Figure 7-45. - Four 115-volt coil connected in parallel for 230 volts; each coil still receives only 115 volts.
supply. Each coil receives 115 volts. If the four coils were connected in two parallel sets of coils to a 230-volt line, as shown in figure 7-45, each coil would still receive 115 volts. So, regardless of the line voltage, the coil voltage is the same. This is the principle used in all dual-voltage machines. Therefore, if four leads are brought out of a single-phase motor designed for 460/230 or 230/115-volt operation, the motor can be readily connected for either voltage.
When you are connecting a dual-voltage wye motor, remember practically all three-phase dual-
Figure 7-46. - Terminal markings and connection for a wye-connected dual-voltage motor.
voltage motors have nine leads brought out of the motor from the winding. These are marked TI through T9, so that they may be connected externally for either of the two voltages. These are standard terminal markings and are shown in figure 7-46 for wye-connected motors.
HIGH VOLTAGE. - to connect for high voltage, you should connect groups in series, as shown in figure 7-47. Use the following procedure:
1. Connect T6 and T9; twist and wire nut.
2. Connect leads T4 and T7; twist and wire nut.
3. Connect T5 and T8; twist and wire nut.
4. Connect leads TI, T2, and T3 to the three-phase line.
LOW VOLTAGE. - This same motor can be connected for low voltage. Use the following procedure:
Figure 7-47. - Two-voltage wye motor windings connected in serifs for high-voltage operations.Continue Reading