User Manual EM303B General Purpose Inverter 3.2.3 Internal Main Circuit See Figure 3-3 for the internal main circuit structure of EM303B. Figure 3-3 Internal Main Circuit R T S 3.2.4 Standard Wiring of Main Circuit See Figure 3-4 for standard wiring of main circuit. 25 EM303B-0R7~015 U V W Mains Control Circuit Cooling Fan EM303B-018~30 R U S V T W Mains Control Circuit Cooling Fan EM303B-37~200 U V W Ma Fin as for Mains C Co irn ct uro itl n Cooling Fan EM303B-220~400 R U S V T W Control Mains Circuit Cooling Fan Mains Mains for Fan Mains