In this study, it is demonstrated that the iron loss from the SiC-MOSFET, which is a new power semiconductor with an extremely low on-voltage for electric machine drives is almost the same as that from Si-IGBT, which is a conventional power semiconductor. In order to evaluate the iron loss characteristics when a SiC device is used, two single-phase PWM inverters are built and used for the excitation of a ring made of electrical steel sheets. One of the inverter employs a SiC-MOSFET, and the other inverter employs a Si-IGBT. Then, the iron losses for the two inverters are compared.