Joined: 10/02/2006(UTC) Posts: 3,997
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This weekend I went ahead and built myself an interface between any PC power supply and my DC power bus for supplying DC power to building lights etc... Description and pictures are at http://layout.mixmox.com/1/5_Volt_power |
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Joined: 12/01/2002(UTC) Posts: 2,578 Location: Sweden
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PC power supplies may be a good source for powering equipment. Just one warning: PC supplies are usually grounded through the wall outlet, so you might get a common ground unexpectedly. Usually it is not a problem but in some situations it might be.
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Joined: 10/02/2006(UTC) Posts: 3,997
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Quote:[size=1" face="Verdana" id="quote]quote:Originally posted by perz <br />PC power supplies may be a good source for powering equipment. Just one warning: PC supplies are usually grounded through the wall outlet, so you might get a common ground unexpectedly. Usually it is not a problem but in some situations it might be.
Very interesting indeed. I just measured and I get a potential difference of 5 Volts between the case of the PC power supply and the 5V output and 12 Volts between the case and the 12V output, suggesting that the power supply case and the output ground are tied together. No surprise really. I also get continuity between the case and the ground lead in the power plug. So it means that the power supply ground is tied to the wall outlet ground as you say. My power supply that powers my layout is, I believe (will check) also grounded in the same way, in other words my layout common ground is also common with the wall socket so I think this means that all my grounds are common and I should not have a problem... Thanks |
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Joined: 19/10/2001(UTC) Posts: 2,379 Location: Lindome, Sweden
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Normally layout power is isolated from common, and should be. In the case of Mobile Station, Central Station, and some other new digital centrals it's important. In other cases it's not that important, provided you don't mix things up. /Lars
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Joined: 10/02/2006(UTC) Posts: 3,997
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Quote:[size=1" face="Verdana" id="quote]quote:Originally posted by Lars Westerlind <br />Normally layout power is isolated from common, and should be. In the case of Mobile Station, Central Station, and some other new digital centrals it's important. In other cases it's not that important, provided you don't mix things up. /Lars
In pre-CS systems suchas Intellibox and 6021 etc I think common grouns is the norm.... its good to point out though that this is for an INtellibox type system. |
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Joined: 12/11/2004(UTC) Posts: 548 Location: Maryland, USA
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Sorry for the basic question but could someone explain to me what common ground is and why it could be a problem?
always trying to learn here at Marklin Users University.
John
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Joined: 12/01/2002(UTC) Posts: 2,578 Location: Sweden
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Quote:[size=1" face="Verdana" id="quote]quote:Sorry for the basic question but could someone explain to me what common ground is and why it could be a problem?
"common ground" means that all the different power supplies in the system have one of their poles (usually the negative) connected together. If there is something in the system that forbids this you can have a problem. For example, the power supply into the MS can not have common ground with the track. If it has, you will burn the MS. In the normal case, "common ground" is good practice. But you have to know and avoid the exceptions.
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