Galvanic isolation - where to get info to learn more??

leitmotif

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I am seeing this term "galvanic isolation"

I remember in early 70's when the magic marketing phrase was "electronically controlled".

Is this galvanic isolation more marketing?

So I tried to research and found from Wikipedia
http://en.wikipedia.org/wiki/Galvanic_isolation
That two examples are a transformer (not autotransformer) and opto isolaters. I understand both and trust them.

I looked into IEEE and found
http://findarticles.com/p/articles/mi_m0BRZ/is_9_19/ai_57778456/
Appears to be mostly applied to computers - good stuff but not directly applicable to me.

I did "search forum" here and found little info.

Two possible applications where this has serious implications for me.
1. Developing computer controlled office heater using basically resistance heater. Power supplied by 120 VAC line. How do I ensure for five year life that I do not electrocute someone because some solid state gizmo in controller failed?
My first choice is a transformer then rectifiers mostly because that is what I know best.

2. Electric vehicle where the main "traction battery" is 325 VDC and may have a charging voltage up to 400 or so. This battery is ungrounded. I want absolutely no 325 VDC anywhere in passenger compartment or in dash
BUT I must have some control, instrument and display of traction battery for driver. Transformer is out of course and I assume opto isolater also. SO what do I use here
AND how do I be an informed consumer and know the product I am buying is going to do what I want.

QUESTION
Where do I find info on what this galavanic isolation means so that I really know what I am doing?

Dan Bentler
 
Your first application can use transformer isolation and should work well. Use a safety ground. Second application sounds like a DC-DC converter application, possibly custom. These are available with 3 mode isolation, input to ground, output to ground and input to output. A search for DC-DC converters should give you plenty of options.
 
At the root level it is the isolation of dissimilar metals to prevent chemical and/or electrical reactions.
 
Yes a 325 to 12 VDC DC DC converter is another application. For that and charging I am thinking MG sets using alternators.

So it appears that if I want COMPLETE and total isolation I can only use transformer, photo opto isolator or MG set.

Anything else solid state etc I need to allow for possibility of leakage.

Dan Bentler
 
Note that in order to get electrocuted, your body need to touch two objects inbetween is a difference of electrical potential. I.e., you can sit on a 13Kv live aerial line, you will be OK, but if somebody exteds you a ladder, that's trouble. And then, there is grounding, were you connect objects that can be toched to the ground potential. To make it even better, use a GFCI device.
 
My understanding of Galvanic isolation is "potential isolation/ interface".

An example would be equipment in a potentially explosive atmosphere. An intrinsically safe unit of some kind needs to be connected to the outside world. A galvanic isolator (Mounted outside the explosive atmosphere)ensures that the potential from you plc cannot be present within the explosive atmosphere.
 

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