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78:1 Metal Gearmotor 20Dx43L mm 6V CB

Pololu item #: 3703
Brand: Pololu supply outlook
Status: Active and Preferred 
RoHS 3 compliant


Price break Unit price (US$)
1 28.95
5 26.63
25 24.50
100 22.54


backorders allowed

These small brushed DC gearmotors can deliver a lot of power for their size. This version has a 6V brushed DC motor with long-life carbon brushes combined with a 78.13:1 metal spur gearbox. The gearmotor is cylindrical with a diameter of 20 mm, and the D-shaped output shaft is 4 mm in diameter and extends 18 mm from the face plate of the gearbox.

Key specifications:

voltage no-load performance stall extrapolation
6 V 180 RPM, 150 mA 4.4 kg⋅cm (61 oz⋅in), 2.9 A

Alternatives available with variations in these parameter(s): gear ratio motor type extended motor shaft? Select variant…

 Description Specs (17) Pictures (14) Resources (3) FAQs (3) On the blog (0) 
Is it okay to stall this motor at its operating voltage?

No! Stalls can 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, which means keeping continuously applied loads around 25% or less of the stall torque.

Additionally, for many of our gearmotors with high gear ratios, the extrapolated stall torque is beyond what the gearboxes are designed to handle, and a stall could instantly damage the gears. Make sure to keep applied loads within the published limits for your gearmotor.

What do the dotted lines mean in the motor performance curves from the datasheet?
In our motor performance curves, the solid lines show the regions where we actually took measurements while the dotted lines show extrapolations beyond that. For many motors, we took measurements out to about 50% of the stall torque, since continued operation at loads past this point increasingly risk thermal damage to the windings. However, for higher gear ratios, going to 50% of the stall torque exceeds what is safe for the gearbox, so the measurements are further limited to not much past our recommendation for continuously applied loads.
What material is the gearbox output shaft made of, and can I get the shaft customized?
The shaft is composed of hardened stainless steel. Some customization is generally possible (e.g., different length or no D-shaft) for sufficiently high-volume orders. If this is something you are interested in, please email us.

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Related Categories

6V Carbon Brush (CB) 20D Gearmotors
4mm Shaft Gearmotors
Pololu Metal Gearmotors
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Brushed DC Motor Controllers
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