8x4 Build based on plans by Joescnc Hybrid R&P

[JAZZCNC]

Sorry if it seems like i'm doing it all wrong but I'm loving my build so far as it's starting to take some shape :)

Your loving it now but you won't be if you keep ignoring advise cutting corners trying to save a few extra pounds. It's very easy to spoil a machine when just few £100 more would make a great machine and unfortunatly you only realise this after the money is spent.!

I won't give Bum advise so I'm not giving you a "just good enough" solution but will give you solution that is what's required for good machine.

Because your using R&P which is only 50-60% efficient compared to ball screws which are 90-95% couple this with linear rail system that's is even less efficient then you'll need extra power to deal with lower efficiency. Also because you'll be using ratio 3:1 then you'll want motors which spin little faster but still have torque higher up the RPM range and 50V drives with 48Vdc won't provide enough power. (Also 48V is too close to the Drives 50Vdc max so you risk blowing drives up)

Ideally, with R&P setup, esp one that isn't very efficient then you'd run Nema 34 motors with Mains voltage or higher Dc voltages around 100Vdc.
So if you must use Nema 23 motors then you want to be running them around 70Vdc with 80Vdc drives.
Also you want Unregulated PSU not Regulated Switch mode supply. Reason for this is that under de-acceleration the motors become dynamo's and dump the power back to the drives which then dump this back to the PSU (Back EMF) and if the PSU as protections built into it then will shut down which is bad news.
On Small slower machine with light gantrys then can sometimes get away with this but on large machines with heavy gantry traveling at higher feeds whcih routers tend to do then it will become a problem.
The PSU you want is Unregulated toroidal PSU which use capacitors that store energy and absorb any Back EMF. These are actually very easy to make and will work out cheaper than buying a large PSU, it also means you can tailor Voltage and Amps to your exact needs.

So the setup I suggest with nema 23 motors is this.
4Nm motors
80Vdc Digital drives running motors at 68-70Vdc.
Toroidal PSU transformer spec'd to output 68-70Vdc

With Nema 34 Motors:
4.5Nm Nema34
80Vac (100Vdc) Drives
Toroidal PSU transformer spec'd to output required.

Stay away from kits they are always compromised in some way.