I am trying to run a simulation of a planetary gear system consist of four planetary gears, one sun gear & a ring gear. The planet gears will be revolving around the sun & the ring gear. I am trying to run this simulation on Promotion but I am having problems. I already defined the gear connections, material & has made the sun gear as a driver & give it a certain angular velocity. Every time when I try to run the moton analysis on it, I got the message showing that engine is not connected. Can anybody help me in this problem?