  This article studies the rotational dynamics of three identical coupled
pendulums. There exist two parameter areas where the in-phase rotational motion
is unstable and out-of-phase rotations are realized. Asymptotic theory is
developed that allows to analytically identify boarders of instability areas of
in-phase rotation motion. It is shown that out-of-phase rotations are the
result of parametric instability of in-phase motion. Complex out-of-phase
rotations are numerically found and their stability and bifurcations are
defined. It is demonstrated that emergence of chaotic dynamics happens due
period doubling bifurcation cascade. The detail scenario of symmetry breaking
is presented. The development of chaotic dynamics leads to origin of two
chaotic attractors of different types. The first one is characterized by the
different phases of all pendulums. In the second case the phases of two
pendulums are equal, and the phase of the third one is different. This regime
with partial symmetry breaking is a chaotic chimera.
