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Grounding
Input and output ground points are provided, and hardware is also supplied. The locations are shown on the connection
diagrams and differ based on design, enclosure type and size. In most designs, the grounds are also identified by a label.
Control wiring
No additional control wiring is necessary for basic operation. See the example below. For ease of access, the control
terminal blocks can be unplugged for wiring.
24 V power supply (PS) and control transformer CPT
All bypass units have a separate 24 V power supply that provides control circuit power as well as backup power to the VFD
logic. This backup power feature allows the VFD logic and keypad to remain operational when the main input power has been
removed when the Isolation Contactor or Switch option is provided.
For 208/230 and 480 V models, the power supply is powered directly from the main 3-phase power. The 24 V power
supply has either a 3-phase or single-phase input.
575 V bypass models have an additional control transformer and fuses (FU8, 9 and 10) to step down the line voltage to
120 Vac. A single-phase 120 Vac input supply is used.
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