Direct On Line Starter Control Circuit

Reminds me of back in the stoneage (at least it feels that way sometimes) when I was an electrical apprentice in a very large factory. Virtually all switching was done like this where the switch momentarily carried through the full current to operate the relay solenoid. A large portion of my work was to dismantle, clean, repair and replace these (mains voltage) switches/relays. Lashings of Carbon Tetrachloride to swill them, and a file/emery paper etc till the big copper contacts were ok...then perhaps new springs or new plated contacts before considering a whole new switch. Some of the switches were small but many were large...operating machines which turned armatures as large as this room, whilst other switches were sometimes up in the shop floor crane which carried those armatures over our heads. Transistors were making an appearance, but not yet in this environment. It's possibly why I am so fascinated with mosfet switching these days....never thought of that till now.

Refered to as 3 wire control logic. The push buttons create a fool proof electrical interlock, the stop button is the first logic function and bypasses all other functions.

http://everycircuit.com/circuit/5281605908430848