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Managing obselesence with consultancy supplied PSU's?

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cupoftea

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Hi,
When you get a consultancy to design a 2kW offline SMPS for you, do you get them to do an identical “template” version of it aswell? The “template” version is exactly the same components, but layed out in “open format”, so that all nodes can be easily probed. Also, the “template” is layed out such that all components can be easily removed and replaced….eg, transformer pins are not soldered in…the transformer is tied in with say fishing line, and the coils simply get terminated to PTHs in the PCB, so that they can be easily removed. Also, all FETs and diodes have there own easily removable heatsink, so they can be removed and replaced easily.

Obviously, the “template” wont be any good for thermal testing, or EMC testing, but would be OK to say replace an obsolete component and check its basically OK at a first inspection.

Any daughter boards are not put in sideways on, but are horizontal, (parallel to the main board) so that components can be easily probed on them….also, the daughter boards are easily remove/replaceable, since they are on PCB platforms, to which they solder just like a surface mount component. (the platform is soldered in to PTH’s on the main board.)

This “template” PSU is needed because any of the components may go obsolete/long-term-nil-stocked, and the consultancy is not likely to be instantly available to manage the replacement of the obsolete components.

So do companies get such PSU “templates” made?
 

so you're asking the consultant to design a power converter, package it for use in some product,
AND asking them to re-package it, so that every node is available, and so that (at least the major power and control) components are available for replacement, to test if the replacement component(s) work ?

then you're going to store this gadget (somewhere safe) so that in 5 or 10 or 30 years when you need it, you can easily test alternative parts. (and hope it still works and hasn't been cannibalized)

an interesting thought - that will likely jack up the price significantly

i was involved in a project some years back where the customer came back to us after 30 years and wanted a few more of (whatever). it took a few days of digging through a lot of dusty old prints to find the drawings.
we built a few and installed them, then discovered that since the quality of the components increased significantly, the sensitive gate trigger on an SCR was now sensitive enough that it always triggered.

having the "open frame version" would not have helped, because the ones we built worked fine in the lab, but not in the field.

eventually we fixed it and it worked. but the time and effort wasn't worth it, because they only bought the 5 prototypes.

as for your situation, it may be more cost effective to have a few extra on hand to sell, or stock up on the components based on purchase history, and to pay attention to the last time buy notices, etc
 
" When you get a consultancy to design a 2kW offline SMPS for you, do you get them to do an identical “template” version of it as well? "

Presumably ask them to do the work and expect to pay the bill for the re-designed pcb's, assembly, run-up, testing and extra snubbing to get the thing to work properly in a more "open" format ....
--- Updated ---

" So do companies get such PSU “templates” made? "

Not usually - because the work is usually required to be fully documented which allows newer fets and diodes, Tx's etc, to be compared on paper - before being run in the product to see if efficiency and EMC are affected - in a factory situation you can usually measure AC power in to a few watts, often to 1 watt, on a 3kW converter - so if you see a change - it is real - ditto for EMC.
 
We will be doing an "open-format" 2kW offline SMPS which is a 2kW Dual Boost PFC, into a 2kW LLC Half Bridge.
It only has to give out 180V at 2kW.....no EMC pass or packaging etc required...so we will build it in a way that makes it easy to bring up......ie, in "open format". In fact, we only have small lab tables, and so we will have one PCB for the mains input filter, which wires to the dual boost PFC PCB, which in turn, gets wired to the 2kW LLC PCB.
Can you see any problems with such a wiring arrangement?

If it works, they will pay us £30k pro-rata each (two of us) to do the fully and properly packaged and EMC tested version. -At least up to the point where they think their own staff can take over, then our contracts will be ended.
 

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