The highest quality motor with a high efficiency planetary gear as the main drive of a mobile robot. The economical series of DC commutator motors with planetary gearbox 1.61.077.4xx from Buehler Motor GmbH is available from WObit. A series of 31mm diameter motors with a 7-segment commutator is equipped with planetary gears in a plastic housing with the same diameter and a ratio of 12 to 250: 1. Thanks to the use of a planetary gear, the power unit has a high efficiency. The 1.61.077.414 engine with a transmission shown in the picture has a rated speed of 40 rpm and reaches a rated torque of 1Nm with 12V rated current of 860mA. The engine operating temperature range is from -20 ° C to + 70 ° C. The motor has a lead-out shaft, for example for mounting the encoder. Soon the engine version with an integrated incremental encoder will be available.