EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: Chris Wilson on October 16, 2015, 10:35:21 pm
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Self build or commercial, what are my options? Currently struggling with a toroidal transformer and a full wave bridge, unregulated. Voltage drops to circa 65 / 70V DC under load. Would prefer to steer away from a SMPS, especially self built, too complex. Thanks. Mains available here is 230V AC, 50Hz, about 60 Amps
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if it drops to 65V under load your transformer AC output voltage is too low for 100VDC.
The problem with regulation at this current and voltage difference is you either have a massive heatsink or go switchmode. Your looking at 40-50V difference between noload and fullload DC output which is 50V*10A = 500W
There are a few more specialized options, such as a servo controlled variac with feedback from the DC output after the bridge. But this is obviously slow to respond so is only useful in limited situations.
Best option is to just look for something on ebay. Or perhaps multiple units that can be wired in series to give you 100V. (Since 100V isnt going to be very common for a single unit) Two 48V 10A units might be easier to find and could be tweaked to output 50V easy enough with some understanding of how switchmode psu feedback works.
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I'm not saying you should get this, i cant figure out if its compatible with being wired in series but.. Two these might work and would be under US$100
http://www.aliexpress.com/item/led-power-supply-switch-600W-48v-12-5A-ac-dc-converter-Input-220V-S-600w-48v/2026109253.html?ws_ab_test=searchweb201556_7,searchweb201527_2_71_72_73_74_75,searchweb201560_4 (http://www.aliexpress.com/item/led-power-supply-switch-600W-48v-12-5A-ac-dc-converter-Input-220V-S-600w-48v/2026109253.html?ws_ab_test=searchweb201556_7,searchweb201527_2_71_72_73_74_75,searchweb201560_4)
I'm pretty sure this will have a pot to make tweaking the output to 50V dead simple.
Cheaper one
http://www.aliexpress.com/item/New-model-48V-10A-480W-Switching-Power-Supply-Driver-for-LED-Strip-AC-100-240V-Input/32345061556.html?ws_ab_test=searchweb201556_7,searchweb201527_2_71_72_73_74_75,searchweb201560_4 (http://www.aliexpress.com/item/New-model-48V-10A-480W-Switching-Power-Supply-Driver-for-LED-Strip-AC-100-240V-Input/32345061556.html?ws_ab_test=searchweb201556_7,searchweb201527_2_71_72_73_74_75,searchweb201560_4)
Of course this is relatively cheap china stuff, so quality is a bit unpredictable.
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No real help to you, I'm just curious. Is that a residential branch that you modified that has 230VAC @60A,13.8kVA?
No here in the UK we are terribly good at taking a source of heat, wastefully turning it into electricity by burning it miles away and loosing 60+% of it's heating power, then channaling it all the way to our homes so that we can use electricity to..... make heat :palm:
Many houses still have electric cookers and heating, these may be deemed to be safer for elderly people etc but many of us are now on gas.