Universal test rig for pumps and turbines
This test rig is designed for experimental investigations of pump and turbine models in a closed loop. The main parts of the universal test rig are the headwater and tailwater vessels, the pipe system with the valves, the supply pumps, the span field and the steel structure for the model machines. The closed loop is cooled by a plate heat exchanger to ensure constant conditions during the experiments. For cavitation tests the absolute pressure level at the low pressure side of the model machine can be regulated from 40mbar to 6 bar absolut pressure by using a vacuum pump and compressed air. The test rig is equipped with a motor generator (Pmax = 400kW, Tmax = 2500Nm and nmax = ±0 − 3000min^-1) and a full size frequency converter for a 4-quadrant drive to adjust the runner speed. A hydrostatic bearing unit is used to consider the torque losses due to friction in the shaft bearing and to determine the runner torque and efficiency. The axial thrust is measured at the bearing unit also.