Best Drive for Fanuc AC servos

I'd price the different options up.

How much are a pair of drives suitable for those motors?
How much would it cost if one of those motors died (the actual motor is unlikely, but the encoder might)?

How much is a set of new servos/drives?
How much would ou get selling the Fanuc system/motors?

Personally I'd replace with new, so I've got a known quantity, and know where to get spares, but then I'm looking at things from a commercial point, where if something breaks, I want to know what's needed and where to get it, to fix it ASAP.

My main aim is to keep the accuracy of the machine. I keep seeing posts that say the Fanuc set up is the best and its mad to replace with steppers.

I was also trying to keep the work load down and get it running Asap by just a rewire and not have to mess with pullies and belts.

Any idea on the value of a Fanuc OT system?

I know how much the Granite drives units are to run the Fanuc motors but there is such a variety of replacement servos and drives I have no idea what is the best option.

What nema 34 servo motors and drives would you recomend?

I can understand keeping things simple.

I have no idea about Fanuc values, but I know there are people who buy machines just to get the control, then scrap the machine.

Nema34 is 69.58 square distance between mounting holes, and 86 overall square.
Those servos are not actually that powerful. 112V and 1A puts them at 120W continuous (there will likely be an instantaneous rating 2-3x this).

Kinco from Zapp, you could go for SMH60 400W servos which are £264 along with a CD422 drive at £240 makes it £504 per axis (those prices are including VAT).
If you go for a Chinese option, 200W servo and drive combos can be had $264 per set (https://www.aliexpress.com/item/New-...760383887.html) or 400W for a similar price (https://www.aliexpress.com/store/pro...760376015.html with an 80 frame motor, or https://www.aliexpress.com/store/pro...760394727.html with 60 frame motor)

Or I've just remembered CNCdrive do servos and drives. They do AC servos in 156 and 400W versions at €156 and €198 respectively, although I can't find their corresponding drive in their web shop. They also do DC brushed servos, but I'd personally pay the extra for AC servos.

I had a dig around today and found the kolmorgen Goldline XT servo motors on another project and they are nema 34. If they work then they would get me started and maybe replace later.

That said Granite devices sell motors so If the Fanucs did pack up.

Are the ones from Ali express good quality?

I just had a search and the Goldline XT are shown as discontinued.

The Granite drives do look quite versatile, so using another motor shouldn't be too much of a problem.

DaveK used the Chinese drives on his Bridgeport conversion, and I'm pretty sure Jazz has used them.

I'm going to use Allen Bradley drives for my triac with fanuc reds
I've bought a few for around £100
I've been testing them with various motors up to 3kw off single phase and step/ direction. They are very versatile when you work out how to set them up!
I know fanuc use strange comutation but these can commutate without halls etc.
Probably the most versatile drives I've ever tested.

https://youtu.be/_N2Pkc51-t8