Patent attributes
A sensing and switching device, such as an overload relay, is provided which includes a processor configured to make measurements and control operation (e.g., tripping) of the device. The processor regulates measurement of voltage and/or current, and the supply of power to power supplies. The power supplies store charge to provide operational power for the processor and that can be used for tripping and resetting contacts within the device. The processor opens a burden resistor measurement circuit when charge is being stored in the power supplies, and opens switches in the power supplies while closing the burden resistor switch to permit measurements. By alternatively switching for charging of the power supplies and making of measurements, the processor is able to reliably make measurements, control the device, and store sufficient power for operation of the device despite a demanding power budget.
