Just over a month ago we posted a video of our generator and transfer switch running through the self test process. These two videos show what happens in the UPS room when the transfer switch does its thing. But what happens with the UPS? The first video shows the corresponding UPS actions when the transfer switch moves from utility to generator.
The UPS will go to battery briefly as the transfer (although we don’t see any effect in the room lights) is enough to be momentarily out of tolerance. This is good: the transfer switch will reconnect under minimal load, extending its life and reducing the risk of a contact becoming fused. The generator test runs for an hour, so after that hour is up the transfer switch moves back to utility power from generator. This second video shows the actions of the UPS during the second half of this process.
As you can see, we perform a true test of our emergency power systems with confidence in its operation since a utility outage is identical to our test procedure. During a real utility outage the only major difference is that the UPS would run on battery from 10 to 20 seconds longer while the generator goes through its self start procedures before a transfer.