AC vs. DC
Published on Monday, March 28th, 2011 at 6:34 pm by Waco BoomDownload a Printable PDF of this Page
Waco Boom Co Ltd tests 100% DC on their fiberglass booms. They also have a HI-POT AC tester capable of 120kV AC testing. The reason we do DC testing is that it is a better indicator for our process. It measures through the wall of the boom and can detect voids (entrapped air and or water) better than the AC test does. Since Waco Boom does not usually have steel weldments in the bare fiberglass booms, the AC test gives an advantage.
AC testing typically detects sharp edges as corona or can also detect capacitance effect of large steel attached to one end. But through the fiberglass wall, testing is better evaluated with DC as we put a conducting ring and collecting ring on both the inside and outside of each end of the part.
By Bob Simon