Mod Meanwell SE-450-36 for Duet3
bearer last edited by bearer
There has been a few threads on running the Duet3 at increased voltages, and I also wanted to go up from the 24V as well, but stay within specs.
Looking at the voltage range for the low cost Meanwell SE-450 supplies were 21.6 to 28.5V and 32.4 to 39.6V. I decided to buy the 36V and tweak the feedback a little to drop the voltage down (instead of trying to increasing the 24V as it would increase the power beyond the rating while the 36V would supply less power at max current, possibly slightly lower efficiency if anything)
Anwyays, the feedback potentiometer is 1k, with the voltage being 32.4v at 1k. Going past 1k3 had no further effect on the output which was 26.5V at that time. So I cut the trace, soldered on a 350R 0603 effectively in series with the 1k pot bringing the range to 26.5 to 32.5V.
(another option would be a 10k pot with a 1k5 resistor in parallel, but didn't have any that fit)
Forgot to take a picture after, but the partial reverse engineering is shown (top side image is mirrored).
Might be overkill for 0.4v out of spec, but ... use the information at your own risk! (and do be careful to discharge the high voltage capacitors if you go poking inside the supply, those things can shock you even after unplugging the mains)
Oh, and caveat emptor - the Meanwell SE series has a 2 pin connector (not tested with mod), however it is a remote sense input, not a on/off input, and they do not have any active power factor correction. (Sloppy research on my part..)
edit: https://forum.duet3d.com/post/146034 suggest RS-350-36 can be turned down to 30.9V without modifications.
Thanks for sharing!
Have you traced the circuitry that the two traces from the pot go to? There may be another resistor up there whose value could have been changed instead.
bearer last edited by
Have you traced the circuitry
Only half heartedly as it looked to go straight to a dip chip under the transformer, but i'd be surprised if there wasn't another resistor there somewhere.