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Home > Archive > Electrical Engineering > August 2006 > Camera lv power supply's all on same phase ?
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Camera lv power supply's all on same phase ?
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| I have to install a bunch of camera in a large warehouse. Powered by 12V
power supplies, they are all going back to a dvr.
Someone told me that all the power supplies and dvr have to be on the same
phase.
Is he right ?
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| TimPerry 2006-08-28, 9:25 pm |
| Sonbo wrote:
> I have to install a bunch of camera in a large warehouse. Powered by
> 12V power supplies, they are all going back to a dvr.
>
> Someone told me that all the power supplies and dvr have to be on the
> same phase.
>
> Is he right ?
my recommendation: use what ever power source is convenient.
are these "wall wart" type supplies? are they grounded or do they just
have 2 pin?
is the video output balanced or unbalanced?
i would just go ahead and install the system and should issues arise add
buffers or isolators as needed. this will be MUCH less costly then bringing
in electricians to rewire a building.
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| **THE-RFI-EMI-GUY** 2006-08-29, 3:25 am |
| A concern but probably less important that they be on same phase of
electrical panel, you can have a situation where AC ripple, if out of
phase between the camera , monitor or DVR will cause the vertical to
roll. If this happens, reverse the AC side of the transformer/power
supply and all should be ok. For example: if you find that some cameras
roll and others do not, reverse the AC on the offending cameras.
Sonbo wrote:
>I have to install a bunch of camera in a large warehouse. Powered by 12V
>power supplies, they are all going back to a dvr.
>
>Someone told me that all the power supplies and dvr have to be on the same
>phase.
>
>Is he right ?
>
>
>
>
--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©
"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."
"Follow The Money" ;-P
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| Dale Farmer 2006-08-31, 9:25 pm |
| Sonbo wrote:
> I have to install a bunch of camera in a large warehouse. Powered by 12V
> power supplies, they are all going back to a dvr.
>
> Someone told me that all the power supplies and dvr have to be on the same
> phase.
>
> Is he right ?
>
>
Are these security cameras? If yes, don't worry about it. They
probbaly run on 12 volt DC, and this is a non-issue. You may have
ground loop issues on the signal lines, which are easily solved by
putting isolation transformers on the video signal lines.
For higher grade cameras, then your video contractor has people who
know exactly what they need, and which phase is not an issue. Power
quality and good grounding practices are.
--Dale
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