PWA01CM235A Carlo Gavazzi

PWA01CM235A, Control Relays and Protection Load Control for Three-Phase Systems Models DWA01, PWA01, PWA01CM235A, Precise Control Relays of cos φ, max. value or min. They measure their own supply voltage and the intensity of a three-phase load-balanced system. For the measurement of intensity the connection can be direct or by means of standard 5A current transformers and MI current transformers. LEDs indicate the status of the alarm and output relay., PWA01CM235A, These relays can be used to control the load of asynchronous motors. They measure the three-phase voltage and intensity of the L1 phase connected to an asynchronous motor. The relay measures the cosine of the angle between the intensity and voltage of the motor (cos φ). As the cos φ varies with the engine load, loads above or below the established limits can be detected indirectly by the DWA01 and PWA01 relays. The ratio of load to cos φ depends on the type of motor. As a rule to ensure correct working conditions, the maximum level can be set above (or below) the cos φ of the engine. It is recommended to make the adjustment after a practical test. The relay has a delay to the connection to prevent the detection of overloads during engine starting. Example 1: Maximum level control. The relay connects and the yellow LED stays on while the cos φ is below the selected limit. The relay disconnects when the cos φ exceeds the selected level. Example 2: Minimum level control. The relay connects and the yellow LED stays on while the cos φ is above the selected limit. The relay disconnects when cos φ is below the selected level Example 3: The DWA01CM235A and PWA01CM235A can be used to control the cos φ a single-phase load with a supply voltage of 208 to 240 WLA. In this case the supply voltage must be connected between L1, L3 (or 5, 7) and L2 and L3 (or 6 and 7).