The UPS system covers our main systems (except the telescope cooling) and is activated in case of an external power failure. The direct loss of power is covered by a set of batteries, while normally the generator will start and provide electrical power until the mains is restored. If for some reason the generator fails to start we will only have power from the batteries which run out after about one hour. If the UPS power fails this can have serious effects, especially on our computer system that would power-down in an uncontrolled way.
We actually had a case during a power-cut where the generator did not start, and it was only because somebody noticed the lack of noise that this was discovered. To detect if we are running on batteries when the power is cut, a system had been made that uses a combination of a power usage monitor that records the output from the generator, and a signal from the TCS that detects when the external power has been cut. The system sends alarm emails in case the generator does not start within a given time. This is only a temporary solution, and a proper system needs to be defined and implemented.
A more general issue is that our UPS is ageing. We have obtained some cost estimates for the parts that need replacing. These parts are fairly expensive, and we are considering buying a new UPS unit. It should be noted that the existing system is rather over-sized if one does not include the cooling system (which actually can not be maintained running even by the existing UPS). Therefore, we are considering buying a completely new unit which is smaller but covers our needs (excluding the cooling system). Such a new system has a similar price to buying the new parts for the existing system, while the new system will be more efficient, so a bit cheaper to run. On top of that, it should be possible to maintain the current battery bank which should lower the price significantly. We are looking for the specific system that would cover our power needs (including the new emergency ventilation system we want to implement [see below] and that will be supported by the new UPS), and would be able to use the current battery bank.
Thomas Augusteijn 2013-05-10