The use of high-Tc superconducting synchronous motor in power machinery has many advantages such as reduced power dissipation, size and weight. This paper presents the ac loss simulation in the rotor having an high-Tc superconducting field winding using Ag sheathed Bi-2223. The analysis was conducted with an equivalent model of the high-Tc superconducting motor with flux damper under transition condition during which the load varies from 0 watt to 250watts and from 250watts to 500watts. The simulation results show that the transient state lasts for about 3 seconds, and the ac losses decreased exponentially from the initial value above 20mW.