Sunday, September 18, 2011

Isolation Transformers Small transformers which help prevent big problems


There are many types of transformers in use with AC power to raise or lower the voltages but one of the more interesting ones is an Isolation Transformer which is used in circuits to reduce noise and isolate power loads and provide safety from line shocks. See http://en.wikipedia.org/wiki/Isolation_transformer for construction details.
I use Isolation transformers all the time at the WAVL to help keep noise from getting into audio equipment especially when you have equipment tied to each other that are hooked into 2 different phases of the power which can produce an undesired circulating current and blow out equipment.
Keeping in mind what Isolation transformers can do with noise they also can help in other situations as well. I have Mini Storage facility in Richland Pa. which has 44 separate color-day/night cameras watching over the property and remote viewed over the internet .There are even cameras in the entry and exit keypads which take video of who is using the keypads and records there storage unit number on the video which is helpful should one of many commercial clients who store items here temporarily need to know which one of there employees accessed there unit during the day. all cameras can see in the dark as they have Infrared emiters and special low lux lens. and we used special Baluns which allows Cat 5 cable to be used instead of coax which offers additional surge and noise protection as the wire is twisted. It also cut down by 3/4 the amount of space traditional coax would have taken in the conduits.
With the property being so large we had to get power from 2 different sources because of the long lengths which caused voltage drops which presents a problem.Ideally you always want cameras all on the same phase of power so you do not get noise and ground loops etc which can effect cameras. But that was not possible here 2 different meters feed the property. So the solution install an isolation transformer unit ( right in picture) which you can see in the above enclosure which was being tested to make sure it worked before we buttoned all the wiring up. and made it permanent. By using the isolation transformer we had a clean 120 volts AC we could transform down to 24Volts (left in picture) with out the worry of a ground loop or circulating currents between the two different power sources. We also installed Ditek CCTV surge protection on each cameras input to the recorders and on each recorders AC outlet plus installed battery backed up UPS units to supply clean power to the recorders. in case of power failure We also made sure all the grounding was unified to prevent step voltage as well. In all the extra precautions cost around $900.00 but it is protecting $45,000.00 in cameras and recording equipment where lightning is always a possibility with all metal storage buildings sitting on a flat plain high on a hill.
So far the setup has worked and troubles are minimized compared to problems previous owner had before we added all the extra cameras and protection as they where always blowing out cameras from storm damage.

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