I'm seeking to better understand the workings of a Square D medium voltage MCC by reviewing the schematics. It operates the attached motor on 3-phase 4160VAC.
Since the unit also needs 120VAC single-phase power to operate the control circuitry (relays, monitoring equipment, etc), there is a transformer, CP1, as shown below, to output 120V from 2 legs of the 3-phase supply.
In the snippet below, you can see the drawing of the 4160 to 120 VAC transformer. I don't understand why the 120VAC secondary side is drawn as two windings in parallel, with X2 and X3 cross-connected to the opposite 120VAC legs, instead of a single winding. What is the benefit of this configuration? Is it higher current output, less heat, or maybe just the only schematic the designer had handy in his CAD software :) ?
Disclaimer: I would never venture to work on any medium voltage equipment. We have EEs and qualified technicians for that. I work with low voltage control signals only. I was perusing the schematics to understand some control wiring (low voltage) associated with this MCC. I have no experience or qualifications in medium voltage work but was just curious when I ran across this in the schematics. It never hurts to understand more than you need to for your job.