These sound nearly identical to some of the C151 MRT trains here in Singapore, a few of which were refitted with the same Toshiba PMSM motors as the JR Kyushu 305 Series trains. They were originally intended to be fitted on all C151-type trains here as part of a refurbishment program, and initially two trains were refitted to test the motors in real-world running scenarios. After the refurbishment program was cancelled (as they decided to purchase new trains instead), the company decided to refit a few additional trains with the PMSM motors anyway as the old Mitsubishi GTO Chopper motors (which are in turn similar to those fitted on some of Tokyo Metro's 03 Series and 05 Series trains) were becoming too worn-out, apparently; the new trains that would eventually replace them would still need to take a few years to arrive, and they will still be needed in service until then.