Abstract We consider the oscillations of a rotating pendulum or its analogy of a bead on a rotating, vertical, circular wire as a model example of a non-linear system with a periodic restoring force. Exact solutions are known for the homoclinic and heteroclinic orbits of the autonomous, unperturbed conservative system in terms of a parameter proportional to the angular velocity of the wire. When this system is perturbed by dissipative and excitation terms, which do not depend explicitly on time, we use planar Melnikov techniques to determine a parameter set which preserves the co-existence of both heteroclinicandhomoclinic orbits. If an external sinusoidal torque is applied axially along the wire, the orbits may develop into heterclinic and homoclinic tangles caused by the consequent horseshoe manifold intersections. In particular, within this system two distinct types of horseshoe are shown to exist. Moreover, we determine some special parameter relationships which predict when both types of horseshoe co-exist but do not interact despite very large forcing amplitudes. Finally, we show numerical results based on this observation, and describe Poincar e maps in a critical section in the parameter space.