298:1 Micro Metal Gearmotor HP with Extended Motor Shaft - pololu - #2218

Overview

These tiny brushed DC gearmotors are intended for use at 6 V, though 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 (rotation can start at voltages as low as 0.5 V). Lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor. The micro metal gearmotors are available in a wide range of gear ratios—from 5:1 up to 1000:1—and with four different motors: high-power with long-life carbon brushes (HPCB), high-power with shorter-life precious metal brushes (HP), medium-power (MP), and low-power. The HPCB version (shown on the left in the picture below) can be differentiated from versions with precious metal brushes (shown on the right) by its 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).

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  for detailed specifications of all our micro 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.

Some versions of the gearmotors are 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  (see the picture on the right), to provide motor speed or position feedback.

Motor Type	Stall Current @ 6 V	No-Load Speed @ 6 V	Approximate Stall Torque @ 6 V	Single-Shaft (Gearbox Only)	Dual-Shaft (Gearbox & Motor)
high-power, carbon brushes (HPCB)	1600 mA	3000 RPM	4 oz-in
		1000 RPM	9 oz-in
		625 RPM	15 oz-in
		400 RPM	22 oz-in
		320 RPM	30 oz-in
		200 RPM	40 oz-in
		140 RPM	50 oz-in
		120 RPM	60 oz-in
		100 RPM	70 oz-in
		32 RPM	125 oz-in
high-power (HP) (same specs as HPCB above)	1600 mA	6000 RPM	2 oz-in
		3000 RPM	4 oz-in
		1000 RPM	9 oz-in
		625 RPM	15 oz-in
		400 RPM	22 oz-in
		320 RPM	30 oz-in
		200 RPM	40 oz-in
		140 RPM	50 oz-in
		120 RPM	60 oz-in
		100 RPM	70 oz-in
		32 RPM	125 oz-in
medium-power (MP)	700 mA	2200 RPM	3 oz-in
		730 RPM	8 oz-in
		420 RPM	13 oz-in
		290 RPM	17 oz-in
		220 RPM	19 oz-in
		150 RPM	24 oz-in
		75 RPM	46 oz-in
		25 RPM	80 oz-in
low-power	360 mA	2500 RPM	1 oz-in
		1300 RPM	2 oz-in
		440 RPM	4 oz-in
		250 RPM	7 oz-in
		170 RPM	9 oz-in
		120 RPM	12 oz-in
		85 RPM	17 oz-in
		60 RPM	27 oz-in
		50 RPM	32 oz-in
		45 RPM	40 oz-in
		14 RPM	70 oz-in

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.

Details for item #2218

Exact gear ratio:  25×34×37×35×3812×9×10×13×10≈297.92:1

Gearmotor Dimensions

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 (low-power, MP, and HP)

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

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

Motor Accessories

• Wheels and hubs: The micro metal gearmotor’s output shaft matches our assortment of  and the . You can also use our  to mount custom wheels and mechanism to the micro metal gearmotor’s output shaft, and you can use our  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  (also available in ) and  are specifically designed to securely mount the gearmotor while enclosing the exposed gears. We recommend the