Payne & Dolan, a Wisconsin paving contractor, easily moves conveyors and other electrically powered processing equipment from one site to another at its aggregate operations, thanks to recently installed plugs and receptacles, which feature a contact technology that helps make power connections durable, safe and easy. The Meltric plugs and receptacles incorporate spring-loaded, silver-nickel, butt-style contacts that provide improved electrical performance over thousands of operations. In addition, they reportedly are resistant to wear, corrosion and other factors, which can contribute to premature failure of pin- and sleeve-type devices.

Headquartered in Waukesha, Wisc., Payne & Dolan produces asphalt pavement services and products. It owns and manages company-operated asphalt plants and aggregate sources, which gives it control over the product and ensures that its customers receive the best material for their specific needs.

At one of the company's quarries, a trailer-mounted 725 kW Cat diesel engine provides power for portable crushers and conveyors through a power distribution panel. Previously, connections between the panel and mobile equipment were made using pin-and-sleeve connectors, which were difficult to connect and disconnect. “Sand would get in the threads, so it was very hard to pull them apart. All it takes is a little bit of fine grit and you simply cannot use them,” explains John Schreurs, the company's master electrician.

Since converting to the Meltric plugs and receptacles, Schreurs has found that connections are easy to handle. “They simply twist and lock, so we don't have to worry about threads at all,” he notes. “The twisting wipes the contacts, so they are self-cleaning, which is a big advantage in our dusty environment.”

The quarry produces washed stone and sand, using three portable crushers and two large permanent crushers. Material is transported via several troughed belt conveyors, which include a 1,000-foot unit, as well as a 500-foot and several 250-foot conveyors. Jaw crushers and portable conveyors alike are connected to the distribution panel.

“We add conveyors and keep following the material until we get to the property boundary lines,” Schreurs says. The ease of disconnecting and reconnecting with the Meltric devices speeds up and simplifies the moves. They are used on all crushers, screens and conveyors at the site except for the few that are hardwired and not moved.

Disconnecting power to equipment is initiated by pressing a pawl on the Meltric receptacle, which causes it to break the circuit and eject the plug to its rest position. Then, a simple quarter-turn of the plug allows it to be easily and safely withdrawn from the receptacle, since the circuit is dead already. When the plug and receptacle are separated, a safety shutter prevents access to live parts and a lockout hole on the plug facilitates lockout.

Payne & Dolan's power distribution trailer is set up to provide flexibility and keep operations running dependably. “Everything is powered through the distribution panel on the trailer. Before we set it up with the generator and distribution panel on the same trailer, we had to find another way to get power to the equipment if we had a problem with the generator. Now, we can just pull the power unit off and put a different one in place so we can get back up and running,” Schreurs explains. Once again, the ease of disconnecting and reconnecting helps minimize downtime.

Easier Moves for Portable Crushing Plant

Another application is a portable crushing plant that the company moves frequently to temporary jobsites. In recent months, it was set up to crush recycled concrete near a repaving project. “We've moved four times since spring,” according to a company official at the site. The plant has been used to crush limestone and provide crushed aggregate at asphalt plants in addition to the concrete. According to Payne & Dolan, it takes about eight hours to set up the plant at a new location. The ability to make the many required connections quickly and easily helps get the plant up and running faster than when pin-and-sleeve connectors were used.

In all the company's applications, the Meltric plugs and receptacles provide greater safety due to their dead-front construction and enclosed arc chambers. Easily accessible contacts on the previous connectors had the potential to expose workers or others to live power, so switching to Meltric devices also helps ensure worker safety.