Problem 8
A facility electrical system includes an 800 A, 480/277 Main Distribution Panel, a 150 kVA
dry-type transformer, and numerous subpanels. The largest recorded demand on the
main distribution panel is 442 A at a 0.95 lagging power factor.
A 225 A, 208/120 V subpanel is devoted to critical loads in the facility. The largest
recorded demand on this subpanel is 190 A at a 0.75 lagging power factor.
What size backup generator (in kW) should be selected for this facility?
Select the best option from the standard sizes listed in the lesson slides. The best option
is the smallest generator that will meet the observed demand of critical loads.
Problem 9
A 60 kW backup generator is installed to support a facility. It will connect to a 480/277 V
subpanel through an Automatic Transfer Switch. The power factor of the subpanel
varies between 0.75 lagging and 0.95 lagging.
What rating Automatic Transfer Switch (in A) should be selected?
Select the best option from the typical sizes listed in the lesson slides.
