Gyro Gearloose 0 Posted June 1, 2007 Any suggestions on suppression device that will correct this? I am having a problem with switching transients from an elevator tripping the DVR motion detector on all of my cameras not just the ones with lines running near anything related to the elevator. I have isolated the problem as coming in on the AC power to the DVR not through the camera coax. The transient is very fast and even effects a camera placed next to the DVR using a 3 foot cable and powered by a battery even when all the other coax is disconnected from the DVR. The DVR is three room away from the elevator room (about 20 feet). Will a standard UPS correct this? Share this post Link to post Share on other sites
zmxtech 0 Posted June 1, 2007 camera side> A crappy plug pack without proper regulation will cause the nasties to get thu A higher quality one\maybe even a switchmode. make sure it`s regulated not just rough DC. DVR side [AC power] > UPS for sure should fix it [there should be a UPS on the DVR\camera anyway] -the "smart" Bad guys always turn the power off !! Good quality filter may fix it -like the ones for HIFI It may be induced also. some ferrite clamp filters as a last resort my 2c[/b] Share this post Link to post Share on other sites
scorpion 0 Posted June 1, 2007 zmxtech hit it right on the nose! I agree! Share this post Link to post Share on other sites
Gyro Gearloose 0 Posted June 3, 2007 Thanks for the advice but the noise evidently isn't entering the system like I thought it was. It is evidently caused by spikes and noise generated when the elevator contactor engages to activate the motor when it is called to ascend ( Causing a huge sudden surge of current ) but it isn’t coming through the AC power to the DVR! In trying to figure out how the noise was getting into the DVR I completely isolated the entire thing by running the DVR, Monitor and one camera that was placed next to the DVR off of a UPS’s battery backup. I unplugged the UPS from the wall so there was no connection to anything in the building. The camera, coax and camera power supply are next to the DVR with only a 3 foot long cable. All of this stuff is 15 or 20 feet from the elevator and the elevator control room. I pushed the button to make the elevator go up and as soon as the elevator motor kicked in the DVR motion detector activated again. It has to be an electromagnetic noise field through the air. Possible solutions: • Buy 600 boxes of aluminum foil at the super market to wrap the elevator control room. • Turn down the sensitivity of the DVR motion detector. I chose the latter and the problem went away. If I had to suppress this spike and it is induced at this distance I wonder what I would have to do? I'm not sure where it's getting through. Share this post Link to post Share on other sites
survtech 0 Posted June 3, 2007 Are the camera video or power cables running parallel to elevator power cables? Most likely you are getting inductive coupling to either or both. Share this post Link to post Share on other sites
Gyro Gearloose 0 Posted June 3, 2007 Are the camera video or power cables running parallel to elevator power cables? Most likely you are getting inductive coupling to either or both. No, this test set up: the DVR, Camera, Power Supply and all the wiring are on a table in a room 15 feet or so from the elevator mechanical room. The power cables from the elevator to the electric room run down a 70 foot hall. The hall is about 15 feet from this equipment. I do have 13 coax and 6 UTP cables that run from the DVR room to this hall but the cameras have not been installed yet and they are not connected to the DVR. 2 of the unconnected coax parallel the power cables for about 60 feet down the hall. The other wiring parallels these power cables for 10 feet or less. These unpowered and unconnected coax and UTP's are in the DVR room about 3 feet from the DVR. Now that I think about it probably the spike is transmitted to the proximity of the DVR though these. Share this post Link to post Share on other sites
scorpion 0 Posted June 3, 2007 I am just stabbing in the dark. Is it possible to put some kind of filtering across the elevator motor? If you were to run the wiring in conduit, and if you put the DVR in a metal lock box and grounded the lock box would this eliminate the rf problem? How close is your wiring to the elevator's wiring? It seems that you have reinvented the spark gap wireless communication. Is it sending s-o-s? LOL. Share this post Link to post Share on other sites
VST_Man 1 Posted June 3, 2007 insulate everything connected to the elevator............camera also. Share this post Link to post Share on other sites
bigbuilding 0 Posted June 6, 2007 We have had alot of problems with cams we installed in elevators, it eventually turned out that the elevator contractor used the wrong type of cable. I have also read that the location the cams/power are grounded can cause interference. Share this post Link to post Share on other sites
