PMM1009 is an internal, high-speed metering auto voltage selection relay designed to allow automatic changeover from a primary 3-phase supply to a secondary 3-phase supply if any fault in the primary supply is detected. An alarm contact and front panel LEDs indicators are provided to ease fault diagnosis.
Also, a typical application as a voltage selection relay is the automatic connection of metering equipment to an alternative supply if the primary or preferred supply fails, or any similar application.
PMM1009 monitors the three-phase voltage supply and operates immediately if the supply is interrupted or becomes unbalanced due to failure of the primary or secondary voltage sources.
The recovery of the primary supply to a healthy condition will cause the relay to change back to the primary supply (if automatic mode for source 1 priority is selected).
The automatic recovery mode can be set by connecting priority terminals together. In case of manual mode, the user needs to press the reset button on the front panel to reset the connection to the primary source.
Front panel LEDs will indicate the status of sources and device operation and thus allowing fault recognition. The LEDs will be activated due to the following conditions:
