Don's Laser Things: K40-S DC Power Systems Design

Background

This post outlines the design for DC power in the K40-S

The K40-S BUILD INDEX with schematics

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General K40 DCPS design configurations

The LPS capacity:

+24VDC @1amp
+5VDC @ 1amp

Internally these are created from separate sections of the LPS so they have a total capacity of 29VA.
I do not know the power requirements for K40+smoothie when under full dynamic load and therefore
I am skeptical that 24VDC@1 amp can run everything in this box at full power.

I have not measured the dynamic load so at this point it is a suspicion. Power budgeting & verification is on my list of to-do's.

What configuration to use?

How you wire the DC power depends on what your expected full load will be.
Your full load includes DC current drawn from any/all of these:

Smoothie
Local Control panel (GLCD)
Steppers
Z table
Finder LED
DC pumps

DC Power Budget

Coming soon

Typical configurations

You can configure DC power to the Smoothie in three basic ways:

Way #1

+24VDC from the LPS
+5VDC from regulator installed on-board smoothie
Capacity: 24VA
Pro's: simple two wire connection
Potential Con's: marginal power for anything else, local display, finder led, Z table, pump etc.

Way #2

+24VDC from LPS
+5V from LPS
Capacity: 29VA
Pro's: more capacity 5VDC + 12VDC
Potential Con's: marginal power for anything else, local display, finder led, Z table, pump etc.

Way #3

+24VDC from external supply with selected capacity
+5VDC from regulator installed on-board smoothie
Capacity: based on external supply choice
Pro's: full DC capacity for K40 + expansion. Simple 2 wire DC wiring
Potential Con's: more complex wiring of AC mains (to add on supplies) and purchase cost of external supplies.

What works?

Many of the K40 conversions use Way#1 and 2, so it seems to work, I just do not know if it is marginal.

I chose Way#3 because:

I want as much isolation as possible from the HV laser supply. In my configuration only the grounds are common.
I wanted to make sure that the motors had full capacity under dynamic loads. I do not know the actual loads so I took the safe route :).
I wanted extra capacity for future accessories like the local GLCD and driving the stepper for the lift table.

BTW: I currently use the LPS 24VDC & 5VDC for other accessories such as external lift table and the finder LED.

You can employ Way#1 or 2 and then measure the PS voltage to insure that it is not drooping.