Transformer grounded - why?

It depends on the circuit. If a 4 diode bridge is used, the secondary is not grounded. ONe common way is just to use a halfwave rectifier. If this is done, then almost always the secondary is grounded.. Moat refferances to voltaes are taken to the cahssies ground.

The secondary of the transfromer is grounded as a safety factor also. If for some reason the secondary is not grounded and then it becomes grounded to the frame, the frame will be at a high voltage. If the transfromer secondary is grounded and a short hapens internally, the fuse should blow.

Where ?

Graham

"Ralph Mowery" wrote in news:msmMg.9207$ snipped-for-privacy@newsread3.news.pas.earthlink.net:

But then shouldn't we just ground the frame?

Eeyore wrote in news: snipped-for-privacy@REMOVETHIS.hotmail.com:

I read it in a book. It says that one end of the secondary could be grounded.

It depends *entirely* what you're doing. It's actually often very bad practice to ground directly at the transformer itself.

Graham

On Sat, 9 Sep 2006 10:23:46 +0000 (UTC), in message , qwerty scribed:

"Could" and "should" describe fundamentally different intent. As someone else has said, it depends on the application. For instance, a common use of a transformer is isolation between test equipment and equipment under test. In this case, the secondary is not "grounded" because it is desired to separate the reference of the measurement device - perhaps an oscilloscope - from the device under test "ground."

What book are you reading?

If the primary and the frame are grounded but the secondary is not the potential between the secondary and the other parts can become high enough to break down the insulation and cause further failures.

You have to learn to think, "What will happen if ....?"

yes, now your rewording it.. it "could" be grounded.. what that means in terms that i think you might understand is that the xformer generates an isolated voltage energy source with one could connect/ground one of the secondary to the original source/ground with out a shorting problem.. for example. lets assume you have a little circuit that generates and oscillator that inputs its signal into a transformer. now on the secondary one could connect one of the legs to either the ground or high (Vcc) side of the original energy source used for the oscillator circuit with out shorting. its like using 2 separate cells/batteries. now, you may not want to do this with an Auto Type xformer.. you will them most likely come into some problems since these types of xformers do not give you isolation in that sense. they do not have a secondary winding of that nature.

Go boil your head in a vat of HF.

Graham