The Megger? FT4 Flash Tester operates from the mains supply and provides a continuously variable AC test voltage up to a maximum of 4 kV. The AC voltage frequency is that of the supply. A simple function switch permits the selection of one of the three modes of operation ?Breakdown?, ?Trip Level?, and ?Burn?. In the ?Breakdown? mode the instrument responds only to the high-frequency signals produced by the flashing arc of breakdown and trips the test voltage only when this occurs. In the ?Trip Level? mode, the output voltage is tripped when the pre-set threshold level of leakage current is exceeded or if the breakdown occurs. For the ?Burn? mode of operation, the output is maintained irrespective of leakage current or breakdown; the output voltage drops to limit the level of current flowing.   Leakage and breakdown failure are indicated by the illumination of the failed lamp and the sound of an internal buzzer. In the ?Trip Level? mode, the pre-set leakage current level is variable between 0,3 mA and 3 mA. Leakage current in all modes is indicated on an analogue meter.   In the ?Burn? mode, neither the failure signals nor the circuit tripping occurs, but the voltage drops to limit the current flowing during burning at the fault. The ?Burn? mode is provided to enable the point of breakdown failure to be located. As a safety feature, when the output voltage is tripped due to a failure in the test item, an interlock system keeps the voltage switched off until the circuit is manually reset by turning the voltage control to zero.   Test Voltage Range 0 – 2 kV and 0 – 4 kV a.c. (nominal) continuously adjustable APPLICATIONS The FT4 is designed for flash testing and a.c. applied voltage testing on electrical equipment, components, printed circuit boards, and general electrical machinery.