The planetary transmission efficiency is determined the reduction ratio of gear stage output. The stage of planetary reducer is composed of the sun wheel and its surrounding planet wheel. If there is only one gear system in the reducer, we call it "a section (stage)" in order to get a larger reduction ratio, multiple sections (stages) transmission is needed. Because one set of planetary gears cannot meet a larger transmission ratio, sometimes two or three sets are required to meet the user's requirements for a larger transmission ratio. Due to the increase in the number of planetary gears, the length of the second or third engine reduction stage will be increased and the efficiency will be reduced. Planetary reducer series is not the same, transmission efficiency is not the same, usually not more than three, the smaller the series transmission efficiency is higher, the smaller the opposite.  

One stage (single stage) transmission efficiency is 98%.

Secondary transmission efficiency 98%×98%.

Three-stage transmission efficiency is 98%×98%×98%.Planetary reducer full load efficiency: Transmission efficiency of planetary reducer under heavy load conditions (failure stop output torque).

Calculation formula of planetary gear reducer efficiency: 

Planetary gear box: first stage: η=0.90.999% (normal ST28P/ST32P/ST36P/ST42P are calculated as follows)

56% (ST16P/ST22P low efficiency based on this calculation, the technical department needs to improve)

Multistage: η=η1*0.9