General Hi-Pot safety information
Routine safety testing of transformers involves applying dangerous high voltages (up to 5500V AC) between primary and secondary connections of the transformer. This is the function of the AT3600's HPAC test.
The AT3600 transformer tester is a sophisticated device with multiple control and protection circuits.
There are three safety features that provide operator protection at the end of an HPAC test:
1. At the end of a test the HPAC voltage is ramped down in a controlled manner - not simply switched off. Controlled ramp-down ensures that the supply voltage is removed when both voltage and current are near zero. This process takes less than 2 cycles of the programmed test frequency (e.g. 50Hz)
2. The safety interlock system of the AT3600 must be present and in a "safe" state during any test. The recommended safety system is a light curtain made by Banner Engineering. If, for example, the safety system detects an operator attempting to handle the transformer under test before the test has finished then the test voltage is ramped down and made safe as above. The voltage is made safe quickly in accordance with international machinery regulations such that the part under test is at a safe voltage before an operator can touch it. The safety interlock also removes input power from the generator circuits such that no further high voltage can be produced, even under fault conditions.
3. In order to prevent operator injury and to ensure the long life of its relay matrix, the AT3600 is continuously monitoring both voltage and current. In the unlikely circumstance that normal ramp-down fails AND the safety interlock system is at fault then then the AT3600 will display "DANGER" and sound a warning buzzer. (This is a report of a fault condition and the fault must be corrected before resuming operation).
In all cases, installation, operation and maintenance of the AT3600 must be in accordance with the latest user manual. When correctly installed together with an appropriate safety interlock system then the AT3600 provides operator safety in accordance with international standards.