07-17-2015, 08:09 PM
(07-17-2015, 05:15 PM)turbo711 Wrote: Thanks Dallen and Edk. I am not familiar with this industrial wiring stuff. How do you guys know that they are the right ones? What is the difference between a CN or a CU prefix. I get the NO or NC aux relay thing, and the coil voltage, but what about the main contact arrangement? Can they be normally open or closed? If I get the exact replacement, then I can just wire it in, but if it is different, then I will have to figure out the complete circuit, and that would be a big pain.
Mark
Mark,
I looked at the datasheets for both the CN and CU versions and I couldn't see any difference. They are both 24VAC coils and 25A normally open contacts so there's no reason either one wouldn't work. The main contacts need to be normally open since the two contactors on the left are what switches the motor direction. If they were normally closed they would short out. See the attached wiring schematic from the manual for my lathe. That might help show the need for normally open contacts.
Ed