Hey guys, we are steadily working on our retrofit here and honestly we had a plan in mind to wire up the machine using some of the existing relays and contractors with the estop circuit and were moving in that direction. Well yesterday when I calling Wolf Automation on the phone to discuss a relay I needed and see about some wire consolidation pieces the engineer I spoke to on the phone told me that with the new drives and all of their built in protection and overload features as well as built in estop circuits and other niceties that they don't even bother anymore with supply line contractors and switching relays and just wire everything into the main disconnect on the back of the machine. I have heard this before and know of at least one other machine that was retrofit this manner. Basically that machine had a charge pump and my setup will include the mesa cards which utilize a watchdog feature that can work similarly apparently. The Teco Westinghouse drives as well as the Hitachi drives I have all seem to have alarm,E-stop,as well as enable signal inputs on them. After speaking with the tech support Guy and seeing my friends machine setup in this manner I am leaning towards doing it this way. The fellow told me that the mechanical relays switching as well as the contactors and their associated wiring can be the source of noise as well as potential problems. He basically said that everything that we were putting on the frontend there is already built into the drives and is not necessary anymore. Assuming that power is indeed removed from the motor leads coming out of these drives do you guys feel this is accurate and more importantly a safe wiring practice. I mean at the end of the day if the kimchi hits the fan I have the main machine disconnect as well as the disconnect located on the wall near the machine. Have any of you guys ever seen or done a build in this manner? Thanks and peace ....
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