Vacuum circuit breakers are usually tested for defects using a DC hipot. However, a high field emission current flowing from an invisible needle-like spot can give false results. A better way to test a vacuum circuit breaker is by using a vacuum bottle tester.
Vacuum circuit breakers offer the advantage of interrupting large currents in a short time. This is possible because only a small gap is needed for the contacts to interrupt a large current. The vacuum provides a good environment to extinguish arcs because of the absence of air. Arcs usually form because of air becoming conductive due to ionization. Regular testing should be done to ensure the circuit breakers are within its rated limits. One of the most popular testers is the Vanguard VBT-60 60 kiloVolt tester. It has a variable voltage output of 10 kiloVolts to 60 kiloVolts with 5 kilovolt increments. It displays the test results in its back-lit LCD screen for easy readability. Because it is portable, it is ideal for substation and field testing.
You can rent the Vanguard VBT-60 vacuum bottle tester through Protec. We offer Vanguard testequipment and testing tools from other popular brands. Contact us if you have inquiries about our rental deals.