Little Bird · Component atlas

Inside a TT geared DC motor

Follow electrical energy through a brushed motor and reduction gears.

Loading the 3D motor…

Drag to orbit · scroll or pinch to zoom

48Motor turns / wheel turn

100%Relative output speed*

1.0×Ideal torque multiplier*

Open the case 0%IntactInsideTurn the output shaft 0.00 turnStartOne revolution

Battery connected · electrical energy turns the motor and gears

Choose the gearbox

Gear reduction

*With the same motor speed and before gearbox losses. These ratios compare the mechanisms; they do not predict the speed or torque of a particular student build.

What changes when you swap the leads?

The battery reverses current through the brushed motor. Its rotor and every gear reverse, so both ends of the output shaft reverse together.

What does the gearbox do?

Small driver gears turn larger gears. The model uses visible tooth counts whose stage ratios multiply to 48:1 or 120:1. More reduction trades output speed for mechanical advantage.

Follow currentConventional current + → −

In the vehicle

Drag to orbit. Open the case to follow the brushed motor, compound gears and two ends of the output shaft.

Two AA cells provide about 3 V nominal.
Use the 120:1 bare-lead motor for a light chassis and clip-on power.
Keep the front skewer in straw bearings so it turns freely.

Build a classroom vehicle

One motor, a switched 2×AA holder, TT-compatible wheels and a cardboard chassis. Test polarity, wheel drag and energy transfer.

Open the project ↗