"Universal" input voltage -- 508A panel

Does anybody out there make panels or products that operate on 110/208/220/240?

I build fairly simple machines that use ADC DL06 PLCs with relay outputs. I control a number of relays, and often some solenoids, plus indicator lamps. I have a 24v power supply that supplies my touchscreen and indicators. I use 110 vac for relay coils and solenoids. My customer must specify 110 or 220 vac input; I add a 220 -> 110 control transformer if needed.

I'm considering changing all the relays and solenoids to 24 vdc coils. [I'm a little bit concerned about switching DC coils with my relay outputs -- worried about PLC relay contact life -- but that's a separate topic.] Since both the PLC and the 24 vdc power supply have 'universal' inputs (100-240 vac), I could, in theory, operate from any line voltage.

The challenge in doing this is in the input wiring of the machine. I need two input fuses for 220, but one and only one for 110 -- I can't have a fuse in the neutral! Also, in a 110 application, the neutral conductor should be white in the panel -- but if the machine were connected to 220, white would be inappropriate. I'm trying to sort out a rational approach that won't bust my UL 508A rating.

Anybody else ever toyed with this idea?

Paul in Wisconsin

What about using an export transformer?

Part of the idea is to ELIMINATE the step-down transformer that's now used in the 220 versions.

Paul

Sure would be nice to provide a one size fits all or crescent wrench or plug n play.

I dont think you can get there.

As I see it you have two choices
1. Trust your customer to correctly identify power receptacle in the wall for voltage. Then wire in the cord yourself. Use correct number of fuses and wire color.
2. Trust your customer to have the smarts on how to hook it up. The downside of this is your customer screwing up the hookup and then claiming it is your fault.

Dan Bentler

How about building the same panel all the time, and having an option of mounting a transformer and fused disconnect switch on the outside of the panel as an option?