Tag Archives: Hydropower

Heavy Duty Crane in Action

Why would you weigh a 225 ton power generation rotor unless you really have a good reason? The answer, the exact weight is very important to the safety of everyone working at the Beaver Dam power house.

A team of technicians and engineers from across the Little Rock District set-up scales to weigh a 225-ton power house rotor at Beaver Dam. Photo by Julie Ann Massey.

The in-house bridge crane system at Beaver Dam has a maximum rated lifting capacity of 450,000 pounds. According to the American Society of Mechanical Engineer guidelines, a crane is limited to two lifts in excess of the maximum rated lift capacity in a 12 month period. If the rotor and lifting beam weighed less than 450,000 pounds, the team in the Beaver Dam power house would be able to proceed with the rehabilitation of their bridge crane. The only problem…a mechanical drawing for the crane and beam stated the total weight at 455,000 pounds.

Team members closely monitor scale readouts during the rotor weighing process. Photo by Julie Ann Massey.

To guarantee safety, a team from across the Little Rock District was assembled to weigh the massive rotor. They placed four jacks within an 8 foot diameter around the erection bay pedestal to raise the rotor. This diameter keeps the load directly over the concrete column that was designed to support the tremendous weight. Scales were placed between the rotor and the jacks. The large bolts that attached the rotor to the pedestal were loosened. The rotor was picked up and weighed twice. The measured weight with the lift beam was 449,320 pounds, which is just under the crane’s rated capacity.

The team records the final weight – 449,320 pounds. That is just under the crane’s maximum rated lifting capacity of 225 tons. Photo by Julie Ann Massey.

Now that the team has an accurate measurement and the total weight is below 225 tons, the bridge crane rehab can proceed and the crane will provide years of safe and reliable service in the power house.

*  Photos and information provided by Julie Ann Massey, maintenance control specialist at Beaver Lake power house.