Friday, September 21, 2007

Silicone Insulators Replacing Ceramic

Dow Corning has suggested using silicone rubber in high voltage insulators rather than traditional ceramic materials or organic composites. Silicone rubber's non-conductive chemical composition makes it a natural insulator, but it is silicone rubber's exceptional hydrophobicity -- the ability to cause water to bead on the surface of the insulation -- that sets silicone apart.

"Silicone prevents moisture from mixing with contaminants on the surface of the insulator, even after long-term exposure to electrical discharge, pollution, weather, and ultraviolet exposure," Kristen Mizell of Dow Corning said. "This helps reduce current leakage and flashovers, reduces maintenance, and extends service life."

Silicone rubber composite insulators do not require any cleaning under any environmental conditions and can even suspend maintenance for more than 10 years.

Ceramic materials and organic composites start out with good hydrophobicity, but over time electrical discharges can erode and damage the insulating material, leading to failure of the insulator, Mizell said.

Tuesday, September 11, 2007

Universal High Voltage Test System

Find weak cables without making cables weak!

HVA60 manufactured by HV Diagnostics is a four in one Universal High Voltage Test system. "There is no need to carry two pieces of equipment around and then interconnect them!"

Apart from the variable frequency VLF output, the operator can also select dual polarity DC and cable jacket or sheath testing outputs modes.

The HVA60 model is capable of testing 1µF (Approx. 10,000 ft/ 3 000m of cable) at 0.1Hz and 62kV peak. The frequency or voltage of the output can also be reduced allowing even larger capacitance loads to be tested - at 0.02Hz, approx 50,000 ft / 15,000m of cable can be tested.

For more information, see