Since single-sided linear induction motors working with a lateral asymmetric cap secondary is a frequent operating condition, this paper develops an equivalent circuit model considering the asymmetric condition. First, an analysis model, which takes the longitudinal end effect and skin effect into consideration, is proposed. Second, a transversal analysis model considering the laterally asymmetric cap secondary is developed to derive its correction factors. Then, the influence of lamination eddy current on the effective air gap to transversely directed flux is contrastively analyzed. Third, the traction characteristics of a prototype motor with symmetric and asymmetric cap secondary are calculated by the equivalent circuit. Finally, these calculated results are verified by measurements carried out by a test rig of the linear motor.