We have been experiencing this problem. 99% of it occurs in Asia. We have our device deployed in about equal numbers in Europe, Asia and Americas.
We have a Meanwell desktop GST series power supply feeding the unit. The Power supply output is 12V/11.5A (we do not need this much but the start inrush of a DC motor of the vacuum pump we use makes a lesser supply hiccup, hence the rating; otherwise the unit normally draws under 2A).
The 12V feeds two POLs, both are the same Artesyn 12V adjustable supplies, LDO03C-005W05-HJ (up to 13.8V Vin), producing 3.3V and 5V, not especially heavily loaded (3A-rated units).
The 12V input is protected by SMBJ13A (or now SMBJ15A, after we had the failures) transorbs (D3 and D8 in the attached circuit diagram). These are 600W-rated. At this point the manufacturer is Fairchild (On Semi).
In the attached sch you can see the input; pins 1,3 and 5 eventually connect to the same 12V, so effectively connected to the same Meanwell 12V output.
Recently we have been experiencing large scale failures (In Asia) of the Transorbs. Up 'till recently in has been almost exclusively D3, which I attributed to the higher rated fuse (F3), with the fuse remaining intact (the power supply goes to hiccups and does not burn the fuse). Upon changing D3 the boards would resume operation. The last couple of cases were different: it took out D8 and the F1 fuse. And, upon changing them, the board did not go back on line (I have not gotten the boards back yet to determine with 100% being sure the reason), which is indicative of the Artesyn POL(s) having been damaged.
This all is indicative of the bad power surges, but the unit has been tested in the certification lab for immunity, plus a third party tested the power supply with standard active load and the transorb using ECAT model E510A 1.2/50µs, 8/20µs combination waveform, 500A/1kV pulses (+/-90 degrees and such) and they could not fail the transorb. Now they are testing it with the only serious inductive load we have (a vac pump, 12V/1.6A motor) which is connected with the freewheeling diode across and which I looked at at some point and I failed to see any voltage surge across it. (the connection is shown in the second circuit attached).
I also have to add that the previous model used a much heavier power supply from TDK-Lambda (really overbuilt) and we never saw this kind of failures before, nor did we use any transorbs.
Has anyone experienced a similar problem, and if yes, was it with a particular power supply brand and in what part of the world?
Best
Mike.
We have a Meanwell desktop GST series power supply feeding the unit. The Power supply output is 12V/11.5A (we do not need this much but the start inrush of a DC motor of the vacuum pump we use makes a lesser supply hiccup, hence the rating; otherwise the unit normally draws under 2A).
The 12V feeds two POLs, both are the same Artesyn 12V adjustable supplies, LDO03C-005W05-HJ (up to 13.8V Vin), producing 3.3V and 5V, not especially heavily loaded (3A-rated units).
The 12V input is protected by SMBJ13A (or now SMBJ15A, after we had the failures) transorbs (D3 and D8 in the attached circuit diagram). These are 600W-rated. At this point the manufacturer is Fairchild (On Semi).
In the attached sch you can see the input; pins 1,3 and 5 eventually connect to the same 12V, so effectively connected to the same Meanwell 12V output.
Recently we have been experiencing large scale failures (In Asia) of the Transorbs. Up 'till recently in has been almost exclusively D3, which I attributed to the higher rated fuse (F3), with the fuse remaining intact (the power supply goes to hiccups and does not burn the fuse). Upon changing D3 the boards would resume operation. The last couple of cases were different: it took out D8 and the F1 fuse. And, upon changing them, the board did not go back on line (I have not gotten the boards back yet to determine with 100% being sure the reason), which is indicative of the Artesyn POL(s) having been damaged.
This all is indicative of the bad power surges, but the unit has been tested in the certification lab for immunity, plus a third party tested the power supply with standard active load and the transorb using ECAT model E510A 1.2/50µs, 8/20µs combination waveform, 500A/1kV pulses (+/-90 degrees and such) and they could not fail the transorb. Now they are testing it with the only serious inductive load we have (a vac pump, 12V/1.6A motor) which is connected with the freewheeling diode across and which I looked at at some point and I failed to see any voltage surge across it. (the connection is shown in the second circuit attached).
I also have to add that the previous model used a much heavier power supply from TDK-Lambda (really overbuilt) and we never saw this kind of failures before, nor did we use any transorbs.
Has anyone experienced a similar problem, and if yes, was it with a particular power supply brand and in what part of the world?
Best
Mike.
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