A new type of monitoring relay from Carlo Gavazzi provides further protection for generators, by adding current flow measurement to conventional active monitoring.
According to Carlo Gavazzi, ensuring that current flow is within set limits averts overloads and prevents generators from acting as motors in highly overloaded three-phase systems.
New DWB03 and PWB03 are precise TRMS active power monitoring relays for three-phase balanced systems. They can be used to monitor the actual load of asynchronous motors and other symmetrical loads, as well as to check that power is flowing in the correct direction. Upper and lower limits are adjustable separately and can be set between -100 and +100 percent of nominal power.
Start/stop input allows the use of manual switches to start and stop the system, without the need of an auxiliary device. There is an adjustable 1-30s delay timer to prevent false alarms during start-up, and the devices also have a latch function allowing engineers to maintain alarm status even after the end of the alarm condition. Front panel LEDs indicate the state of alarms and output relays as well as the power supply.
In addition to active power measurement, the relays offer direct current input up to 10A. Moreover, they use the measured input to provide their own power supply, eliminating the need to provide a further auxiliary supply. Output capacity is up to 8A with
DWB03 models are in 45mm-wide Euronorm housings for DIN rail mounting, whilst PWB03 models provide the option of a 35mm plug-in module. All carry CE markings, IP20 environmental protection, and operate over a -20 to +60 degrees C temperature range.