These gearbox motors (also known as'TT' motors) are an easy, low-cost way to get your projects moving.

This is a TT DC All-MetalGearbox Motor with a gear-ratio of 1:90 aboutdouble ofthe 'standard' 1:48 ratio.

That gives them higher torque butslower rotational speed.

Since they're slower they're good for robotswhere strength is more important than speed.

They look a lot like our yellow all-plastic-gearbox motors but these have all of the motorgears machined from steel, so they won't strip as easily, and they're twice asslow (and twice as powerful) given their lower gearbox ratio. The metal gearsalso mean they're louder when running.

You can power these motors with 3VDC upto 6VDC, they'll of course go a little faster at the higher voltages. Wegrabbed one motor and found these stats when running it from a bench-top supply

·        At 3VDC wemeasured 80mA @ 60 RPM no-load, and 0.5 Amps when stalled

·        At 4.5VDC wemeasured 90mA @ 90 RPM no-load, and 0.8 Amps when stalled

·        At 6VDC wemeasured 100mA @ 120 RPM no-load, and 1.0 Amps when stalled

Note that these are very basic motors,and have no built-in encoders, speed control or positional feedback. Voltagegoes in, rotation goes out! There will be variation from motor to motor, so aseparate feedback system is required if you need precision movement.