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Wide input and output range power pre-regulator (85–265 Vac / 2.5–52.5Vdc / 5A)
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Sylvi:
Hi

For "safety" agencies, I thought 48V was their limit? The 52V output on this project might raise a flag on its own, but the other outputs are all very low and even were they added together they are less than 48V aren't they?

Is page-3 anywhere?
prasimix:

--- Quote from: Sylvi on March 12, 2019, 04:33:26 am ---Is page-3 anywhere?

--- End quote ---

Everything is on the GitHub repository (Eagle, png, PDF).
prasimix:
Thanks jbb for brought up a question about safety since I'd like to start certification procedure that address EMC and safety issues. My first intention is to get certification (at least CE) for this converter alone, and together with other modules that belongs to the EEZ DIB Bench Box 3 chassis.
I'm not sure anymore does applying for certification of the current design of converter alone makes sense. The main issue could be a lack of safety elements on its input, i.e. fuses, MOVs, TVS, "in-rush" current limiter, etc. I didn't incorporate them, since I'm not planned to use it alone, but in combination with AUX PS module that has all before mentioned parts.
I don't know how to interpret statements that can be found on the Mean Well site, for e.g. LRS-150-48 model, it seems that CE report could include statement such as:


--- Quote ---A component  power  supply  with  load  will  be  installed  into  final  equipment  which  consists  of  an  electronically  shielded  metal enclosure. Since EMC performance will be affected by the complete installation, the final equipment manufacturers must requalify EMC Directive on the complete installation again

--- End quote ---

Additionally, in its document EMI testing of component power supplies, the above cited statement can be also found, and also the following statement:


--- Quote ---... only products “intended for the end user” (such as external power supply - adaptor) should comply with the EMC directive. Component power supplies like our enclosed type open frame type SPS, which are intended for incorporation into an apparatus by professional system integrators and then be sold to the end users, are basically excluded from the EMC directive. However, in order to enable to customers’ end system to comply with the EMC Directive, MEAN WELL’s component SPS are still designed to meet the requirements of the EMC Directive.

--- End quote ---

What does it mean, that Mean well don't necessarily have above mentioned safety parts? Perhaps, the easiest way to find that out is to open one module. Anyway, your comments and expertise with certification procedure is welcomed.
jbb:
Well, I’m hardly an expert, but here’s what I do know:
- EMC certification usually applies to complete products. For something modulat/configurable, I think you give them a ‘maximum size’ test unit.
- it’s a good idea to do a ‘debug’ EMC pre-test of your converter module to verify it’s not spewing out all sorts of noise (radiated or conducted). This would typically be done with a fairly simole setup.
- ESD testing perhaps isn’t relevant for a module to go inside equipment.

I’ve never put a product through safety testing. It’s different and separate to EMC. I would recommend you put the CF DIC module through a ‘debug’ evaluation now - to identify any deficiencies - but don’t pay for the full evaluation and certificate until you’re confident you won’t change the design.

Your first challenge is to identify the appropriate standard. This should probably be done in conjunction with a test lab - they may offer some commentary on appropriate standards. You can probably also find a consultant to help you with it. Possibly you can talk to other open source hardware people in this area and make use of their experience.

After that I recommend buying the standard (unless it’s crazy expensive) so that you can assess all the requirements, e.g. creepage, clearance, required optoisolator requirements, how transformers are assessed etc.

You may also need some special things for compliance, such as high potential testing on every unit and detailed work (assembly) instructions to demonstrate that the product will be assembled consistently.

I don’t know how things work for kitsets. It could be ‘maker beware’ or it could be assessed in the usual manner (and it’s the maker’s problem if they don’t follow the instructions) or there could be special rules.
prasimix:
Yeah, the first choice possibly is kitset again as in a case of H24005 project, where CF-DIC will be one of the modules. But this time I'd like to engage in a certification that could in the long time create possibility to reach not necessarily just DIYers/hobbists group. Thanks for suggestion about ‘debug’ EMC pre-test procedure, I'll definitely ask certification house for such possibility.
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