Description

Overview

These cylindrical brushed DC gearmotors are available in a wide range of gear ratios, from 25:1 up to 488:1, and with three different motors: 6 V and 12 V motors with long-life carbon brushes (CB), and a 6 V motor with shorter-life precious metal brushes. All three motors offer similar performances at their respective nominal voltages, just with the 12 V motor drawing approximately half the current of the 6 V motor and with the carbon brush versions having longer lifetimes than the one with precious metal brushes.

The CB versions (shown on the right in the picture below), can be differentiated from versions with percious metal brushes (shown on the left) by their copper-colored terminals.

The gearmotors all have 20 mm diameter gearboxes and 4 mm diameter gearbox output shafts, 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).

Please see the 20D metal gearmotor datasheet (1MB pdf) for more information, including detailed performance graphs for each 6V CB and 12V CB version. You can also use our dynamically sortable 20D metal gearmotor comparison table to search for the version that offers the best combination of speed, torque, and current draw for your particular application.

Note: Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. In order to avoid damaging the gearbox, we recommend keeping continuously applied loads under 5 kg-cm (75 oz-in) for the versions with carbon brushes (12V CB and 6V CB) and under 3.5 kg-cm (50 oz-in) for the versions with precious metal brushes. Stalls can also result in rapid (potentially on the order of seconds) thermal damage to the motor windings and brushes, especially for motors like this that can deliver a lot of power for their size; a general recommendation for brushed DC motors is to limit continuous current to approximately 25% 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.

Details for item #3463

Exact gear ratio: 28×25×25×25/14×10×10×10=31.25:1

Dimensions

Warning: Do not screw too far into the mounting holes as the screws can hit the gears. We recommend screwing no more than 3.5 mm (0.14″) into the M2.5 mounting holes.

Gearmotor accessories

The gearmotor face plate has two mounting holes threaded for M2.5 screws, and you can use our custom-designed 20D mm metal gearmotor bracket (shown in the left picture below) to mount the gearmotor to your project via these mounting holes and the screws that come with the bracket.

We have a number of motor controllers and motor drivers that work with these 20D mm metal gearmotors. In particular, we recommend our MC33296-based motor drivers, for which we have basic single and dual carriers and a dual-channel shield for Arduino. Our VNH5019-based motor drivers (available as single and dual carriers) also work well with these motors, and because they can handle higher currents, 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 serial, consider our SMC 18v7, Jrk 21v3, or TReX Jr.

Pololu dual MC33926 motor driver shield for Arduino.

VNH5019 motor driver carrier.

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.

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.

Specs

Dimensions

Size:	20D × 41L mm
Weight:	43 g
Shaft diameter:	4 mm

General specifications

Gear ratio:	31.25:1
No-load speed @ 6V:	470 rpm
No-load current @ 6V:	170 mA
Stall current @ 6V:	2.9 A1
Stall torque @ 6V:	28 oz·in1
Extended motor shaft?:	Y
Motor type:	2.9A stall @ 6V

Notes:

1

Stalling is likely to damage the gearmotor. 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.