1,small size 2,cheap/low cost 3,widely used 4,ISO9001 and CE 5,can be customized and OEM power transformer; voltage transformer ... -SEC,PRI-CORE:AC2KV 50Hz 1MA FOR 60S:SEC-CORE:AC3KV 50HZ 0.58MA FOR 10S4.5Insulation ResistancePRI-SEC,PRI-CORE,SEC-CORE 100MΩ min ... voltage testAll secondary windings open input Primary 300V 400Hz for 15 secongds hall withstand without breakdown5.0humidityAfter 48 hours ...