ProSoundWeb Community

Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Pro AV Forum => Topic started by: Dave Barker on April 17, 2011, 09:47:26 am

Title: Video and 3 Phase Power
Post by: Dave Barker on April 17, 2011, 09:47:26 am
I am working on a installed project that will have 108 video panels used to create a video wall.  We are looking to provide 100 amp 3 phase power to the wall.  The question has come up as to whether or not having the panels on different phase of service and being what 120 degrees out of phase would cause any problems when reproducing a single image on this large screen.  I am not a video guy or big power guy so I thought I would ask here.

Thanks
Title: Re: Video and 3 Phase Power
Post by: Greg_Cameron on April 18, 2011, 02:42:19 pm
I am working on a installed project that will have 108 video panels used to create a video wall.  We are looking to provide 100 amp 3 phase power to the wall.  The question has come up as to whether or not having the panels on different phase of service and being what 120 degrees out of phase would cause any problems when reproducing a single image on this large screen.  I am not a video guy or big power guy so I thought I would ask here.

Generally speaking, you want to balanced the load as much as possible across all phases on polyphase power systems. video & audio noise is a result of ground loops and not using different legs on a 3 phase system. In fact, loading down one phase and leaving the other unloaded will cause all the imbalance current to flow on the neutral line which can cause other issues.

Greg
Title: Re: Video and 3 Phase Power
Post by: Jonathan Kok on April 25, 2011, 08:32:32 pm
I am working on a installed project that will have 108 video panels used to create a video wall.  We are looking to provide 100 amp 3 phase power to the wall.  The question has come up as to whether or not having the panels on different phase of service and being what 120 degrees out of phase would cause any problems when reproducing a single image on this large screen.  I am not a video guy or big power guy so I thought I would ask here.

Thanks
That's actually a fantastic question...and I'm afraid I don't have an answer for you.  However, I would suggest that, with modern displays working at 120-240hz, I rather doubt you're going to notice them being out of sync (should that actually be a problem...which again, I don't know the answer to).  Basic math says that if in fact the TV's refresh rate is based on the source AC frequency, a 60hz TV at 180deg out of phase results in 1/120th of a second of lag between screens. 
Of course...I could be completely off base.
I'm more curious as to what source you're using to feed these...