How to wire a 24VAC transformer to power multiple cameras

[tegatdavis 0]

I need to power 6 cameras each drawing 500 mA. In lieu of getting a central power supply, I'm considering using individual 24VAC transformers. I have one 24VAC plug-in transformer that's rated at 50VA. It says it can power multiple cameras but I'm not sure how to go about it or if it is even a good idea. You know just because you can do something doesn't mean that you should.

 

So is this a good idea? If so how would I wire it? Can I run all the camera power cables directly to the terminal on the transformer or will I have to do it another way?

 

The transformer I'm using is the Vitek VT-24VAC/50. Here are the specs:

# Lock on power outlet screw

# 24VAC Plug-in Transformer 50VA

# Terminal strip connection

# Capable of powering 3 to 4 24VAC cameras

# LED Power indicator

# UL Approved

 

Btw I'm a homeowner and this would be for my residence.

[squelch 0]

You can power multiple (8 with this model) cameras off one 24VAC transformer with these http://www.altronix.com/index.php?pid=2&model_num=PD8UL Using one for my home system, fits into any structured wire panel.

[Soundy 1]

I regularly power two cameras off a single 24VAC/40VA transformer... and I've seen up to four on a 40VA, although the transformer tends to run really hot. A 50VA should handle three cameras without even breaking a sweat. Some cameras will list their power requirements - a Panasonic WV-CP414 I have sitting here only draws 3.5W, so mathematically, I should be able to run 14 of them on a 50VA supply. I also have a National NLC-5700 that lists 3.6W on its label, and an NLC-5500 that lists 5.5W. So even at 10W per camera, your supply should handle 5 cameras without a problem.

 

At 500mA draw, those cameras would consume 12W (24V x .5A). That's pretty hefty - are these IR or PTZ cameras??

 

As for HOW to connect it, you can simply parallel the cameras to the transformer terminal. Some installations may require each line be fused, which you can do using a simple inline fuse holder available at any auto-parts or electronics-supply store:

[tegatdavis 0]

squelch,

That module looks exactly like the central power supplies from Altronix without the enclosure and whatever else they put in there. I'm curious though, once you have the module, what else would you need in there to make it work and how would you put it together? I've never done this sort of stuff before.

 

Soundy,

These are Nuvico day/night domes without the IR (CV-SD21N). Since the cameras draw .5A, would it make sense to get a fast-blow fuse rated at 1A or is that too low? I notice the fuses on the central power supplies are rated at 2.5 or 3.5 amps but those have to be large enough to cover most applications. Since this is customized for my setup, I figured I could go lower. As for surge protection, are the power strips with built-in surge protection any good or should I get individual surge suppressors?

[Soundy 1]

squelch,

That module looks exactly like the central power supplies from Altronix without the enclosure and whatever else they put in there. I'm curious though, once you have the module, what else would you need in there to make it work and how would you put it together? I've never done this sort of stuff before.

 

That's exactly what they are - you'd simply connect the transformer to the input terminals (the pair of screws in the bottom-right on that picture), and then each camera to its own pair of terminals as appropriate.

 

Soundy,

These are Nuvico day/night domes without the IR (CV-SD21N). Since the cameras draw .5A, would it make sense to get a fast-blow fuse rated at 1A or is that too low? I notice the fuses on the central power supplies are rated at 2.5 or 3.5 amps but those have to be large enough to cover most applications. Since this is customized for my setup, I figured I could go lower. As for surge protection, are the power strips with built-in surge protection any good or should I get individual surge suppressors?

 

1A is fine. The main purpose of the fuse is to protect your wiring - if, for example, the wires get shorted together, the fuse will blow before it either fries the transformer, or worse, starts a fire.

 

Powering the transformer off a single power bar with surge suppression should suffice. If you're in a problem area (inconsistent power, frequent lightning storms), make sure you get a good-quality one, and not some $5 special.

[squelch 0]

Correct, basically it's just the guts of the power supply minus the enclosure. You don't need anything else, wire your transformer and camera power wires to the Altronix PD8UL. Those Nuvico cameras are dual voltage so you won't have to worry about polarity using 24VAC. Here's the installation guide. http://www.altronix.com/p_pdf/PD8UL.pdf

[jeromephone 6]

anybody concerned about the UL rating? I think the box on the power supplies altronix is a big part of the UL sticker. Not an electrician just asking

[supra_06 0]

which is better, transformer type power supply or electronic types?

for individual power supply running on 220v then goes to a 12v dc transformers? i encounter interferences using electronic type of adaptors for power

[Soundy 1]

which is better, transformer type power supply or electronic types?

for individual power supply running on 220v then goes to a 12v dc transformers? i encounter interferences using electronic type of adaptors for power

 

I assume you mean "switching" type, vs. transformer? I've never noticed a performance difference of one over the other. Switching supplies are definitely far smaller and run a lot cooler for a given current rating, and are inherently a regulated output; the drawback is that they're traditionally more expensive, but that's becoming less and less the case.

[supra_06 0]

^

im not familiar with the terms..

we switch to using this smaller power adaptors that seems to be "electronic/IC types" for me.. and later after several months inferences occurs in videos, then replaced the power adaptors, and it greatly reduces the humming. so i suspect its about the electronic type transformers form china.

[jbooth1 0]

Don't forget to verify your wire guage. Running 18 guage to all six cameras pulling about 3 amps will decrease your voltage and heat the transformer. Hate to burn the house down. What will be the length of the cable runs.

[supra_06 0]

Don't forget to verify your wire guage. Running 18 guage to all six cameras pulling about 3 amps will decrease your voltage and heat the transformer. Hate to burn the house down. What will be the length of the cable runs.

 

^i dont worry about the voltage drops and ampere rating issues. i know it.

im an electrician. i just dont know it well when it comes to electronics.

 

whats the effect (if there is) of using electronic types or switching types on videos.

 

i am relating it in using vacuum tube type for my guitar amplifier is better in hum reduction instead of using IC types of guitar amps.

 

i need help.

 

 

*pardon for my grammar. im not an english

[Soundy 1]

Don't forget to verify your wire guage. Running 18 guage to all six cameras pulling about 3 amps will decrease your voltage and heat the transformer. Hate to burn the house down. What will be the length of the cable runs.

 

^i dont worry about the voltage drops and ampere rating issues. i know it.

im an electrician. i just dont know it well when it comes to electronics.

 

whats the effect (if there is) of using electronic types or switching types on videos.

 

Not a lot, really.

 

A "basic" transformer-type adapter uses a simple stepdown transformer (10:1 for 120VAC, 20:1 for 240VAC), a bridge rectifier, and a filter cap or two. If you figure the secondary of the transformer is giving you 12VAC RMS, that gives you just under 17VAC P-P (all these numbers are nominal, of course, assuming as solid 120 or 240 VAC RMS to the primary - real-world, the line voltage will usually vary by a few percentage points). Rectify that, filter the ripple a bit, and you end up with around 16-17VDC out.

 

As you know, you WILL get voltage drop over your camera run - how much will depend on the length of the run, the size of the wire, and the current draw of the load (camera, IR LEDs, heaters, etc.). With a non-regulated supply, you have a little more leeway, because it would take a hulluva long run of very thin wire to give you a 4-5V drop.

 

A typical regulated supply takes the output of that transformer, then, and regulates it to a very steady 12VDC (give or take a couple percent, depending on the tolerance of the components used).

 

Rather than reinvent the wheel here, I'll link you to a good article on switching supplies; how they work, and some of their benefits: http://en.wikipedia.org/wiki/Switched-mode_power_supply

 

The only real "problem" with switching and regulated supplies is that while they maintain a constant output voltage *at the supply*, the drop over a long run may cause enough voltage loss for the camera to simply stop working.

 

i am relating it in using vacuum tube type for my guitar amplifier is better in hum reduction instead of using IC types of guitar amps.

 

I'm not a guitarist, but as an audio engineer, I was always given to understand that the prference for tubes was that they produced a "smoother" sound than silicon, the reason being that when overdriven (ie. pushed to the point where the output signal is clipped), tubes generate "more musical" even-order harmonics (second, fourth, eighth, etc.), whereas transistors create odd-order harmonics that tend to sound harsher or "more mechanical". Of course, which is "better" is really a matter of preference; some guys like that harsher, shredded sound...

[supra_06 0]

nice to know.

 

i suspect this power adaptors from china causes the video disturbance, i replaced it with a transformer type and it worked good.

 

thats why im curious.

 

i think i need some seminars

[supra_06 0]

nice to know.

 

i suspect this power adaptors from china causes the video disturbance, i replaced it with a transformer type and it worked good.

 

thats why im curious.

 

i think i need some seminars