Author Topic: AC Power Relay IoT Dinglehopper: Design Advice  (Read 4878 times)

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Offline waymond91Topic starter

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AC Power Relay IoT Dinglehopper: Design Advice
« on: January 11, 2024, 01:40:28 am »
Hello!
For reasons out of my control, I have been tasked with design an IoT controllable AC power relay (with some surge protection built in).
This is my first PCB design that will have AC power coursing through its veins, so I was just hoping to solicit some general advice.

This thing is supposed to work on 120VAC with 10-12 Amps for max current draw.

I worry at this power level, the issue is no longer just with trace widths, but also with diaelectric of the board itself, and therefore the spaces between traces.
I also worry about KiCADs default thermal reliefs for the componens pads, as there is also quite a bit of power moving through these now.

Does anyone have some general guidance for this?

I also was working on a small protector circuit for the AC power.
My understanding is that we need to protect for over-voltage and over-current conditions.

To that effect, I have chosen some fuses, movs, and a thermal fuse to help protect the whole thing. Again, this is my first time spec'ing these components - so any tips are welcome.
I also am trying to use an off the shelf ac to dc converter, although I worry my approach here is also too simplistic.

I have attached the schematics so far, really just looking for feedback on the ac power components (not the esp32 or w5500).

I will also link in the parts pages for the components down below:
Main fuse: https://www.digikey.com/en/products/detail/littelfuse-inc/0215012-MXP/777451?s=N4IgTCBcDaIAxgIwFY6LAOgLIA0AKIAugL5A
AC to DC fuse: https://www.digikey.com/en/products/detail/bel-fuse-inc/RST-250-BULK/809314
MOV: https://www.digikey.com/en/products/detail/littelfuse-inc/V14E150P/1009240
Thermal Fuse: https://www.digikey.com/en/products/detail/bourns-inc/SA72SB0/6830067?s=N4IgTCBcDaIM4EMDsY4CMAMIC6BfIA
AC to DC Converter: https://www.digikey.com/en/products/detail/mean-well-usa-inc/IRM-02-5/7704628
Power Switching Relay: https://www.digikey.com/en/products/detail/cit-relay-and-switch/J114AF1CS3VDC-53/14002301?s=N4IgTCBcDaKP9-CBSBGZAWAggMWQYQMoDMAagCK4B0ArISALoC%2BQA
 

Offline liaifat85

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Re: AC Power Relay IoT Dinglehopper: Design Advice
« Reply #1 on: January 12, 2024, 02:58:42 pm »
At 120VAC and 10-12 Amps, you're correct in considering trace widths and spacing.  You can make a PCB  with FR-4 for a high dielectric strength to prevent breakdown at high voltages.
 


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