How to Maintain Mechanical Interlocking Systems

Functions

A source changeover system, either manual or automatic (ATS), enhances the continuity of service of an electrical distribution system.

Mechanical interlocking between the devices in the source changeover system prevents the closing of two devices simultaneously.

The use of mechanical interlocking for source-changeover systems using cables or connecting rods is compulsory for Automatic Transfer Switch (ATS) applications.

A mechanical interlocking system is made of the following parts depending on the type of Masterpact MTZ devices:

oAn interlocking plate on the side of each Masterpact MTZ device.

oA set of cables or connecting rods linking the Masterpact MTZ devices.

The figure below illustrates a mechanical interlocking system by cable for source changeover between two Masterpact MTZ2 devices:

 

 

Degradation Factors

The factors which can cause degradation of the mechanical interlocking system are the following:

oDusty or dirty environment

oVibration

Potential Hazards

Performing regular maintenance on the mechanical interlocking system can help to avoid the potential hazards and consequences listed in the following table.

Preventive Action

The following table lists the preventive maintenance procedures to be performed to maintain the mechanical interlocking system.

For more information, refer to Preventive Maintenance Programs.