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Showing results for tags 'automatic gearbox'.
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TechnicBrickPower posted a topic in LEGO Technic and Model TeamHi All, Here's a video I did on optimal gear switching ratios for PF motors. A formula presented relating the power operating point as a percentage of peak power. From this an operational power range band is defined based on maintaining a power efficiency of at least E percent. From this, optimal switching points relative to the motor torque are derived and the correct gear switching ratio determined. These are presented as formulas and graphs. The peak torque and power points are shown for Lego technic PF medium motors, Lego Techinc PF Large Motors and Lego Technic PF XL Motors.
TechnicBrickPower posted a topic in LEGO Technic and Model TeamHi all, the instructions for an MOC automatic gearbox that I made a while ago are now available on Rebrickable. https://rebrickable.com/mocs/MOC-48521/TechnicBrickPower/3-speed-automatic-gearbox youtube video on how it works: :
Here's my 3 speed automatic gearbox MOC. The gearbox automatically switches between one of 3 gear ratios, namely a ratio of 1, 1/3rd and 1/9th depending on the load on the output. It uses two 2 speed automatic transmissions in series to create the three speed automatic gearbox. It works on the principle of 2 degrees of freedom within a pair of differentials. This creates two gear paths for the transmission of force and the path of least resistance is taken. The loading points at which this lego gearbox switches gears is adjustable via two linear actuators at the bottom of the gearbox, which adjust the amount of artificially introduced friction to control the switch over points. Hope you like it.