The JOULE PISTON RETARDER is a self contained hydraulically operated device, that requires no external power source. The unit is calibrated on a hydraulic test bench to pre-determined flows and pressures, as calculated on a Retarder Simulator, to ensure accuracy. All calibration is done under strict quality control. The simulator ensures that the efficiency of all setting parameters are maintained at all times during the final assembly and calibration of the retarder. As with all piston type retarders, energy extraction is speed related. Thus, higher railcar speed equals higher energy extraction.
All calibration is done under strict quality control. The simulator ensures that the efficiency of all setting parameters are maintained at all times during the final assembly and calibration of the retarder. As with all piston type retarders, energy extraction is speed related. Thus, higher railcar speed equals higher energy extraction. When a retarder setting is given as, for example, 4mph (1.80 m/s, 6.4km/h) – 1180J, this means that at 4mph (1.80 m/s, 6.4km/h) this retarder will extract 1180 Joules of energy from the railcar. As energy cannot be destroyed, but transferred from one form to another, and from one body to another, the extracted energy is transformed into different energy forms, such as heat, sound, vibration, etc.
The retarder has a speed sensitive valve, which is activated at predetermined speeds only. Thus when the railcar travels at speeds lower than the set speed, the valve will not activate, and the retarder “idles”. During idling no significant energy is exchanged, and energy of below 40 Joules is expected. This is extremely important for light cars traveling through.
In the event of the rail car traveling at a speed higher than the set speed the valve will activate and resultantly the retarder will extract energy from the car.