Consultants specify liquid silicone-filled transformers at media manufacturing plant to increase efficiency and improve fire safety of this power delivery system.

When the San Francisco, Calif.-based engineering group Keller & Gannon specified silicone transformer fluid for six units installed at the new MMC Technology facility in San Jose, efficiency, low noise levels, and fire safety topped their lists of concerns.

Privately held by Hyundai Electronics, MMC is a manufacturer of rigid computer media. The new transformers supply power to offices, manufacturing, and R&D facilities. Because they are located in the center of the three buildings, noise played a big role in the engineer’s transformer specification.

“Liquid-filled units generate less noise and take up less space than dry types,” says consulting engineer Harjit Grover. “In addition, liquid-filled units have greater efficiency at 50% of the rated loads or less, which translates into significant savings.”

The complex relies on 2500kVA transformers, which are approximately 85 in. by 130 in. and 90 in. tall, supplied by Cutler-Hammer/Eaton. Each unit contains roughly 512 gal of 561 Transformer Fluid from Dow Corning Corp.

“The system is designed with redundant features in case of a sudden power loss,” says Cutler-Hammer/Eaton Senior Sales Engineer Jim Avery. “The transformers are paired off and used in a double-ended substation configuration, so if one transformer goes out, the other one can handle the whole load for that substation.”

Each of the substations consists of two transformers, secondary mains, tie breakers, and feeder distribution sections. In case of a power loss, there is also an on-site emergency generator.

When it comes to fire safety, the thermal properties of silicone transformer liquid provide an added measure of safety. In the less flammable dielectric fluid category, Avery says he prefers silicone over the hydrocarbon alternative because of its excellent fire properties. “Silicone fluid has a significantly lower heat release rate, and lower toxicity of combustion by-products than its competitors,” he says.

According to MMC facility engineer Jim Ferenz, liquid silicone-filled transformers also require less maintenance. “The thermal stability of the fluid can mean lower costs over the life of the unit,” he says. “In addition, the high clarity of the fluid will allow us to check for foreign materials at a glance. Less maintenance translates into lower costs.”

As with most liquid transformers, you can perform diagnostic tests on the silicone units to collect information about the condition of the transformer.

“From a maintenance standpoint, the ability to determine the status of the transformers through diagnostic testing was an added feature of the silicone-filled units,” says Ferenz.