ORCAD - Oscillator startup
In real life, transients and/or noise start oscillations in oscillators. In a simulation, everything is ideal and no noise is around. Furthermore, connecting dc Voltage source to your circuit and simulating, it most likely just goes to steady state and has no transient. Unfortunately that transient is what would kick start the oscillator if and only if the oscillator is properly designed and configured correct with proper values for gain. Too many times to say proper? 

Fortunately there’s a way: replace your dc voltages with step voltage sources. They would be the same voltage value but have a step look to it with a rise time of 10ns should do it. Then view the output in transient mode. This usually works.