FADAL TRM - Control Cabinet Wiring Advice

[tblough]

I concur with the last few responses as well. Since the goal is to protect the motor, one fuse/breaker per motor. Fuses/Breaker should be sized to the max current the MOTOR will draw + 10%-20%. Wire size should then be selected to carry AT LEAST the breaker rating.

I normally have one main breaker after the machine disconnect. Wires coming in and going from this breaker are sized to carry the full breaker rating. This is then split to individual breakers for each motor driver, sized as above, and possibly other fuses for ancillary equipment. All of these breakers are fed with wire rated to carry the main breaker rating, and leave with wire rated to carry at least the current of the preceeding rated fuse.

[martyscncgarage]

I concur with the last few responses as well. Since the goal is to protect the motor, one fuse/breaker per motor. Fuses/Breaker should be sized to the max current the MOTOR will draw + 10%-20%. Wire size should then be selected to carry AT LEAST the breaker rating.

I normally have one main breaker after the machine disconnect. Wires coming in and going from this breaker are sized to carry the full breaker rating. This is then split to individual breakers for each motor driver, sized as above, and possibly other fuses for ancillary equipment. All of these breakers are fed with wire rated to carry the main breaker rating, and leave with wire rated to carry at least the current of the preceeding rated fuse.

Thanks for the input Tom. Because of the relatively small size of the drives/motors, I am leaning toward one pair of fuses for the 3 drives as Marc suggested. But not out of the question to go with 3 breakers....I just like fuses because they are quick acting but definitely inconvenient for the user to replace.

[slodat]

I've had good luck finding the Eaton FAZ-NA UL 489 breakers for a good price on ebay. I choose breakers because fuses aren't available here should one go.

I appreciate this thread. Thanks guys!

[martyscncgarage]

Continuing this discussion more. I see that Automationdirect.com has what they call as "Supplementary Protector" breakers by Eaton. I imagine these are downstream breakers from main overcurrent protection. For example:
https://tinyurl.com/teha75s

I noted they have 3 trip curves and are described in this cut sheet:
https://cdn.automationdirect.com/static ... tonfaz.pdf

Comments on the breakers for protecting Drives and comment on "trip curves"? I note they are rated UL 1077 where in the cut sheet they show UL489 for a motor. I assume this applies to the servo drive and motor as well.

The breakers themselves are pretty inexpesive...
Marty

[cncsnw]

I use the UL489 breakers from Eaton, as described above by slodat, for servo drives and inverters (as well as for across-the-line starters).

I base this mostly on NFPA79 7.2.10.1, "Each motor controller and its associated wiring shall be protected as an individual branch circuit...". I interpret that to mean that branch-rated protection (and not just supplementary protection) is required.

However, I could be reading too much into it. You certainly don't have to look far to find professional panels that are not built this way.

[BASE]

I used the Eaton UL489 breakers in mine as well but it’s not running yet. I remember someone cautioning me about inrush current of drives and inverters when sizing these things. I bought D curve breakers sized for the rated current.

I kinda went to the opposite extreme and put separate line reactors, breakers & contactors for each drive. Been second guessing that decision every time I look at how crowded my cabinet is getting though.

[slodat]

I bought a single line side reactor, 45a input filter for the drive power and individual breakers for drive power. For drive logic power one breaker and individual input filters.

[RaptorMachine]

tagging along here.. went to automation direct.. looks like they have pretty good pricing..

but purchasing the line reactor.. 3 circuit breakers and 3 contactors ... theres 450.00 in my cart !!

have to do some thinking on this

[slodat]

I wouldn't do three contactors..

[martyscncgarage]

I am doing one Estop contactor....