اتوترانس 3 فاز  ، واریابل  3 فاز 

EXTECH/USA FLIR/USA UNI-T/CHINA AZ/TAIWAN LUTRON/TAIWAN KYORITSU/JAPAN HIOKI/JAPAN TESTO/GERMANY FLUKE/USA HONEYWELL/CANADA ADDITEL/USA B.T.M LEICA/HUNGARY,AUSTRIA CEM/CHINA MASTECH/CHINA KIMO/FRANCE MET ONE/USA INSIZE/CHINA ROSEMOUNT/USA MEGGER/ENG MARMONIX/CANADA SEBAKMT/GERMANY GW INSTEK/TAIWAN HANNA/USA BENETECH/CHINA WIKA/GERMANY FLUKE NETWORKS/USA SCHNEIDER/FRANCE hanyoung/korea Mitutoyo HANTEK VICTOR YDS/China Rigol/china PCE/Germany Pintech/china SIEMENS/GERMANY YOKOGAWA omron/Japan Deep Sea smart sensor IET-Labs POLIMASTER SEW