power supplies again - quick question please.

[volatileacid 0]

Guys.. just wondering if I could get a quick bit of guidance...

 

I've had three cameras fail on me, 2x JVC, and 1 Philips, (all 12v DC/24V AC cameras) after about 4 years use.

 

They were professionally installed, and running on a power supply that only gave out 18v AC!

 

Anyway, the cable runs are short - the PSU's are located within 4 metres odd of the cameras, and so I've got some new cameras, and this time round, I'm going to power them using 12 volts DC - because a) I think they'll last longer as there won't be the issue of voltage fluctuations that may occur with most of those 24v PSU's out there? (I may be wrong but please tell me if I am!)

 

Furthermore, I had banding on the output of one of the cameras before it died, and I wonder if it might have been due to distortions in the PSU (again, I may be wrong - the theories of a layman eh!)

 

I've done some research here, and other places, and I believe switching regulated PSU's are the best for the job when we're talking about powering precision equipment such as a CCTV camera using DC volatage.

 

I have the following PSU in mind - (good old ebay!) :

 

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=350158763911

 

I think it'll be up to the job, do you agree? I may buy a couple of them, and power each camera separately, even though, I'm sure @ 500ma per camera, I could use one PSU to power them both.

 

Cheers for any advice....

The below is a Pic of the old PSU I am replacing!

And below, is a Pic of its wire

[/b]

Edited February 13, 2009 by Guest

[VST_Man 1]

I would not do it this way..............it's not a power supply designed for a CCTV, it has no fuse, it's not 12VDC output, and only 1 amp. Not tomention that the install will look like crap.

 

there are some neat little power distro boxes available that you can connect a 2.1mm (common CCTV plug) or wire wire direct. It has 9 outputs that are PTC fused at 1amp. Then you can get a 12vdc PS and connect it.............

 

 

 

But, why all the work? Buy a 12VDC PTC fused Power Supply. You might save a dollar or two on ebay but the new PS is best.

 

also found this........... [/url]http://www.cctvone.com/products/spec.php?item=70507C

[griffonsystems 0]

buy a fused powersupply from altronix and be done with it unless you like making service calls

[survtech 0]

Given the choice, I would choose 24VAC over 12VDC any time. By the way, 18VAC is a bit low - are you certain the cameras have failed or is it possible the power voltage is just too low? That's 25% below spec, which is quite a bit. Typically, the range should be +/- 20% max (depending on the camera). For 24VAC, that's 19.2V to 28.8V.

 

Some 24VAC cameras can tolerate up to 30VAC or more, while some manufacturers insist on the supply being +/- 10%. Of course, then you have manufacturers like Dallmeier, who insist on the supply voltage being 12VDC +/- 5% which is both stupid and difficult to accomplish in real life installs. STUPID ENGINEERS!

[cachecreekcctv 0]

That little Power Supply is more for charging up Cell phones, etc. You need to find a proper power supply. You are better off finding a Power Supply (12vdc) out of an old PC and using that. Use at least a 250 watt (minimum) size. At least they are UL Listed. Just put them in an enclosure to protect the wiring, etc.

[survtech 0]

That little Power Supply is more for charging up Cell phones, etc. You need to find a proper power supply. You are better off finding a Power Supply (12vdc) out of an old PC and using that. Use at least a 250 watt (minimum) size. At least they are UL Listed. Just put them in an enclosure to protect the wiring, etc.

Beware of using PC power supplies. Many won't work properly or at all if they don't have a minimum load on either the +12VDC or the +5VDC output.

[volatileacid 0]

That little Power Supply is more for charging up Cell phones, etc. You need to find a proper power supply. You are better off finding a Power Supply (12vdc) out of an old PC and using that. Use at least a 250 watt (minimum) size. At least they are UL Listed. Just put them in an enclosure to protect the wiring, etc.

 

 

Here's a close up pic of the ebay adaptor I was! thinking of buying....

 

 

As you can see from the specs, it's outputting 12v @ 1.25 amps from this switched supply, it's not a cell phone charger that's for sure. As far as I'm concerned, it's capable of the task - what I need to consider, as others have said, is individual fusing, and chances of interference. If I had used this, I would definitely have got the fluke multimeter out to ensure it was outputting what it said it would.

Edited February 13, 2009 by Guest

[volatileacid 0]

By the way, 18VAC is a bit low - are you certain the cameras have failed or is it possible the power voltage is just too low? That's 25% below spec, which is quite a bit.

 

 

Yes, it was quite low - I have no idea what who ever fitted it, thought they were doing. I'm not sure why the cameras failed - but they were definitely dead. I took a couple apart !!!!!! they had a fuse inside!! I replaced one fuse - and it blew instantly on power up. So before chucking it away, I thought I'd stick some foil on the fuse - and smoke started coming out the back of the camera !!!

[survtech 0]

By the way, 18VAC is a bit low - are you certain the cameras have failed or is it possible the power voltage is just too low? That's 25% below spec, which is quite a bit.

 

 

Yes, it was quite low - I have no idea what who ever fitted it, thought they were doing. I'm not sure why the cameras failed - but they were definitely dead. I took a couple apart !!!!!! they had a fuse inside!! I replaced one fuse - and it blew instantly on power up. So before chucking it away, I thought I'd stick some foil on the fuse - and smoke started coming out the back of the camera !!!

Ah, the old "foil on the fuse trick"! An old quote says "If you use the wrong fuse, the circuit blows to protect the fuse".

 

Are you sure the pictures are of the same supply? The first one says Griffon and George and the output is 1A 9-0-9 VAC. The second says Creative and the output is 12V 1.25A.

[vin2install 0]

I thought I'd stick some foil on the fuse - and smoke started coming out the back of the camera !!!

 

LOL So now you have a broken camera too. Theres a reason for fuses.

[volatileacid 0]

Ah, the old "foil on the fuse trick"! An old quote says "If you use the wrong fuse, the circuit blows to protect the fuse".

 

LOL

 

Are you sure the pictures are of the same supply? The first one says Griffon and George and the output is 1A 9-0-9 VAC. The second says Creative and the output is 12V 1.25A.

 

Hey Survtech - the Griffon was the old PSU!!! It was the one supplying the 18v! The second pic of the three wires was from the same psu also. The multimeter was giving me a reading of 18 odd volts AC from the red and blue wires!

[cachecreekcctv 0]

Your Power Supply is really a transformer. AC voltage to AC voltage. Look at the symbol of the output voltage. The reason is reads " 9 -0 - 9 " is that one is neutral, and the other two are 9vac. You probably read 9 vac together on the other two leads, then 18 VAC betwen the two "hot" leads. I have many transformers like this. For other purposes, not CCTV. Look up "voltage symbols" or something like that. DC voltage has two lines, one solid, and one directly below that is "dashed". Yes, always be careful trying to substitute power supplies from one area or another. I build my own often, as I work with High Voltage equipment on a daily basis, and have since 1982 . I handle 480VAC on a daily basis, several times a day normally. If you lived closer, I would build you what you need, as my garage is full of electronic/electrical projects.

[survtech 0]

I handle 480VAC on a daily basis, several times a day normally.

Is this you?

 

[C7 in CA 0]

If you lived closer, I would build you what you need, as my garage is full of electronic/electrical projects.

 

You're lucky I don't live closer... Sounds like a place where I would want to hang out.

 

 

I handle 480VAC on a daily basis, several times a day normally.

Is this you?

 

 

LoL! hopefully that isn't cachecreek, but thanks for the "Flashback". I was installing an LB conduit fitting on the hot side of a 480v main switch and stuffed my 10in crescent wrench into a 277v buss bar. I'm still not sure if the big boom came from my short, or the fuse in the transformer on the road, but the ensuing fireball was quite impressive! unfortunately I burned the skin off of 4 fingers. The worst part was when my boss at the time ran up... He looked white as a ghost! I musta really scared the bejeebers out of him.

 

Have you ever seen forged steel welded to aluminum? Interesting to say the least...

[cachecreekcctv 0]

Not me. Never been hit by 480VAC 3-phase. Would not be the same afterwards, trust me. I would like to see the average Joe try his hand at High voltage 3-phase. Maybe I will post a photo , if this forum lets me, of a 2000 amp Fuse I change out once in awhile. I seriously doubt if anyone has been hit by installing too much Cat5E. I will have to remember that , the next time I am pulling 4/0 THWN/THHN. 18awg with 12vdc, please, give me a break.

[cachecreekcctv 0]

I also have two (2) 48" X 48" Stainless Steel Hoffman Enclosures , in my garage, that I am working on for big projects (not CCTV) . That should give you some idea of what might be in my garage. Power supplies.... I have dozens of 'em. Need a hydraulic Gate Opener? Got 2, built them both . Wire....tons of it. Plasma cutters, welders, whatever it takes.

[C7 in CA 0]

Not me. Never been hit by 480VAC 3-phase. Would not be the same afterwards, trust me. I would like to see the average Joe try his hand at High voltage 3-phase. Maybe I will post a photo , if this forum lets me, of a 2000 amp Fuse I change out once in awhile. I seriously doubt if anyone has been hit by installing too much Cat5E. I will have to remember that , the next time I am pulling 4/0 THWN/THHN. 18awg with 12vdc, please, give me a break.

 

Please do post the picture. I couldn't imagine anyone having a problem with that.

 

Other then the shock of the big boom I didn't even feel a tingle. I still have that old wrench...

 

I've never been hit by Ethernet, but T-1's come in on 22-24awg and it gets hot real fast if you lean against the punch block. Ring voltage on a POTS line will tingle pretty hard too, especially if your skin is wet.

 

I have a feeling you are insinuating something. I don't know why; I am sure close calls like that happen everyday.

[vin2install 0]

I handle 480VAC on a daily basis, several times a day normally.

Is this you?

 

 

LOL "FLAME ON!!"

[cachecreekcctv 0]

By " if this Forum lets me", I meant that I, for the most part, cannot upload photos, as I have tried several times. I keep getting some sort of "file upload error". I upload photos to other sites I belong to, but can't here, most of the time. I have tried to reduce the size of my photos to the smallest I can, but still no luck. Not "insinuating" anything really. Everyone has his/her own "specialty", and I was just trying to offer someone advice on their power supply, nothing more. One big reason I have never offered my help in the "IP Camera/Transmission" column, here on the forum. I definitely wouldn't be of much help at all.

[C7 in CA 0]

Sorry to hear about your upload issues. These message boards are one of my favorite Internet resources, but sure can be quirky sometimes.

 

Have you thought about using a photo sharing service and just embed the photos in your posts? I use http://photobucket.com --mostly because they were one of the first and that is how long I have been using them. The accounts are free and it's a good place to store copies of the pictures anyway.