Megahertz amp UPS power for RaceTech19 April 2011
The three new HD trucks being used by racecourse outside broadcast specialist RaceTech had particularly demanding UPS requirements that almost all the power supply specialists couldn’t meet, writes David Fox.
RaceTech is just about to take delivery of the third of its new HD trucks. The design of all the trucks is the same, but rather different to most other OB trucks thanks to the unique requirements of having to output several different broadcast and on course feeds, including one needed for regulatory use.
"One of the main challenges was finding [an uninterruptible power supply] that would fit into the space available and keep the truck running for at least 15 minutes, as they have to keep running for the duration of a race," explained Stephen Burgess, Technical Director of RaceTech’s systems integrator, Megahertz Broadcast Systems (pictured in the third truck). "Usually a UPS just has to shut down everything gracefully."
However, it was difficult to find a large capacity UPS that was compact enough. "We had a long hunt to find these UPS systems, as each alternative had problems with size and capacity."
They eventually found what they needed in England, from Borri, and Anglo-Italian firm specialising in high-efficiency UPS systems.
After much testing, they fitted three Borri UPS systems in parallel, all communicating with each other, so they can perform a redundant role. "You can afford to lose one of the three and keep the race on air," he said.
The Borri systems are relatively modular and fit in just six rack units (4U for the battery pack and 2U for the 6kVA UPS electronics), "so the whole lot filled up only 18U of space, and kept a 50 amp truck on air for 15 minutes," explained Burgess.
"The maximum capacity of the UPS system is 18kVA for 10 minutes. 18kVA is around 78A at 230V, so absolute best is 78A for ten minutes. There are power factor corrections to take into account, so that 78A current is reduced a bit for a real load. The technical load of the vehicle is only 50A and less current means the batteries last longer, so we are getting at least 15 minutes," he explained.
The UPS systems are from the Borri Rotation+ Series (so named because it can be set up in a tower or rack configuration – with the control panel rotating to stay the right way up).
There will be a complete report on the design and build of the three RaceTech HD trucks in the May issue of TVBEurope magazine.