geniusintraining
Lifetime Supporting Member + Moderator
I've seen people do this before too but probably only on lighting contactors at 120V. Is the concern with manually operating a 400 or 600V motor contactor arc flash?
Yep, I saw one guy do it on a reversing motor, the PLC would wanted to move the damper to the close limit switch, he pushed in the open starter, when the PLC saw the damper off the limit it pulled in the close starter and this sent power to the forward and the reverse at the same time.... POW! lucky he only ended up on his *** and not really hurt.
Saw another guy push in a break contactor on a motor that was larger than me and the load went into free fall and caused the machine down for weeks and about 100k worth of damage.