International standards, such as IEC 62271-100 define recommended tests for circuit breakers condition assessment. Coil resistance, minimum trip voltage and mechanism charging time are the tests that are mandatory in order to assess the state of a circuit breaker´s auxiliary circuit. For these kinds of measurements, a coil tester is needed.
Coil testers SAT30A and SAT40A are powerful, lightweight (up to 10 kg) devices capable of testing coil resistance, minimum trip voltage and mechanism charging time. The typical application covers scenarios when substation battery is not connected or available. The SAT instruments are able to:
Unlike many devices on the market coil tester series of devices have a very low ripple (<0,5%), regulated output voltage and output current that is not load-dependable. Coil testers can even be used as a power source or a temporary battery charger. Output voltages range from 10 – 300 V (DC) and 10 – 250 V (AC).