The present paper derives a new general zero-sequence steady state ladder equivalent circuit of threephase induction machines where zero-sequence currents can simultaneously flow in both the stator and rotor windings. A general expression for the zero-sequence torque is also derived. In machines with even number of phases, anti-zero sequence currents can also flow. It is shown that they can produce a finite torque and a new anti-zero-sequence steady state equivalent circuit of induction machines is presented. This is shown to be similar to the space-harmonic equivalent circuit of a single-phase induction machine, where the number of polepairs is equal to one half of the stator phase number.