[en] Results are presented from a new variational calculation of quantized SU(3) Yang-Mills fields. The Hamiltonian formalism is applied to the continuum theory, with a truncated momentum expansion in a finite volume, using the Coulomb gauge. The relative importance of electrical and magnetic effects is examined, using an improved treatment of paramagnetic effects. The results depend on the value of the interaction constant, with a transition at α /approximately/ 0.4. For α > 0, there is a mass gap between the first excited state and the vacuum state, arising from properties of the Faddeev-Popov determinant. For a /approx gt/ 0.4, properties of the Coulomb energy operator lead to a second mass gap between the first and the higher excited states. 33 refs., 3 figs