24V power supply(s)

[spillage]

The AXBB-E basic wiring diagram shows a single 24V power supply for all of the main and ancillary items.
Can multiple 24V power supplies be use?... say 1 for the drivers, 1 for the VFD, 1 for the limits and e-stop, etc.

What items would you use a common supply for?

The main reason I ask is, the servo brake I’m looking at recommends using a separate power supply... I take it this is because of back EMI concerns... though I would think a diode and a ferrite core at the brake connector should eliminate this.

Thoughts?

[Robertspark]

it depends how you have stuff wired up .....

normally voltages are measured with respect to something..... from one wire to another, and then measured with respect to each other.

if they share a common point (-) then the voltages will be with respect to each other.

my CNC control cabinet has 5x power supplies .... possibly 6.... (I forget).

some are isolated (they share no common connections)

and at least 3 are with respect to each other
a separate 5v, 12v and 24v sharing a common zero volt (-) rail. note it is NOT ground, as it is not shared with electrical earth or ground.

you mentioned 24v for the drives.... to do what?
the step and dir signals are (usually) 5v, and the power supply to the drives is usually much higher. 40v, 50v +
the power supply to the drives is not normally shared with anything and does not even share s common zero volt/ (-) line except maybe with other drives.....
I have 5x drives on 1 50v AC power supply and 2x drives on another 40(?) v AC power supply.
the power supplies have multiple windings (2/power supply) and even those are not shared except by a few drives)

the vfd sometimes proves their own 0-10v or 0-24v supply..... it just depends....

the best thing is to draw out how you want to wire it all and if you are not sure post your sketch + product names and model numbers for people to comment on and offer you advice.

I have 3x cheap PoE (48vdc) power supplies I use for testing which are wired in series of(-//+>>-//+>>-//+) and could be lethal being DC. but I know what I'm doing and when I need to use them for testing. I also have 2x home built 0-30v adjustable 5A power supplies that can provide 0-60v at 5a for testing too if wired in series or dual 0-30v if sharing a common zero volt (-) or -30v to +30v if using the shared center connection as zero volt....

once you let the smoke out of the devices there is no way to get it back into the devices....

[spillage]

Robert,
I was going by the “example connections” drawing on the AXBB-E page of the UCCNC website... I guess I glanced too quickly and took the colors as being the same... the drivers are a separate (not 24V) supply.

Anyway, I am just trying to determine if I could or should use separate 24V supplies for e-stop/limits, coolant/air solenoids, servo brake, etc... primarily to help eliminate interference potential.

[spillage]

Ok, so this is my ps game plan.

5v3a for the axbb-e (should cover max draw potential).
24v5a feeding the axbb-e (should cover all outputs to their max draw if I expand).
24v3a for the Z axis servo brake (1a continuous draw).
24v10a for ancillary items (spindle cooling pump & fans, case cooling, mist coolant solenoids, etc).
72v20a for the servo drives.

With emi filters on the mains supply, vfd, and the servo drives ps, and the fact the vfd and servo drives ps are going to be in a separate enclosure from the rest of the stuff, I’m hoping for relatively clean power.
All external power and signal cables will be shielded... any bemf potential source will have a diode and ferrite core for good measure.

[Robertspark]

the only back emf sources are your stepper motors and it occurs under deceleration.

don't put anything on your secondary side of your drives as back emf is just a function of the motors working.

a better power supply may solve my your back emo issues such as a toroidal transformer.

some of those power supplies can be merged and just iluse one and probably don't need to be that highly current rated.... just my opinion ymmv

[spillage]

I plan on using servo drives.

EMI filters on the mains input to vfd and toroidal ps, and one on the mains entering the cabinet.

What combinations/reductions would you recommend?