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The water exiting the nozzle is collected in a

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The water exiting the nozzle is collected in a releasing basin equipped with a triangular weir at the downstream end to allow measurement of the flow discharge. Energy is extracted from the turbine using an assembly comprising friction plates centered on the turbine shaft and a pendulum attached to them. Pendulum deflection is converted in torque applied to the shaft by a mechanical system. A gage located on the mechanical brake indicates the torque applied on the turbine shaft. Water is drawn from the pipe to the turbine for cooling the friction plates. A pair of hand-wheels is used to control the friction applied on the mechanical torque. The rotational shaft speed (rpm) is determined with a photo- tachometer. Procedures Measurements will be taken to determine the efficiency-rotational curve for two discharges. Each group of students will proceed with the sequence described below. 1. Close the two drain valves positioned on the releasing basin. 2. Open the discharge controlling valve on the inlet pipe and record the pressure on the pressure gage. 3. Loosen the torque brake so that there is no friction applied on the turbine shaft. Adjust the torque gage display to zero reading. For this setting the tachometer should reed a rotational speed of about 1800 rpm. 4. After the water level in the basin has become steady, measure the head on the weir ( H 1 in Figure 3) using the point gage located on the basin. 5. Measure the rotational speed of the shaft with no torque resistance on the shaft (runaway condition) with the provided tachometer. Carefully align the tachometer reading line perpendicular to the phosphorescent tape on the shaft. 6. Tighten slightly the friction hand-wheels and record the torque displayed on the friction gage as well as the rotational speed of the shaft with the tachometer. Note: As the hand-wheels are tightened, the mechanical torque is very sensitive to changes, in particular, for positions close to the fully stopped shaft. For these positions the torque gauge reading will oscillate by as much as 1.5 ft-lb. The best data are obtained by using gradually smaller increments on the torque as the fricition applied to the torque are increased.
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