1 or 2 dedicated 120VAC circuits for my CNC?

The coil diagram looks a little odd because they've drawn a flyback diode as well.

Apparently this particular relay includes...

• LED indicator for monitoring operating status and diode surge suppression for limiting voltage spikes

Not sure if that is good or bad in my situation? I assume it should work fine?

It's good in every situation.  LED is optional but nice, diode is required in many cases to protec whatever is triggering it (i.e. Mesa).

Notice how the Fuji rated current drops with the rise in voltage, Eaton does not.

Yes I noticed that and was curious why? So is your take on it that they are not posting accurate numbers? I see this all the time with Chinese stuff but I was under the impression that Eaton was a pretty good company.

Since we are on this subject can you guys give me your opinion on which companies are the better ones to look for in the electronics industry? Here are some of the brands I see all the time, at least in the relay/contactor category. If you have others that you would recommend that would be great. 

• Dayton
• Schneider
• Eaton
• Fuji
• Allen Bradley
• GE
• Siemens
• Sprecher + Schuh
• WEG
• Omron

Since you are using a single phase, you can always parallel relay contacts for more current.

That is interesting. So does this double the current, or is there a calculation to determine what it would be?

Thanks

My opinion - subject to change if Tommy tells me I'm all wrong...image missing /media/kunena/emoticons/wink.png

All the companies listed are fine.  Some are significantly more expensive when new than others.  And there are plenty of other 'top-tier' or nearly top-tier component OEMs.  I'm sure there are dozens I've never heard of, much less used or seen.

You want another rabbit-hole homework assignment?  Go to HGR Surplus's site, and search for "enclosure" or "control" or similar.  They've got tons of used industrial electrical & electronics stuff, and if you zoom in on the photos you can start to get an idea of what people use when money is no object.

Look at the CNC machines and other automation equipment and check out the close-ups of the control cabinets.  Ignore the drives & VFD's - look at the relays, contactors, power supplies, and other 'commodity' components.

Same thing for motion hardware.  Hi-win linear rails appear to be the cat's meow in the hobby/printer world compared to no-name ebay stuff... but you won't find them in frequently in industrial equipment.  THK, Bosch-Rexroth, IKO, Thomson Linear, and others never found on a 3D printer.

Keep in mind that the brands you come across are regional.  Lots of Allen-Bradley over here, Siemens, AB, & others in Europe.  Mitsubishi Electric for Japanese equipment.  It varies, and some equipment manufacturers stick with suppliers they know even if they could save money with a perfectly good substitute.

Sray69 wrote:

 

• Since you are using a single phase, you can always parallel relay contacts for more current.
  That is interesting. So does this double the current, or is there a calculation to determine what it would be?
  
  Thanks

That one's beyond me.  I don't know if I've ever seen a rating for individual contacts or how the rating is determined.  Is a "20A" contactor good for 20A per contact, or 20A shared between all three (or 4 or 2)?

Good question.

@ Spumco,
You forgot NSK!
They are top tier for linear rails and ballscrews, still made in Japan.
I see them on really expensive machines made to run 24/7/365.
THK seems to be on paar with them.
Yes, you can parallel relay contacts, and they are rated for single contact current.
Many plasma cutters use paralleled relay contats to switch the high current on and off, always when pilot arc is HV or HV/HF.
@Sray,
All the manufacturers you mentioned are good, except Dayton and Eaton that i never used or seen used so for those Spumco is a much better refference since he has experience with them. Of the rest Schneider is a bit cheaper, Omron is top notch, i have used propably over 500 Omron relays by now, even used ones never fail.
The issue with relay contacts and current/voltage ratings is the ability to switch off and prevent arcing. High current/voltage relays and switches have built in arc suppressors.
Not an issue with home voltages and currents. And as a general rule, all of those will work with a bit higher current than rated, just do not push them to far. I would guess 20% more current is OK, but it will shorten the contact life span, probably by quite a bit.