If I input the joints as you have suggested, then where should i put the joint loads. I have two joint loads. One is the sun revolute joint which has moment and the other is the planet revolute joint which has rotation from 0 to 60 degrees as its load. What I want is that the with a particular torque of sun gear, I want the planet to revolve from 0 to 60 degrees. With this simulation,  I want to see the stresses developed in the planet gear and the Ring gear. And should I or should I not use a PLANAR JOINT ? Also is there a need to use constraint Equation ?