Maintenance Planning and Control IENG 411 Case Study 1 Due Date: 20 March 2023 Cover-Shield Failure and Falling Incident at a Hydroelectric Generating Station Ontario Power Generation, located on a dam on the St. Lawrence River near Cornwall is the second-largest hydro power station in Ontario. It contains typical hydroelectric equipment such as turbines, generators, a repair shop (called the erection bay), and a 300-ton gantry crane (a moving, four-legged overhead structure). It is an outdoor type of generating station, where the 16 generators are located across the dam, side by side, and are easily accessible by the gantry crane. The crane is used to handle generators in need of repair. It moves on rails and can be moved into the erection bay. The erection bay is a closed structure near shore on the dam, with a huge door that can be opened to let the crane in. The door opening measures 20 meters by 20 meters. The door is powered by a motor. A drive shaft runs across the top of the door opening. The drive shaft has sections joined by three chaintype couplings (see Figure 1). The cast-aluminum covers that are mounted over the couplings (see Figure 2) rotate with the couplings as the drive shaft turns to operate the door. The coupling covers are made up of two sections. Each section weighs approximately 3kg. The two mating surfaces of the coupling cover sections are joined by two bolts. There are no nuts used. At approximately 11:00 a.m. on Saturday, October 30, 1999, a maintenance technician started to open the erection bay door from the in side push-button station on the south side of the door. The door had raised approximately 2 meters when he heard a noise at the north side of the door and saw something fall to the erection bay floor. He stopped the door and went to investigate. The technician found two halves of a driveshaft coupling cover and two bolts for securing the coupling cover on the floor. The coupling cover was from the north drive-shaft coupling. After the incident, the door was isolated. The coupling cover was bolted back on the coupling. Also, the covers on the two other drive shaft couplings were inspected. Two bolts on the south coupling cover had to be tightened 1/8 turn each. One bolt on the center coupling cover was tight and the other bolt had to be tightened 1/8 turn. The door was returned to service