870133 - Tweco 300A External Welding Contactor Switch

Industrial Grade Current Control

The Tweco Hefty Contactor, 300 Amp (870133) is a robust solution designed to bring modern functionality to traditional welding power sources. Many industrial engine drives and older rectifier power sources operate with "hot" terminals, meaning the electrode or wire is electrically live as soon as the machine is turned on. This presents safety hazards and limits the types of wire feeders that can be effectively used. The Hefty Contactor solves this problem by acting as an external switch, sitting in-line with the welding circuit to manage the flow of current.

Engineered for durability, this unit is rated for 300 Amps, making it suitable for a wide variety of medium-to-heavy duty applications, including MIG welding, flux-cored welding, and carbon arc gouging. When installed, the contactor keeps the welding circuit "cold" until the operator activates the gun trigger or remote switch. This not only prevents accidental flashes and arc strikes but also allows for the use of voltage-sensing wire feeders in a safer, more controlled manner. It is compatible with both Constant Current (CC) and Constant Voltage (CV) output machines, offering versatility across different equipment fleets.

Installation is straightforward, designed to integrate seamlessly into standard welding cable setups. The unit is housed in a rugged enclosure that protects the internal electromechanical components from the dust, dirt, and rough handling typical of industrial environments. For fabrication shops, field construction sites, and maintenance departments looking to upgrade their equipment's safety and capability without purchasing new power sources, the Tweco Hefty Contactor is the industry-standard choice.