Terasaki Automatic Transfer Switches

The most important input of a transfer switch is its switching mechanism, and TERASAKI ELECTRIC manufactures different types of mechanisms that can be used to produce this equipment, either manual or automatic type:

  • Molded Case Circuit Breakers (MCCB), from 125 to 2000 amperes.
  • Air circuit breakers (ACB), from 800 to 6300 amperes.
  • Contactors, from 9 to 800 amperes.

Depending on the application, different mechanisms can be chosen:

Switch/Molded Case Switch:

  • Link type mechanical locking: used between switches of the same frame (size), motorized or single, with the possibility of combination between 3-pole and 4-pole switches at the same time.
  • Cable type mechanical interlock: used especially when interlocking between breakers of different frame (size) is required.
  • Front mechanical interlock: designed for use in manual mechanisms that do not require automation.

Air break switch:

  • Key interlocking: using less key than the number of switches, an effective and reliable interlocking can be achieved effectively and reliably
  • Cable interlocking: system of cables or rods that simultaneously maneuver 2 or 3 switches, horizontally (fixed and withdrawable types) and vertically (withdrawable type only). Can be combined between any size of the ACB range.


A system of two contactors can be interlocked using a mechanical interlock, whereby both devices are prevented from being operated at the same time, which, together with an electrical interlock using its auxiliary contacts, provides the greatest reliability to the system.