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Transformer grounded - why?

Q

qwerty

Jan 1, 1970
0
I read that the secondary of a high voltage transformer should be
grounded. Why? Will it still work if it's grounded?
 
R

Ralph Mowery

Jan 1, 1970
0
qwerty said:
I read that the secondary of a high voltage transformer should be
grounded. Why? Will it still work if it's grounded?

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.
 
Q

qwerty

Jan 1, 1970
0
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.

But then shouldn't we just ground the frame?
 
E

Eeyore

Jan 1, 1970
0
qwerty said:
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
 
A

Alan B

Jan 1, 1970
0
I read it in a book. It says that one end of the secondary could be
grounded.

"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?
 
H

Homer J Simpson

Jan 1, 1970
0
qwerty said:
But then shouldn't we just ground the frame?

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 ....?"
 
J

Jamie

Jan 1, 1970
0
qwerty said:
I read it in a book. It says that one end of the secondary could be
grounded.
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.
 
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