Class 2 SMPS - Removing the Y capacitor - Good design solution wanted !

[Ian.M]

I see a 'Y' capacitor! C006 (top left) links FG (which we can assume is incoming PE Ground) to the negative side of the primary DC bus, and the chassis ground symbol links FG to the output ground.

[Kleinstein]

I see a 'Y' capacitor! C006 (top left) links FG (which we can assume is incoming PE Ground) to the negative side of the primary DC bus, and the chassis ground symbol links FG to the output ground.

It is supposed to be Y class capacitor - but in the BOM it is only listed as 400 V type, though the specific type may be OK

[BrianHG]

High quality USB-PD wall warts without Y caps, double shielded transformer core and extra wide gap isolated transformer secondary windings exist, even without even a GND pin and they have full approvals.  But if you want the full 60 watts, you need an PD negotiating IC to receive the 20v, otherwise you are stuck with 5v, 2amp.  On the up side, if you gone through the trouble, now your device is also compatible with USBPD power packs.

[Nominal Animal]

Can this be used as reference to modify Meanwell PSU? Like the RPS-300 27v or LRS-350 48V?

Mean Well already manufacturers many class II isolated power supplies, for example the HDR series DIN rail ones (HDR-15 to HDR-150), IRM encapsulated board ones IRM-01 to IRM-90), and others.

(RPS-300 is class I isolated, but medical safety approved, i.e. with less than 150µA leakage current.  Open the Mean Well AC/DC Product List, and examine the model-specific PDF files on the right-hand side, to check for isolation class, EMI, and safety specs.)

For high power class II isolated medical safety approved supplies, I'd look at RPS-400 and RPS-500 series.

[coppercone2]

if the earth is  ground reference, its surprising you can pick up a shock, unless the impedance of the earth wire is too high.

in a sense you are dealing with crappy infrastructure in your home/buisness no?

I wonder what happens to these devices if you get closer to the g rounding rod/panel and also start lowering impedance with straps to make a RF ground

[smile]

Thanks for all replies.

So this IRM-45-24ST will not leak 80-50V AC on the negative output pin if ungrounded right?
This will be fine then for automation controler.

"in a sense you are dealing with crappy infrastructure in your home/buisness no?"

yes. no proper grounding.

What about main power for servo/stepper motors. I have Meanwell RSP-320-48 6.7A that can't use also.
What to replace it with?

Regarding "medical" gade nonsense with micro amps leakage see this video for RPS 200 I made years ago
https://youtu.be/lea5JhNpddI

Do you really think the neon lamp would light that bright on 150µA leakage current? For the amount of overpiced money they cost, they should leak none.

[smile]

Leakage current for HDR-60-24 is not specified in data sheet?

[smile]

Paper on Y cap leakage current
http://www.epqu.agh.edu.pl/archives/journal/v15i2/Jha%5B2%5D.pdf

Seems I can remove it since I do not care about EMI nonsense anyway.

[coppercone2]

its a bad idea you would be surprised how many things can be effected by bad electronics.

[smile]

Well I decided to put a transformer 24v
https://www.tme.eu/lt/details/tmbz63_002m/transformatoriai-su-tvirtini-elementais/indel/tmbz-63-002m-65va/

then this converter to 24v
https://www.aliexpress.com/item/1005004463519267.html

For other more powerful PSU that drives motors these should be no issues as no direct contact betweek GND and ground.

[coppercone2]

if you did a modification, you could experiment with putting different Y caps across the chassis from the new power converter, something might be better then nothing.