Two main coils are wound over stator core. Each main coil outputs half the rated power at the lower voltage (120V). These main coils are wound to be in the same phase. The full power switch reconnects these main coils in parallel or in series.
Fig. 5-12 shows a circuit diagram. When the full power switch is set for single lower voltage indication (120V), the switch position is as indicated by the lower solid line in the diagram. Fig. 5-13 is a simplified representation of this circuit, showing the two main coils connected in parallel. In this case, the higher voltage (240V) at Rec. 3 cannot be taken out. Rec. 2 for the lower voltage can output up to the rated power (up to 30A if the rated current is over 30A), and Rec. 1 can output up to a total of 15A.
When the full power switch is set for double voltage indication (120V/240V), the switch position is as indicated by the upper dotted line in Fig. 5-12. Fig. 5-14 is a simplified representation of this circuit, showing the two main coils connected in series. In this case, power can be taken simultaneously from the receptacles for the both voltages. Rec. 3 for the higher voltage can output up to the rated power, but Rec. 1 and Rec. 2 for the lower voltage can output only up to half the rated power each.
Table 5-4 is a summary of the above explanation. Select the proper output voltage by full power switch in accordance with the appliance to be used.
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