How do I properly measure the current of power supply? February 01, 2015 12:37PM |
Registered: 9 years ago Posts: 189 |
Re: How do I properly measure the current of power supply? February 01, 2015 02:58PM |
Registered: 10 years ago Posts: 14,672 |
Re: How do I properly measure the current of power supply? February 01, 2015 05:53PM |
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Re: How do I properly measure the current of power supply? February 02, 2015 07:25AM |
Registered: 9 years ago Posts: 189 |
How do I identify two positive 12V rails?Quote
dc42
If the PSU has two separate 12V outputs, connecting them together is a bad idea. One of the outputs is likely to regulate to a slightly higher voltage than the other, and will end up taking nearly all the load. If you are using RAMPS, then I suggest you use one output to power the heated bed (the 11A circuit), and the other output to power everything else (the 5A circuit).
Re: How do I properly measure the current of power supply? February 02, 2015 07:41AM |
Registered: 10 years ago Posts: 14,672 |
Re: How do I properly measure the current of power supply? February 02, 2015 11:23AM |
Registered: 9 years ago Posts: 189 |
Quote
Another personal opinion: reusing an old AT or ATX PSU (instead of spending $30 to $45 for an inexpensive but new ATX PSU) is a most unwise decision - a lesson I have learned the hard way! ATX PSUs are dust magnets, sleeve-type fans (the most common type in old PSUs) become noisy and ultimately fail (and when they do so during a print, you'll definitely smell smoke coming out of the PSU), and electrolytic capacitors fail catastrophically (with smoke and a bang), sometimes killing whatever electronics you have connected to the PSU. Not only that, but ATX PSU circuits have very much improved in performance, reliability and efficiency in the last couple of years (2013-2014), so the few dollars saved when reusing old ATX PSUs in RepRap projects are just not worth the risks, hassle and time wasted.
Re: How do I properly measure the current of power supply? February 02, 2015 08:38PM |
Registered: 9 years ago Posts: 189 |
I had to agree with you. I did another load test on the ATX Bench power supply I converted two years ago. It has +3.3V@13A, +5V@15, +12V1@20A, [email protected], +5VSB@2A, power rating is 450W. When I connected 55W light bulb, it blew 2A of fuse. After replacing it 10A fuse, I connected 55W light bulb and the light bulb turned on. Out of curiosity as soon as I connected two 55W light bulbs, the PSU stopped running.Quote
dc42
2. The trouble with using auto bulbs as loads is that they take a very high surge current when you first turn them on. It may be this surge current that is tripping the PSU.
Re: How do I properly measure the current of power supply? February 03, 2015 05:13PM |
Registered: 9 years ago Posts: 189 |