Clean AC to processor

Hello all. I have a customer that wants to make sure I use an isolation XFMR for the AC power going to a CLX processor. He wants to make sure that a spike seen on the line is not carried to the processor. I always use a step-down then a filter to accomplish this, not saying I am right but it makes sense to me. Thinking back to many years ago, I believe an isolation transformer is nothing more than a XFMR with a windings ratio of 1, uncoupling the load side electronically from the line side? The nature of all XFMR's is inherently isolation (except for autotransformers) anyway, including step-downs, correct? I have been searching for an isolation transformer that steps down from 480 to 120 but nothing with the word "isolation" stands out. All the isolation transformers I see have the turns ratio of 1. Any advice I could get as to the best way to accomplish this would be greatly appreciated.....and a way to explain this to the customer. Thank you

You might look up 'Isolated Ground' system.

We have one where I work. It is a 480 to 120 volt transformer with a panel box. None of the circuits ground to the conduit or ground. All of the grounds are ran back to the panel box. The only place the system is grounded is the one ground wire from the panel to a ground spike driven into the ground right beneath the panel. (If I take loose that wire, the entire panel reads open with respect to ground.)

True story. Maybe two years after this was put in, some jackleg contractors electrician installing some other stuff attached one of this systems ground wire to something grounded someplace else. (Creating a 'ground loop'). In two days I had two computer systems corrupt files in them. I yelled and screamed and 'they' brought in a real electrician who found where the extra ground was and removed it. No more problems going on ten years now.
Poet.

To reduce noise passing through a transformer there needs to be an earthed screen between the windings, this tells it much better than I can:
http://www2.schneider-electric.com/...live/FAQS/123000/FA123947/en_US/Isolation.pdf
I did a search looking for companies that stated there was an electrostatic shield between windings, it took a while but found this company that show it as an option.
https://www.rexpowermagnetics.com/p...sformers/industrial-control-transformers.html

BryanG said:

To reduce noise passing through a transformer there needs to be an earthed screen between the windings, this tells it much better than I can:
http://www2.schneider-electric.com/...live/FAQS/123000/FA123947/en_US/Isolation.pdf
I did a search looking for companies that stated there was an electrostatic shield between windings, it took a while but found this company that show it as an option.
https://www.rexpowermagnetics.com/p...sformers/industrial-control-transformers.html

Click to expand...

Thanks for the info

If he is that worried, use a constant voltage transformer.
more expensive, but keeps the voltage constant, prevents spikes, brown outs.

james

These are what we use on processor power supplies.

http://www.solahevidutysales.com/mcr_hardwired_power_line_conditioner.htm

I started using DIN rail mounted UPS's a few years back as I like keeping the CPU powered up anyway, dropping out the output voltage with estops

http://www.apc.com/shop/us/en/produ...ith-Standard-Battery-500VA-120V/P-SUA500PDR-S

With the cost of any new AB CPU you need to protect it and the UPS was a win win for what I need to do as I need to keep timers running and the state of the machine in the 'cycle' so when power came back it would not lose its place in the cycle

We have been using Isolratrol's for 25 years now with no complaints or failures. Plus they don't generate any heat like the Sola.

I had a machine I connected my laptop to with a SLC5/03.

When I tried to connect with RSLinx it wouldn't see the UIC. Then I went to Device Manager and it wasn't there either. I tried unplugging it an putting it back in, then I got an Unknown USB Device popup. Also about that time I noticed the laptop's battery icon was flashing. When I clicked on it, it showed the battery was very low and not charging (it should have been full)

Thinking I now have to buy a new UIC and a battery I got a different laptop and connected to the SLC through DF1.

After I was done and in the office, out of habit I guess, I plugged the other laptop in to charge. Then it showed the battery was fully charged and good. I then tried the UIC in the office and it worked fine.

I took it back to the line and did some testing. If I ran the laptop on its battery the UIC connected fine - but if I plugged the charger into the programmer port in the control panel, the UIC suddenly failed and the battery shut down.

I talked the customer into letting me separate the programmer port, PLC and HMI to run through a line filter. Everything works fine ever since.

This line was a simple conveyor wash line, but next to it was a huge electroplating operation - I talked to their IT engineer and he said he had a big problem with computers in the area needing completely replaced, or a lot of hard drives, memory cards, video cards, etc. in that area.

I took that as a lesson and now include at least a line filter, if not a power conditioner, in the power for PLC's, HMI's and programming ports.

ACME also sells "power conditioning" transformers.
https://www.hubbell.com/acmeelectric/en/Products/Electrical-Electronic/Power-Quality-Conversion/Power-Conditioning/c/2144925

Just put a 24VDC power supply on the rack. 1756-PBxx

JaxGTO said:

We have been using Isolratrol's for 25 years now with no complaints or failures. Plus they don't generate any heat like the Sola.

Click to expand...

Can you supply a link?
Can't find "Isolratrol" transformers in google...

NetNathan said:

Can't find "Isolratrol" transformers in google...

Click to expand...

Probably meant "ISLATROL"...

NetNathan said:

Can you supply a link?
Can't find "Isolratrol" transformers in google...

Click to expand...

Yea it's made by Emerson:
https://www.digitaltele.com/emerson-islatrol-ic102-120v-ac-25a-sine-wave-filter


That's why I have this cup: