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-   -   Kitchen table project started - Antek Power Supply problem (http://www.mechmate.com/forums/showthread.php?t=636)

KevinL Tue 19 February 2008 19:12

Kitchen table project started - Antek Power Supply problem
 
Hello Everyone,

I have been reading this forum for the past few months while gathering parts to construct a Mechmate. There is certainly a wealth of knowledge here. I have just started the "kitchen table" project, and I think I've already run into a problem with my power supply. It is an Antec PS-6N63R5R12 which should give me 63 VDC unregulated to drive the motors, as well as 5 VDC and 12 VDC for the PMDX and any accessories. When I plug it in, I measure 65 VDC (close enough) and nothing on the other two outputs. I then diconnected the wires from the toroid (a pair of brown goes to one regulator and a pair of orange goes to the other). I am a ME not a EE, but if I understand power supplies well enough, I should measure continuity on the orange pair and on the brown pair (they are just loops of wire within the toroid, right?). Instead, I measure continuity between one orange and one brown, and the other orange and other brown. I thought I could just switch some wire inputs to the regulators, but when I plug it in again and measure A/C voltage that would be going into the regulators, both brown/orange pair combinations measure 12VAC. Not wanting to blow anything up already, I haven't reconnected any wires. But if I were to reconnect the brown/orange pairs to the regulator inputs, wouldn't the DC output be somewhere around 8.5 VDC? I hope you can follow this. Thanks.

If I am understanding this correctly, I assume the wires within the toroid are perhaps all the same color, then the color coded wires are splice on later.

Richards Tue 19 February 2008 19:42

Kevin,
5VDC from 12VDC is frequently used. Dropping that much voltage across a regulator means that the regulator is going to get hotter than I would like, but it is common. As you pointed out, having 8.5VDC or so would be more customary. It looks like Antec might be using the same windings on several power supplies and just letting the regulator handle the final regulated voltage.

KevinL Tue 19 February 2008 20:00

Thanks Mike. So possibly all that is wrong with my PS is mis-spliced color coded wires? Would it make sense that 12 VAC would be regulated to 12VDC in one bank of the PS?

Gerald D Tue 19 February 2008 22:15

Kevin, I would hope that Antek have tested the power supply before despatch and that they have some warranty on it. So, I wouldn't mess with their wiring unless I really knew what was going on. Give them a call.

Richards Wed 20 February 2008 06:33

Kevin, Gerald is right. Call Antek first.

If you build your own power supply using toroidal transformers, you'll find that the 'order' of the wires is important. The first time that I used that type of transformer, I expected to use two 25-volt windings in parallel to get 25VAC, but I got 0-volts. What I found was that, because of the way that I had wired things, the windings nulled each other out. As soon as I changed two wires, everything worked. Since then I've been very careful to check how the transformer is wired before making any connections.

KevinL Fri 22 February 2008 20:19

Just a follow up. Mike was correct, they are dropping the voltage in the regulator. Even mentioned that it would get hot, but it is heatsinked. I reconnected the wires in brown/orange pairs and all is good.

Gerald D Fri 22 February 2008 21:10

Therefore, Antek didn't test the supply before despatch, which is worrying. Here we have builders who are too nervous to build their own power supplies in case they get some wires the wrong way around and the supply bursts into flames. So they let Antek take that risk - however Antek passes it straight back to you by making you switch it on for the first time. Charming! :mad:


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