Limiter switching apparatus

摘要

A limiter switching apparatus includes a control box adapted for being mounted on a machine table with a plurality of terminals and indicators for making electrical connections; and an interface circuit device installed in the control box and electrically connected to the terminals and indicators for effecting switching operations. The interface circuit device is composed of a lower supply circuit for supplying minimal current and voltage therefrom, a first switching circuit connected to the power supply circuit for being actuated to turn on and off, a limiter switch circuit coupled with the first switching circuit and the power supply circuit for controlling the on and off of the first switching circuit, and a second switching circuit with a relay arrangement electrically connected to the power supply circuit and optically coupled with the first switching circuit for effecting relaying operations along with the on and off of the first switching circuit, thereby, safe switching operations with minimal current and voltage can be ensured without incurring electrical leakage from water and oil damage.