Figure 3 shows an evaluation board that uses one of RECOM’s SMD DC/DC converters to provide isolated bus power. This is one of the reasons why isolated CAN-bus systems are often used in heavy industrial automation plants and production processes. Any electrical interference is ignored by the differential bus topology, without the danger of external fields inducing an overall current flow in the wiring. Tripp Lite IS250HG Isolation Transformer 250W Medical Surge 120V 2 Outlet TAA GSA 10 25013390. As both ends of the bus are isolated, the transmitter and receiver can sit at different ground potentials without problem. PHC ISO-1000 1000 Watts AC Isolation Transformer with Pass-Through Grounding 12 B&K Precision 1604A Single Output Isolation Transformer, 4' H x 4' W x 5.5' D 14 12990 FREE delivery May 3 - 4 Only 10 left in stock - order soon. The CAN-bus specification does not specify that the bus wiring must be isolated, but in practice, isolating the interface eliminates many potential sources of error or interference with the data transmission. The isolation provides added security against interference or increases reliability, but is not safety-related.Ī good example is a CAN-bus data communication system. In these applications, an isolation fault would not cause injury or serious damage to the equipment, or often even stop the application from working. Typical applications for functional isolation converters include non-safety-critical systems, where the isolation is primarily used to break ground loops, block conducted interference paths or to provide a change in functional ground reference voltage. This method has the advantage of being low cost and yielding a very compact-sized transformer which, despite the small size, can withstand up to 4kV DC isolation voltage testing, but with limited duration and as a non-repetitive test.įigure 2: Ring core transformer with functional isolation So how do these classes translate into practical transformer construction?įor functional isolation, transformer primary and secondary windings are typically wound directly over one another, relying on the thickness of the wire lacquer for insulation (Figure 2). Reinforced – a single barrier equivalent to two layers of Basic insulation.Supplementary - an additional barrier to basic, required by agencies for redundancy.Basic - the isolation offers shock protection as long as the barrier is intact.Functional - the output is isolated, but there is no protection against electric shock.That cable will connect to the home power socket. I have a cable with a 3 pin plug ready to attach to the IsoTran. I thought if I need further ventilation I can remove the lid and place some form of rigid metal mesh in-situ. For DC/DC converters, the most commonly used classes are: The actual box also lifts off from the base once a few screws are removed. The isolation grade is dependent on the robustness of the isolation barrier. and if someone here knows where I can find some schematics for an op-amp di box with ground lift switch, that would be much appreciated.Figure 1: Some different ways of using an isolated DC/DC converter why not?īear in mind that I'm quite ignorant about all this stuff, so please tell me your thoughts about it but keep it simple. Now I don't know if the TL072CP is the best option out there (if there are better op amps for this particular purpose, I'd be glad if you named them), but if I can build a decent di-box and save loads. I mean, it would be way waay cheaper, some say there are even advantages using the opamp active di configuration vs the transformer passive di. Well, considering that for example a 10 pcs lot of TL072CP by texas instrument would cost like 10 dollars including shipping from the US (taxes would be like 2 dollars). Now, I've heard that you can do without the transformer and use a dual channel JFET op-amp to make a phantom powered di box instead. Well, that would be the major expense, and it looks like I'd end up with a good di box. be careful that you fit an appropriate 240v output socket on the second one instead of a a plug with live pins exposed. and I live in EU so no annoying importing taxes). The cheapest way here in the U.K is to buy a couple of second hand 240-110v power tool site transformers and connect the output 110v from one to the 110v winding on the other, that way you get 240 out again double isolated. I found that buying the transformer required from the UK would cost me about 46£ including shipping (the equivalent of about 66 dollars, not too bad. I've read a little bit of stuff over the internet about diy di boxes and had eventually found a project that looked interesting to me ( DI-box my work horse from 1975 ) I've never done anything before but a friend of mine (who's got some circuitry blah blah knowledge and can solder!) is willing to help. Hi there, need some advice from you guys.īear in mind I'm falling in the trap of diy.
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