Electronic load features a constant current mode
Saelig Company has introduced the Model PT04-FC 3kW Electronic Load which has been specifically developed to accommodate the testing of fuel cells as well as low voltage power supplies, including 24V telecommunications power systems and supplies. The load is simple and intuitive to operate and is housed in a 4U 19" rack-mount case, with two quiet temperature-controlled fans mounted on the front panel to provide forced air cooling.
The rugged, reliable design of the PT04-FC provides Constant Current control from 0-120A on the 24V range setting and 0-60A on the 48V setting, with constant power, constant resistance, and constant voltage also available as standard operational modes, accessible via ATE/remote control. Weight has been minimised for easy transportation.
The Model PT04-FC is also useful as a general-purpose variable electronic load. It is rated to operate continuously over the specified current and voltage ranges. The standard model offers a differential 0-5V input for simple control systems, or the input can be paralleled for larger systems.
A typical application might consist of an external DC power source to be tested (e.g. an individual battery, or battery pack, a power supply, or a telecomm rectifier) connected to the PT04-FC's DC power connectors, with the Remote Control Box connected to the load. More than one PT04-FC load can be connected in parallel.
The standard CP, CR and CV modes are realised by the use of an analogue processor circuit between the differential amplifier and load control circuit. This processor measures the DC input voltage to the load, then generates a current demand which gives the required level for the power, resistance or voltage that has been demanded.
The Mode control may be changed even while the load is sinking current, for which the PT04-FC has built-in protection. An over temperature alarm monitors the heat-sink temperatures; if a pre-set limit is exceeded then an alarm sound is emitted, the fault output line is activated, and the load current is clamped to 0A until the heat-sink temperature has reduced sufficiently.