Trayer Engineering's Tri-Phase Visible Disconnect System is now available with a ground position. A three-phase three-position knife blade switch is mounted in series with a vacuum load interrupter switch or a vacuum fault interrupter.
The operating handle of the visible disconnect with ground position is mechanically interlocked with the vacuum load interrupter or vacuum fault interrupter handle so that the vacuum contact must be opened first and closed last to make and break the loads within the vacuum contacts.
The tri-phase visible disconnect is positioned in front of a large viewing window on the switch tank surface to provide a clear view of all three contacts in the closed, open and grounded position. The newly designed padlock provisions provide the utility with many safety options. Two separate padlock provisions allow for a supervisor’s padlock to be installed to prevent the device from being grounded without first removing that padlock. The second padlock provision allows an operator to attach a lock to the device handle in the open or grounded position.
The visible disconnect with ground position addresses operation and safety concerns of vacuum equipment on many levels. The use of two devices in series facilitates the maintenance-free design of vacuum load break switching and eliminates the need to remove 600 A elbows for testing, isolating or grounding cables. It provides quick, reliable and visible verification and grounding while eliminating the potential for contamination to the elbow bushing interface. Now you have the advantage of vacuum contacts with thousands of transient-free load break operations, requiring no maintenance, along with the added safety of the BIL across the visible disconnect and the convenience of internal grounding. Overall labor costs and outage times can be greatly reduced, while increasing the reliability of the entire circuit.