortment of Hall effect-based current sensors to choose from for those who need to monitor motor current:

ACS711EX current sensor carrier -15.5A to +15.5A.

ACS714 current sensor carrier -5A to +5A.

We also incorporate these motors into some of our products, including our Zumo robot and 3pi robot :

Assembled Zumo 32U4 robot.

Pololu 3pi robot.

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.

People often buy this product together with:

This gearmotor is a miniature low-power, 6 V brushed DC motor with a 100.37:1 metal gearbox. It has a cross section of 10 × 12 mm, and the D-shaped gearbox output shaft is 9 mm long and 3 mm in diameter.Key specs at 6 V: 120 RPM and 40 mA with no load, 12 oz-in (0.9 kg-cm) and 0.36 A at stall.

These tiny brushed DC gearmotors are available in a wide range of gear ratios—from 5:1 up to 1000:1—and with five different motors: high-power 6 V and 12 V motors with long-life carbon brushes (HPCB), and high-power (HP), medium power (MP), and low power (LP) 6 V motors with shorter-life precious metal brushes. The 6 V and 12 V HPCB motors offer the same performance at their respective nominal voltages, just with the 12 V motor drawing half the current of the 6 V motor. The 6 V HPCB and 6 V HP motors are identical except for their brushes, which only affect the lifetime of the motor.

The HPCB versions (shown on the left in the picture below) can be differentiated from versions with precious metal brushes (shown on the right) by their copper-colored terminals. Note that the HPCB terminals are 0.5 mm wider than those on the other micro metal gearmotor versions (2 mm vs. 1.5 mm), and they are about 1 mm closer together (6 mm vs. 7 mm).

Versions of these gearmotors are also available with an additional 1 mm-diameter output shaft that protrudes from the rear of the motor. This 4.5 mm-long rear shaft rotates at the same speed as the input to the gearbox and offers a way to add an encoder, such as our magnetic encoder for micro metal gearmotors (see the picture on the right), to provide motor speed or position feedback.

With the exception of the 1000:1 gear ratio versions, all of the micro metal gearmotors have the same physical dimensions, so one version can be easily swapped for another if your design requirements change.

Please see the micro metal gearmotor datasheet (2MB pdf) for more information, including detailed performance graphs for each micro metal gearmotor version. You can also use our dynamically sortable micro metal gearmotor comparison table for search for the gearmotor that offers the best blend of speed, torque, and current-draw for your particular application. A more basic comparison table is available below.

Note: Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. The recommended upper limit for instantaneous torque is 35 oz-in (2.5 kg-cm) for the 1000:1 gearboxes and 25 oz-in (2 kg*cm) for all the other gear ratios; we strongly advise keeping applied loads well under this limit. Stalls can also result in rapid (potentially on the order of seconds) thermal damage to the motor windings and brushes, especially for the versions that use high-power (HP and HPCB) motors; 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; lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor.

Exact gear ratio: ``(35×37×35×38) / (12×11×13×10) ~~ bb(100.37:1)``

In terms of size, these gearmotors are very similar to Sanyo’s popular 12 mm NA4S DC gearmotors, and gearmotors with this form factor are occasionally referred to as N20 motors. The versions with carbon brushes (HPCB) have slightly different terminal and end-cap dimensions than the versions with precious metal brushes, but all of the other dimensions are identical.

Dimensions of versions with carbon brushes (HPCB)

Dimensions of the Pololu micro metal gearmotors with carbon brushes (HPCB). Units are mm over [inches].

Dimensions of versions with precious metal brushes (LP, MP, and HP)

Dimensions of the Pololu micro metal gearmotors with precious metal brushes: low-power (LP), medium-power (MP), and high-power (HP). Units are mm over [inches].

These diagrams are also available as a downloadable PDF (262k pdf).

Wheels and hubs: The micro metal gearmotor’s output shaft matches our assortment of Pololu wheels and the Solarbotics RW2i rubber wheel. You can also use our Pololu universal mounting hubs to mount custom wheels and mechanism to the micro metal gearmotor’s output shaft, and you can use our 12mm hex wheel adapter to use this motor with many common hobby RC wheels.

Pololu wheel 32×7mm on a micro metal gearmotor.

Black Pololu 70×8mm wheel on a Pololu micro metal gearmotor.

A pair of Pololu universal aluminum mounting hubs for 3 mm diameter shafts.

12mm Hex Wheel Adapter for 3mm Shaft on a Micro Metal Gearmotor.

Mounting brackets: Our mounting bracket (also available in white) and extended mounting bracket are specifically designed to securely mount the gearmotor while enclosing the exposed gears. We recommend the extended mounting bracket for wheels with recessed hubs, such as the Pololu wheel 42×19mm. Our micro metal gearmotors will also work with our 15.5D mm metal gearmotor bracket pair.

Black micro metal gearmotor mounting bracket pair with included screws and nuts.

White micro metal gearmotor mounting bracket pair with included screws and nuts.

Pololu micro metal gearmotor bracket extended with micro metal gearmotor.

Quadrature encoders: We offer several quadrature encoders that work with our micro metal gearmotors.

Magnetic Encoder Kit for Micro Metal Gearmotors assembled with ribbon cable wires.

Example of an installed micro metal gearmotor reflective optical encoder.

Note: The HPCB versions of our micro metal gearmotors are not compatible with our #2590 and #2591 optical encoders or our older #2598 magnetic encoders (the terminals are too wide to fit through the corresponding holes in the encoder boards). However, they are compatible with our newer #3081 magnetic encoders.

Motor controllers and drivers: We have a number of motor controllers, motor drivers, and robot controllers that make it easy to drive these micro metal gearmotors. For the 6 V micro metal gearmotors, consider the DRV8838 single-channel motor driver carrier, the DRV8833 dual motor driver carrier, and DRV8835 dual motor driver carrier (or DRV8835 shield for Arduino). For the 12 V micro metal gearmotors, consider the MAX14870 single-channel motor driver carrier, DRV8801 single-channel motor driver carrier, and A4990 dual motor driver carrier (or A4990 shield for Arduino).

DRV8838 Single Brushed DC Motor Driver Carrier.

Pololu A4990 Dual Motor Driver Shield for Arduino, bottom view.

DRV8835 dual motor driver carrier.

Current sensors: We have an assortment of Hall effect-based current sensors to choose from for those who need to monitor motor current:

ACS711EX current sensor carrier -15.5A to +15.5A.

ACS714 current sensor carrier -5A to +5A.

We also incorporate these motors into some of our products, including our Zumo robot and 3pi robot :

Assembled Zumo 32U4 robot.

Pololu 3pi robot.

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.

People often buy this product together with:

This gearmotor is a miniature high-power, 6 V brushed DC motor with a 100.37:1 metal gearbox. It has a cross section of 10 × 12 mm, and the D-shaped gearbox output shaft is 9 mm long and 3 mm in diameter. This version also has a 4.5 × 1 mm extended motor shaft.Key specs at 6 V: 320 RPM and 120 mA with no load, 30 oz-in (2.2 kg-cm) and 1.6 A at stall.

These tiny brushed DC gearmotors are available in a wide range of gear ratios—from 5:1 up to 1000:1—and with five different motors: high-power 6 V and 12 V motors with long-life carbon brushes (HPCB), and high-power (HP), medium power (MP), and low power (LP) 6 V motors with shorter-life precious metal brushes. The 6 V and 12 V HPCB motors offer the same performance at their respective nominal voltages, just with the 12 V motor drawing half the current of the 6 V motor. The 6 V HPCB and 6 V HP motors are identical except for their brushes, which only affect the lifetime of the motor.

The HPCB versions (shown on the left in the picture below) can be differentiated from versions with precious metal brushes (shown on the right) by their copper-colored terminals. Note that the HPCB terminals are 0.5 mm wider than those on the other micro metal gearmotor versions (2 mm vs. 1.5 mm), and they are about 1 mm closer together (6 mm vs. 7 mm).

Versions of these gearmotors are also available with an additional 1 mm-diameter output shaft that protrudes from the rear of the motor. This 4.5 mm-long rear shaft rotates at the same speed as the input to the gearbox and offers a way to add an encoder, such as our magnetic encoder for micro metal gearmotors (see the picture on the right), to provide motor speed or position feedback.

With the exception of the 1000:1 gear ratio versions, all of the micro metal gearmotors have the same physical dimensions, so one version can be easily swapped for another if your design requirements change.

Please see the micro metal gearmotor datasheet (2MB pdf) for more information, including detailed performance graphs for each micro metal gearmotor version. You can also use our dynamically sortable micro metal gearmotor comparison table for search for the gearmotor that offers the best blend of speed, torque, and current-draw for your particular application. A more basic comparison table is available below.

Note: Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. The recommended upper limit for instantaneous torque is 35 oz-in (2.5 kg-cm) for the 1000:1 gearboxes and 25 oz-in (2 kg*cm) for all the other gear ratios; we strongly advise keeping applied loads well under this limit. Stalls can also result in rapid (potentially on the order of seconds) thermal damage to the motor windings and brushes, especially for the versions that use high-power (HP and HPCB) motors; 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; lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor.

Exact gear ratio: ``(35×37×35×38) / (12×11×13×10) ~~ bb(100.37:1)``

In terms of size, these gearmotors are very similar to Sanyo’s popular 12 mm NA4S DC gearmotors, and gearmotors with this form factor are occasionally referred to as N20 motors. The versions with carbon brushes (HPCB) have slightly different terminal and end-cap dimensions than the versions with precious metal brushes, but all of the other dimensions are identical.

Dimensions of versions with carbon brushes (HPCB)

Dimensions of the Pololu micro metal gearmotors with carbon brushes (HPCB). Units are mm over [inches].

Dimensions of versions with precious metal brushes (LP, MP, and HP)

Dimensions of the Pololu micro metal gearmotors with precious metal brushes: low-power (LP), medium-power (MP), and high-power (HP). Units are mm over [inches].

These diagrams are also available as a downloadable PDF (262k pdf).

Wheels and hubs: The micro metal gearmotor’s output shaft matches our assortment of Pololu wheels and the Solarbotics RW2i rubber wheel. You can also use our Pololu universal mounting hubs to mount custom wheels and mechanism to the micro metal gearmotor’s output shaft, and you can use our 12mm hex wheel adapter to use this motor with many common hobby RC wheels.

Pololu wheel 32×7mm on a micro metal gearmotor.

Black Pololu 70×8mm wheel on a Pololu micro metal gearmotor.

A pair of Pololu universal aluminum mounting hubs for 3 mm diameter shafts.

12mm Hex Wheel Adapter for 3mm Shaft on a Micro Metal Gearmotor.

Mounting brackets: Our mounting bracket (also available in white) and extended mounting bracket are specifically designed to securely mount the gearmotor while enclosing the exposed gears. We recommend the extended mounting bracket for wheels with recessed hubs, such as the Pololu wheel 42×19mm. Our micro metal gearmotors will also work with our 15.5D mm metal gearmotor bracket pair.

Black micro metal gearmotor mounting bracket pair with included screws and nuts.

White micro metal gearmotor mounting bracket pair with included screws and nuts.

Pololu micro metal gearmotor bracket extended with micro metal gearmotor.

Quadrature encoders: We offer several quadrature encoders that work with our micro metal gearmotors.

Magnetic Encoder Kit for Micro Metal Gearmotors assembled with ribbon cable wires.

Example of an installed micro metal gearmotor reflective optical encoder.

Note: The HPCB versions of our micro metal gearmotors are not compatible with our #2590 and #2591 optical encoders or our older #2598 magnetic encoders (the terminals are too wide to fit through the corresponding holes in the encoder boards). However, they are compatible with our newer #3081 magnetic encoders.

Motor controllers and drivers: We have a number of motor controllers, motor drivers, and robot controllers that make it easy to drive these micro metal gearmotors. For the 6 V micro metal gearmotors, consider the DRV8838 single-channel motor driver carrier, the DRV8833 dual motor driver carrier, and DRV8835 dual motor driver carrier (or DRV8835 shield for Arduino). For the 12 V micro metal gearmotors, consider the MAX14870 single-channel motor driver carrier, DRV8801 single-channel motor driver carrier, and A4990 dual motor driver carrier (or A4990 shield for Arduino).

DRV8838 Single Brushed DC Motor Driver Carrier.

Pololu A4990 Dual Motor Driver Shield for Arduino, bottom view.

DRV8835 dual motor driver carrier.

Current sensors: We have an assortment of Hall effect-based current sensors to choose from for those who need to monitor motor current:

ACS711EX current sensor carrier -15.5A to +15.5A.

ACS714 current sensor carrier -5A to +5A.

We also incorporate these motors into some of our products, including our Zumo robot and 3pi robot :

Assembled Zumo 32U4 robot.

Pololu 3pi robot.

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.

People often buy this product together with:

These standard gearmotors are incredibly tough and feature full metal gears to help you drive wheels, gears, or almost anything else that needs to turn. They have a gear ratio of 18:1 and operate up to 12 volts and deliver a stall torque of 27.3 oz-in. and a max speed of 168 RPM. Each standard gearmotor sports a 6mm diameter D-shaft.

Features

Voltage: 3 - 12 Volts

Gear Ratio: 18:1

Stall Torque: 27.3 oz-in. (@ 12V)

Speed: 168 RPM (@ 12V)

No Load Current: 95 mA (@ 12V)

Stall Current: 0.5A (@ 12V)

Insulation Resistance: 10 MOhm

Dielectric Strength: 300VDC

DC Reversible

Shaft Size: 6mm Diameter x 0.715” Length

Weight: 4.2 oz.

Add quadrature encoders to your LP, MP, or HP micro metal gearmotors (extended back shaft version required) with this kit that uses a magnetic disc and hall effect sensors to provide 12 counts per revolution of the motor shaft. The sensors operate from 2.7 V to 18 V and provide digital outputs that can be connected directly to a microcontroller or other digital circuit.Note: This version is not compatible with the HPCB micro metal gearmotors; it is only compatible with LP, MP, and HP dual-shaft micro metal gearmotors.

Discontinuation notice: This encoder is not compatible with our HPCB micro metal gearmotors (the HPCB motor terminals are too large to fit the corresponding PCB holes), but it is compatible with the LP, MP, and HP versions of our micro metal gearmotors. We have released a new version of this board that enlarges the motor terminal holes so they are compatible with all our micro metal gearmotors. The new version is functionally identical to this older version and can serve as a drop-in replacement. We will be discontinuing this product when the remaining stock is gone.

These older encoders are now only available by large-volume special order. Please contact us for more information.

Magnetic Encoder Kit for Micro Metal Gearmotors (old version; not compatible with HPCB micro metal gearmotors).

Magnetic Encoder Kit for Micro Metal Gearmotors (HPCB compatible).

This kit includes two dual-channel Hall Effect sensor boards and two 6-pole magnetic discs that can be used to add quadrature encoding to two micro metal gearmotors with extended back shafts (motors are not included with this kit). The encoder board senses the rotation of the magnetic disc and provides a resolution of 12 counts per revolution of the motor shaft when counting both edges of both channels. To compute the counts per revolution of the gearbox output shaft, multiply the gear ratio by 12.

This compact encoder solution fits within the 12 mm × 10 mm cross section of the motors on three of the four sides, and it only extends 0.6 mm past the edge of the fourth side (note: if you need it to be flush with that last side, you can carefully grind the board down a little and solder to the remaining half-holes). The assembly does not extend past the end of the extended motor shaft, which protrudes 5 mm beyond the plastic end cap on the back of the motor.

Note: This sensor system is intended for users comfortable with the physical encoder installation. It only works with micro metal gearmotors that have extended back shafts.

The encoder board is designed to be soldered directly to the back of the motor, with the back shaft of the motor protruding through the hole in the middle of the circuit board. One way to achieve good alignment between the board and the motor is to tack down the board to one motor pin and to solder the other pin only when the board is flat and well aligned. Be careful to avoid prolonged heating of the motor pins, which could deform the plastic end cap of the motor or the motor brushes. Once the board is soldered down to the two terminals, the motor leads are connected to the M1 and M2 pads along the edge of the board; the remaining four pads are used to power the sensors and access the two quadrature outputs:

The sensors are powered through the VCC and GND pins. VCC can be 2.7 V to 18 V, and the quadrature outputs A and B are digital signals that are either driven low (0 V) by the sensors or pulled to VCC through 10 kΩ pull-up resistors, depending on the applied magnetic field. The sensors’ comparators have built-in hysteresis, which prevents spurious signals in cases where the motor stops near a transition point.

Encoder A and B outputs of a magnetic encoder on a high-power (HP) micro metal gearmotor running at 6 V.

The board’s six pads have a 2 mm pitch, so they do not work with common 0.1″ connectors. One option for connecting to the board is to solder in individual wires, such as in the example below:

Alternatively, you can solder a 2mm-pitch connector to the board. The examples below show a male header, which gives you the option of making a detachable cable terminated by a 6-pin 2mm-pitch female header. If the pins are angled over the motor, as shown in the picture below, they will just barely protrude through the holes in the board. Note that in this orientation, there is room to plug in a female header even when our extended micro metal gearmotor bracket is being used.

If the pins are pointed away from the motor, they will need to be angled so that they sufficiently clear the magnetic disc. With a decent soldering iron, it is possible to solder them in this orientation even after the encoder has been installed on the motor.

Once the board is soldered to the motor, the magnetic encoder disc can be pushed onto the motor shaft. One easy way to accomplish this is to press the motor onto the disc while it is sitting on a flat surface, pushing until the shaft makes contact with that surface. The size of the gap between the encoder disc and the sensor board does not have a big impact on performance as long as the motor shaft is at least all the way through the disc.

This schematic is also available as a downloadable pdf (125k pdf).

People often buy this product together with:

This gearmotor is a miniature high-power, 6 V brushed DC motor with long-life carbon brushes and a 248.98:1 metal gearbox. It has a cross section of 10 × 12 mm, and the D-shaped gearbox output shaft is 9 mm long and 3 mm in diameter.

Key specifications:

voltage

no-load performance

stall extrapolation

6 V

130 RPM, 100 mA

3.2 kg⋅cm (44 oz⋅in), 1.5 A

These tiny brushed DC gearmotors are available in a wide range of gear ratios—from 5:1 up to 1000:1—and with five different motors: high-power 6 V and 12 V motors with long-life carbon brushes (HPCB), and high-power (HP), medium power (MP), and low power (LP) 6 V motors with shorter-life precious metal brushes. The 6 V and 12 V HPCB motors offer the same performance at their respective nominal voltages, just with the 12 V motor drawing half the current of the 6 V motor. The 6 V HPCB and 6 V HP motors are identical except for their brushes, which only affect the lifetime of the motor.

The HPCB versions (shown on the left in the picture below) can be differentiated from versions with precious metal brushes (shown on the right) by their copper-colored terminals. Note that the HPCB terminals are 0.5 mm wider than those on the other micro metal gearmotor versions (2 mm vs. 1.5 mm), and they are about 1 mm closer together (6 mm vs. 7 mm).

Versions of these gearmotors are also available with an additional 1 mm-diameter output shaft that protrudes from the rear of the motor. This 4.5 mm-long rear shaft rotates at the same speed as the input to the gearbox and offers a way to add an encoder, such as our magnetic encoder for micro metal gearmotors (see the picture on the right), to provide motor speed or position feedback.

With the exception of the 1000:1 gear ratio versions, all of the micro metal gearmotors have the same physical dimensions, so one version can be easily swapped for another if your design requirements change.

Please see the micro metal gearmotor datasheet (2MB pdf) for more information, including detailed performance graphs for each micro metal gearmotor version. You can also use our dynamically sortable micro metal gearmotor comparison table for search for the gearmotor that offers the best blend of speed, torque, and current-draw for your particular application. A more basic comparison table is available below.

Note: Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. The recommended upper limit for instantaneous torque is 35 oz-in (2.5 kg-cm) for the 1000:1 gearboxes and 25 oz-in (2 kg*cm) for all the other gear ratios; we strongly advise keeping applied loads well under this limit. Stalls can also result in rapid (potentially on the order of seconds) thermal damage to the motor windings and brushes, especially for the versions that use high-power (HP and HPCB) motors; 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; lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor.

Exact gear ratio: ``(25×34×37×35×38) / (12×10×10×14×10) ~~ bb(248.98:1)``

In terms of size, these gearmotors are very similar to Sanyo’s popular 12 mm NA4S DC gearmotors, and gearmotors with this form factor are occasionally referred to as N20 motors. The versions with carbon brushes (HPCB) have slightly different terminal and end-cap dimensions than the versions with precious metal brushes, but all of the other dimensions are identical.

Dimensions of versions with carbon brushes (HPCB)

Dimensions of the Pololu micro metal gearmotors with carbon brushes (HPCB). Units are mm over [inches].

Dimensions of versions with precious metal brushes (LP, MP, and HP)

Dimensions of the Pololu micro metal gearmotors with precious metal brushes: low-power (LP), medium-power (MP), and high-power (HP). Units are mm over [inches].

These diagrams are also available as a downloadable PDF (262k pdf).

Wheels and hubs: The micro metal gearmotor’s output shaft matches our assortment of Pololu wheels and the Solarbotics RW2i rubber wheel. You can also use our Pololu universal mounting hubs to mount custom wheels and mechanism to the micro metal gearmotor’s output shaft, and you can use our 12mm hex wheel adapter to use this motor with many common hobby RC wheels.

Pololu wheel 32×7mm on a micro metal gearmotor.

Black Pololu 70×8mm wheel on a Pololu micro metal gearmotor.

A pair of Pololu universal aluminum mounting hubs for 3 mm diameter shafts.

12mm Hex Wheel Adapter for 3mm Shaft on a Micro Metal Gearmotor.

Mounting brackets: Our mounting bracket (also available in white) and extended mounting bracket are specifically designed to securely mount the gearmotor while enclosing the exposed gears. We recommend the extended mounting bracket for wheels with recessed hubs, such as the Pololu wheel 42×19mm. Our micro metal gearmotors will also work with our 15.5D mm metal gearmotor bracket pair.

Black micro metal gearmotor mounting bracket pair with included screws and nuts.

White micro metal gearmotor mounting bracket pair with included screws and nuts.

Pololu micro metal gearmotor bracket extended with micro metal gearmotor.

Quadrature encoders: We offer several quadrature encoders that work with our micro metal gearmotors.

Magnetic Encoder on a Micro Metal Gearmotor with Extended Motor Shaft, assembled with ribbon cable wires.

Example of an installed micro metal gearmotor reflective optical encoder.

Note: The HPCB versions of our micro metal gearmotors are not compatible with our #2590 and #2591 optical encoders or our older #2598 magnetic encoders (the terminals are too wide to fit through the corresponding holes in the encoder boards). However, they are compatible with our newer #3081 magnetic encoders.

Motor controllers and drivers: We have a number of motor controllers, motor drivers, and robot controllers that make it easy to drive these micro metal gearmotors. For the 6 V micro metal gearmotors, consider the DRV8838 single-channel motor driver carrier, the DRV8833 dual motor driver carrier, and DRV8835 dual motor driver carrier (or DRV8835 shield for Arduino). For the 12 V micro metal gearmotors, consider the MAX14870 single-channel motor driver carrier, DRV8801 single-channel motor driver carrier, and A4990 dual motor driver carrier (or A4990 shield for Arduino).

DRV8838 Single Brushed DC Motor Driver Carrier.

Pololu A4990 Dual Motor Driver Shield for Arduino, bottom view.

DRV8835 dual motor driver carrier.

Current sensors: We have an assortment of Hall effect-based current sensors to choose from for those who need to monitor motor current:

ACS711EX current sensor carrier -15.5A to +15.5A.

ACS714 current sensor carrier -5A to +5A.

We also incorporate these motors into some of our products, including our Zumo robot and 3pi robot :

Assembled Zumo 32U4 robot.

Pololu 3pi robot.

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.

People often buy this product together with: