VFDs used in many manufacturing and industrial environments control the speed, torque, direction and horsepower of motors. When disconnecting power at a low frequency, excessive heat build-up can potentially cause damage to the switch contacts, preventing the disconnect switch from properly and safely cutting off motor power. Proven through extensive testing, Hubbell’s early break auxiliary contacts wired back to the VFD can prevent any damaging low-frequency current from reaching the switch. In evaluating other manufacturers’ early break contacts, not all had the same level of performance.
“We are excited to offer this new disconnect switch that improves safety when used with variable frequency drives,” says Brooks Challenger, Senior Project Manager for Hubbell. “When the CIRCUIT-LOCK handle is turned to the 15-degree position, a signal is immediately sent back to the VFD before the switch can be fully opened. This signal takes the VFD out of a potentially damaging low-frequency state.”