Some soft starters have back-to-back SCRs in all three phases legs (i.e., 6 SCRs total). Others have back-to-back SCRs in only two phase legs (i.e., 4 SCRs total). Motor has delta-connected windings. Do the soft starters having SCRs in only two legs create unbalanced currents or voltages...
Installation is a 50 Hp 3-phase motor driving a pump. Power source is 480V V-phase from two single phase transformers connected in an open-wye primary and open-delta secondary. Motor is delta connected. V-phase driving 3-phase motors is not uncommon in rural U.S. areas (i.e. farms) where true...