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| Korad KA3005P power supply: UI changes |
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| 5U4GB:
--- Quote from: littleboot on February 28, 2024, 12:54:50 pm ---instead of a custom temperature fan controller, I bought a PWM fan controller on Aliexpress: Search for "12V PWM fan controller" --- End quote --- Hmm, for only a tiny bit more you can get something mainstream like the Arctic temperature-controlled fans, they use a FDB for quiet operation and come with a built-in temperature sensor on a short cable. For an 80mm fan you want the Arctic F8 TC. I used to have one of those somewhere but ditched a whole bunch of fans ("the fan club") during a clearout a year or two back, sigh. |
| 5U4GB:
--- Quote from: littleboot on February 28, 2024, 12:54:50 pm ---I forgot to add A additional capacitor on the 12V fan supply but, I have not checked the ripple.... just thought of it while typing this post :palm: (maybe I open it up again but seems to work perfectly so I think I will leave it like this) --- End quote --- That would be interesting to see and was actually my first thought, have you partially negated one of the main benefits of a linear supply by adding switching noise to parts of the circuit? |
| littleboot:
--- Quote from: 5U4GB on February 29, 2024, 11:48:31 am --- --- Quote from: littleboot on February 28, 2024, 12:54:50 pm ---I forgot to add A additional capacitor on the 12V fan supply but, I have not checked the ripple.... just thought of it while typing this post :palm: (maybe I open it up again but seems to work perfectly so I think I will leave it like this) --- End quote --- That would be interesting to see and was actually my first thought, have you partially negated one of the main benefits of a linear supply by adding switching noise to parts of the circuit? Hmm, for only a tiny bit more you can get something mainstream like the Arctic temperature-controlled fans, they use a FDB for quiet operation and come with a built-in temperature sensor on a short cable. For an 80mm fan you want the Arctic F8 TC. I used to have one of those somewhere but ditched a whole bunch of fans ("the fan club") during a clearout a year or two back, sigh. --- End quote --- Thank you for your reply I decided to open up the lab supply again. I wish I knew about the Arctic F8 TC sooner I would have probably used it, however I'm quite happy with the AliExpress fan controller because I can configure it. I'm glad I opened up the supply again and did a measurement, the supply noise is horrendous (did not expect it to be this bad :wtf:). When I'm finished with the measurements I will post measurement data before and after as well |
| littleboot:
Finished the measurements, as mentioned before the supply voltage is horrible, not only that it is actually load dependent ~20Vrms (light load, new fan standby speed) not 12Vrms. I don't like the over voltage for the fan, but if it dies it dies, problem for future me The fan controller AliExpress page is says it will operate from 8V to 18V. I looked up the LDO part number (78l05) on LCSC and it seems it can handle 35V max, assuming the 0603 capacitors 0.33uf and 0.1uF are 35V, 50V or higher I should be fine. I attached my full notes including measurement data as pdf. I measured the supply voltage with my scope in the following situations: - original fan; - original fan +200 uF (two SMD solidstate 25V 100uF capacitors https://www.lcsc.com/product-detail/Solid-Capacitors_AISHI-Aihua-Group-SVZ1EM101E06E00RAXXX_C320569.html) - fan controller without fan - fan controller without fan +200 uF - fan controller with fan (ID-COOLING NO-8010-PWM) - fan controller with fan (ID-COOLING NO-8010-PWM) + 200uF again another quick project that took way longer then expected |O :blah: |
| jewelie:
For reference the attached photos are of the Tenma 72-10480 I got from CPC Farnell late in 2022 ( https://cpc.farnell.com/tenma/72-10480/power-supply-1ch-30v-3a-adjustable/dp/IN06822 ) which is clearly a rebadged KA3003. I had a noisy fan issue that went away with a 25V 220uF electrolytic (poked deep into the connector, which is a bit hacky but it fits nice and tightly.) It's clear the fan doesn't cope that well with PWM. Oddly, with the capacitor, the fan runs faster at "full" loaded speed, which seems odd, unless the output isn't actually DC when at full speed? Excepting the risk of it falling out (which seems minimal, plus I can see it through the vents at the side) is it safe/okay to be using this 220uF cap like this? (If you'd like a laugh... whilst experimenting with the capacitor and fan I forgot to watch the 10R power resistor which I was only intending to misuse as a 90W heater for a few moments... I was only alerted by the magic smoke coming from the melting plastic box it was slowly sinking in to. :scared: Cue quick transfer to emergency containment pie dish. FFS! :-DD) EDIT: Oh I see. It's not actually a 12V peak fan control output then but actually higher? So "full" speed isn't DC then, that'll be why the original fan still gets improvement from the cap even at full speed. Does that mean I need a 35V cap rather than 25V for more safety margin? |
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