Drive System

A problem with the new building drive where it frequently tripped its own earth leakage breaker was solved by installing a different type, as recommended by Siemens. Unfortunately another problem has prevented the installation, where the weather station fuse constantly blew-up when powering on the drive. This is believed to be due to an earth leakage somewhere in the mains power line to the station. After the lightning storm in February this 'leak' seems to have turned in to a permanent short circuit and it was not possible to power the station at all from the line going to the telescope. A separate line from the service building now provides the power and as a consequence this has also solved the fuse problem with the building drive.

A full mechanical test of the new building drive was made by installing one of the motors in the telescope building. We now know how to do this in detail and how much time it takes. The only thing remaining is to specifically schedule and execute the replacement of the drive system. As on earlier occasions we have taken care in having the old and the new system existing alongside each other and allow for a switch between the systems as fast as possible (though this is on the mechanical side still a few hours). In this way it is possible to do functional tests whenever required, and by the time we will switch over completely it will be possible to go back to the old system on relatively short notice. In the end the idea is to have the new system running for some time before removing the old system completely.