Need help with electric company flash off and on power

[Harold Hallikainen]

I knew the people who started one of the early UPS companies (Cuesta Systems). Some of their smaller UPS systems did not include a provision for external batteries because a longer run time would cause them to overheat (and not pass UL testing).

[Mark Gulbrandsen]

That's pretty cool Jim! The only similar thing I've seen like that was in the downtown Chicago theaters where they brought in the usual AC feed plus a DC feed that came from various Elevated train power plants. The DC had to go through huge resistor ballast and then to each arc lamp. At another neighborhood theater, they used 440, or was it 480?? volt AC rectifiers and had a feed for that. And then the usual 220 three phase... This was all 30+ years ago...

[Harold Hallikainen]

...
When I was sent to San Antonio
for DUNKIRK a couple of years ago, the large modern multiplex theater complex they had
me working at got it's power from two separate substations, since power interruptions and
outages were quite common during the huge thunderstorms they get in that part of the
country.

That's pretty amazing! Some broadcast transmitter sites get power from two separate feeds, one going up one side of the mountain and the other up the other side.

For a theater to get power from two separate substations, were they right on the border of the area covered by each? Or did they have to run HV lines to another neighborhood to get a feed from another substation?

Harold

https://w6iwi.org

[Mark Gulbrandsen]

Harold... At Farnsworth Peak in Utah, they only had one massive AC feed up the west side of the mountain. That of course was lost one winter and it was off for 3 weeks. They had a massive Battery Back up system as well as an almost 1.2 MW diesel generator. and enough fuel to run it for 48 hours. While the main AC feed was down they had to get a tanker truck up the winding road every couple of days. This actually required a sizable crane to follow the fuel truck up, and then back down to lift the rear of the tanker so it could make the curves. I think they said it was a 6 hour trip each way. Here is a link to a start up video I shot of that 3000 HP generator a number of years ago. It ran all 8 DTV transmitters.

https://youtu.be/0_c0OgHRrZE?si=-hhD2zw-q4X0Qdtp

[Jason Speers]

How about trying a UPS designed for AV stuff for each projector? Not too pricey and could give you enough juice to keep the lamps on during those quick outages. Might save you the hassle without costing a fortune.