Question and Caution On MG Electronics Power Supply

[Gyro Gearloose 0]

Question and Caution On MG Electronics Power Supply

 

Question: If auto iris lens are not provided adequate current and their motors are just left clicking with no picture, will this condition likely hasten lens burn out?

 

We recently purchased an MG Electronics DPS-12C-16UL power supply. It is 12V, 16 cameras, rated at "8 amps supply current" with PTCs and LEDs for each channel.

Lets see ... 16 cams divided by 8 amps is .. um .. er .. 500ma per camera.

However when you check out the sticker on the inside of the door it claims that each channel has only 250ma available.

 

Since our cameras typically draw less than this we connected them. We found however that the channel LED started to wink for one of the cameras and we had no picture.

At the camera we found that the auto iris motor was clicking even though the voltage was adequate. We found that the current for the other cameras were 194ma to 203 ma and steady. The current for the camera that wouldn't work was jumping all over the place.

We connected this camera to a different brand of power supply & it started to work. We found that the voltage was the same as with the MG PS but the current was stable at 218ma, well below the MG PS claimed limit of 250ma.

 

Conclusion: This PS can't even provide the reduced claim of 250ma let alone the advertised claim of 500ma.

 

Most disturbingly when I turned the power supply off for a few seconds & then back on to simulate a temporary power outage seven of the nine cameras, the ones with the highest current, refused to come back up with a picture. At each of the effected cameras we found the auto iris motors clicking. They had voltage but fluctuating current.

 

Is it likely that if there was a temporary power outage and subsequent restore that caused the cameras lenses to receive inadequate current for a long period of time such as when a system is unmonitored for days or weeks will the camera lenses prematurely burn out?

[CollinR 0]

Did you try to exchange the PS? I have installed many of these and never a trouble. Granted most of my cameras are in the ~200ma range.

[CCTV_Suppliers 0]

Here is a food for thought... How many electrical outlets do you have on the same power line stretch? What other gadgets do you have sharing the same power, like TVs, fridge, lights, etc...

 

Here is where I am going with this. What you are describing could be interpreted in two folds...

 

First: You many not have enough electrical power available for your power supply. Not knowing exactly which cameras you are using, but serving 16 cameras from this power supply and NOT HAVING ENOUGH power available will simulate the same problems that you are describing.

 

Second: Pick up an extension cord and connect it to a different power source and see what happens... Chances are very good that by changing the power source could solve this issue.

 

As for power fluctuation causing your lenses or the cameras to be damaged, that is a very remote possibility. Basically, if your cameras and the lenses do not get enough power, they will not fail, rather they will not work right...

 

I am not sure if you can do what is called a "load test" to determine how much power you actually have left from your circuit breaker and then calculate how much power will you need for your system by looking at the specs of the cameras, the lenses and even the DVR/monitor combination. With some simple calculations you can determine if you can use the same power line or you need a different power line from a difference circuit breaker or better yet, may be a separate circuit breaker for your system only...

 

At the worst case scenario, you can change the power supply only if you performed the above tasks and confirmed that you have more than adequate power available.

 

I just looked at MG Electronics Power Supply website... and dependent which power supply you bought and more importantly, what is your power consumption based on your number of cameras, the DVR and monitor, you may be trying to pull more from the power supply that it does not have available from the outlet that it may be plugged into...

 

At least this is my 2 cents of the day...

[CollinR 0]

As for power fluctuation causing your lenses or the cameras to be damaged, that is a very remote possibility. Basically, if your cameras and the lenses do not get enough power, they will not fail, rather they will not work right...

 

The click sound is interesting to me, I have only observed that on auto backfocus cams and DC lenses on a cam set to video drive.

[survtech 0]

Most likely, the cause of your problem is not the continuous current draw that each camera pulls, but the instantaneous peak current during startup. That said, it is not good practice to draw more than 75% of the rated power from a power supply. In fact, I normally do not recommend exceeding 50% to 60% of rating to allow for surges and varying loads.

[Gyro Gearloose 0]

Most likely, the cause of your problem is not the continuous current draw that each camera pulls, but the instantaneous peak current during startup. That said, it is not good practice to draw more than 75% of the rated power from a power supply. In fact, I normally do not recommend exceeding 50% to 60% of rating to allow for surges and varying loads.

 

High inrush current, an interesting idea. Unfortunately I don't have equipment to measure this. I only have a multimeter not a scope.

 

These are Nuvico domes CV-S266N and CV-S3895N. The manufacturer rates each at 500ma but they actually measure about 200ma.

 

Curious, Nuvico techs will not vary from the 500ma rating but they concede that the cameras actually measures around 200ma. Maybe the rating is based on issues like inrush current. I don't know.

 

I'd ask Nuvico but their US Techs sort of present a language barrier. Additionally I'm not impressed with their depth of product knowledge.

 

I think Survtech's advice about the sizing of the PS is probably a good one, but if used consistently it sure would add to the cost. However, it certainly would be cheaper than going through this. It would be interesting to compare some other PS to see how they fare.

 

I suppose I could apply a 230ma load, like a resistor, with no inrush current & see what happens.

 

Would it be to much to ask that the manufacturers include a comprehensive set of specifications instead of these vague, weasel worded ones that that only serve their sales departments short term goals? I know in the past I've seen power supply ratings for other applications that include specs for continuous and surge current.

[RickA 0]

Do you have the heater/fan add on with those domes? The spec sheet calls for an extra 20voltamps with that addition, which would put the range above 1amp per camera.

[CCTV_Suppliers 0]

Most likely, the cause of your problem is not the continuous current draw that each camera pulls, but the instantaneous peak current during startup. That said, it is not good practice to draw more than 75% of the rated power from a power supply. In fact, I normally do not recommend exceeding 50% to 60% of rating to allow for surges and varying loads.

 

In-rush current or instantaneous peak current is not an issue.. Most of the power supplies already have all the necessary filters to minimize this effect so that it does not cause problems with hardware that it will serve.

 

The same applies to laser printers or even copy machines that pull tremendous amount of power at their startup and specially when they are printing. Try several of these type of gadget to turn on at the same time while you have several computers going and see what happens to your circuit breaker..

 

I still think the problem is that the Power supply is not provided with enough power, thus does not have enough current available for 12V supply. We had several instances where customers installed the system and then started having problems almost instantly... All they had to do was to change the source of the power...

[CCTV_Suppliers 0]

Here is another option that you can look at...

 

Since I am not familiar with MG Electronics Power Supplies, the question is if these power supplies are "adjustable" for the voltage.. I know that Altronix DC power supplies are.

 

If so, then you can measure the voltage supply at the camera end to see if it is 12VDC and if not, increase the voltage accordingly.

 

Take a look at your power supply and see if you have any adjustment pots that could give you this option...

 

Good luck!

[Lolo Wolf 0]

In your original post you stated:"We connected this camera to a different brand of power supply & it started to work" When you swapped the PS was it local: single isolated transformer, near the cam or on the original power wire run? Aside from the current draw and related issues discussed perhaps you should check your power runs (lengths/voltage drop)

[Gyro Gearloose 0]

Did you try to exchange the PS? I have installed many of these and never a trouble. Granted most of my cameras are in the ~200ma range.

 

Glad to hear that someone else has successfully used this PS. I'm really surprised it doesn't cut it since as you can see my cameras are around 200ma also.

 

I do have a question for you.

Have you ever measured the actual current of your cameras? The cameras actual draw can be much different than the manuf. spec., as I found out.

 

If it is drawing 200ma or more it would be interesting to know what happens if you drop power for 10 seconds and restore it. (You can't turn it off for to long because when it cools down a bit it restores most of the cameras except for the ones at 220ma or above.) As I mentioned I'm concerned about burning out a lens servo motor that is only partially functioning.

 

The distributor will take the PS back and I was ready to do this until you indicated that you used them with no problem. The question is do I want to take a chance with another one of the same make & model?

 

I called the manufacturer and finally got a hold of someone that said that this PS was of an older design. Because the cameras features continue to expand each year, an example is OSD (On Screen Display), camera current draw is greater now than when this PS was first envisioned. They have had other similar recent complaints about this particular model.

 

When I asked him why they didn't publish honest specifications he said he has sent that recommendation up the line several times. Their other staff members said all this is the fault of the Chinese that actually manufacture it.

 

So I've decided not to change it at all I'm just going to tell my customer. "It's Not My Fault It's The Chinese." and give them a phone number in Hong Kong.

 

They can put their complaint in line with the poisonous tooth paste and the dangerous toys that could maim and kill American kids.

Edited December 2, 2007 by Guest

[Lolo Wolf 0]

Gyro, there is still some high quality American gear being made... I try to buy American when I can (american labor needs to put food on their table too, our goverment seems to have forgotten that...unfair, oneway trade agreements...etc)....here is a good source for quality PS http://www.bearpwr.com/

[survtech 0]

Gyro, there is still some high quality American gear being made... I try to buy American when I can (american labor needs to put food on their table too, our goverment seems to have forgotten that...unfair, oneway trade agreements...etc)....here is a good source for quality PS http://www.bearpwr.com/

None of their products are really suitable for CCTV. They don't offer screw terminal connections or easy multi-camera capability.

 

Try Altronix. Most of their products are also made in the U.S.; they offer models in many different configurations:

1. 24VAC - 1 to 32 outputs
   12VDC - 1 to 32 outputs
   6-15VDC (adjustable) - 4 to 16 outputs
   Rack or wall mountable

 

They are available for indoor or outdoor; with fuses, circuit breakers or ptc (automatically reset after a short is removed) protection.

[Lolo Wolf 0]

"None of their products are really suitable for CCTV" Not true many of there ps have terminal connects as well multi configs highly suitable for standard/custom cctv work, (the inrush current limiting and emi filtering specs are no hype) high quality.... Ive used both their PCB mountable products as well the chassis mounted products for custom enclosure work and entry work and lately have found some of the Altronix prods purchased within the past year showing several quality flaws such as misaligned door hinges and subpar coatings on their outdoor nema gear. Furthermore the company answers the phone to any custom consideration and today that is a plus to me. Their website has a security app sec, I only mention sources that Ive had positive results with.

[Gyro Gearloose 0]

Do you have the heater/fan add on with those domes? The spec sheet calls for an extra 20voltamps with that addition, which would put the range above 1amp per camera.

 

RickA,

 

None of these are using the heater / blowers since they are all inside. We will see if I need a heater / blower on the outside camera as the weather worsens.

 

At the same location I installed a Speco HT-7246IHR Intensifier dome but they don't call for a heater blower, in fact they don't even have a option for one. Why would one brand need one and another brand not?

 

In your original post you stated:"We connected this camera to a different brand of power supply & it started to work" When you swapped the PS was it local: single isolated transformer, near the cam or on the original power wire run? Aside from the current draw and related issues discussed perhaps you should check your power runs (lengths/voltage drop)

 

I used a damaged alarm panel to power the camera. I installed it at the DVR (at the farthest point from the camera). The wiring for most of the other cams was RG59u Siamese w/ 18ga power wire. This cam is at about 100ft but uses a 22ga wire (Something left over from an ADT Observation system). It goes up a couple of floors so I chose to leave it. I guess it adds about 10 or 15 ma to the current but I'm getting 13.4 vdc at the cam which is fine.

 

Gyro, there is still some high quality American gear being made... I try to buy American when I can (American labor needs to put food on their table too, our government seems to have forgotten that...unfair, one way trade agreements...etc)....here is a good source for quality PS http://www.bearpwr.com/

 

Lolo,

I looked at these power supplies but they all seemed to small. the largest I saw was 2.5A at 12vdc. Do they have off the shelf units that are higher power? I don't care if they have separate power out for each camera, I can just use a terminal strip if necessary.