Three single-phase, 7200 volt to 480 volt, 100 kVA transformers are connected in a step-down bank with the 7200 windings connected in wye and the 480 volt windings connected in delta. What is the rated line-to-line voltage on the wye side? 1. 12,470 V
2. 7,200 V
3. 4.160 V
4. 14,400 V
5. None of the above

Determine the time of the day and month of the year at which the peak sensible cooling load occurs for a top floor, north-eastern corner room of an office building in durban for the following conditions: floor area: 8 x 8 x 3 m east and north walls: 115 mm face brick (outside), 20 mm air space, 115 mm ordinary brick (inside) with 15 mm plaster roof construction: suspended plasterboard ceiling, 450 mm air space, 150 mm concrete, 75mm screed, waterproofing no heat transfer across other surfaces window area 3x 1,5 m high in north wall only. ordinary glass with venetian blinds. lights and occupants : from 07: 00 to 18: 00 average light density: 25 w/m2 number of occupants : 5 seated, light office work room temperature 24°c