If a hipot failure is encountered while the hipot tester voltage is ramping, the voltage read may not be completely accurate, as the display is refreshed five times per second. In this case, the voltage displayed could be lower than the actual failure voltage. For the most accurate results, automatic voltage ramp machines should be set for the slowest ramp rate. If the tester has a manual ramp, the voltage should be reset to zero for each test and the knob turned slowly for most accurate results.