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Does anyone know off hand the isolation distance between primary and
secondary on a EI tranny? i thought it was something like 6mm?
OK. I do not have access to the standard but will attempt to describe."Geoff C"
Does anyone know off hand the isolation distance between primary and
secondary on a EI tranny? i thought it was something like 6mm?
** Your question is far too vague.
AS3108 gives " Distances through insulation between input and output
circuits." ( which applies to a transformer ) as being a little as
0.1mm ( ie 4 thou) for a 250 volt AC supply.
The VA rating of the transformer come into the figure as does the type
of insulation used.
How about you ask for the info you are really after?
....... Phil
Does anyone know off hand the isolation distance between primary and
secondary on a EI tranny? i thought it was something like 6mm?
** Your question is far too vague.
AS3108 gives " Distances through insulation between input and output
circuits." ( which applies to a transformer ) as being a little as
0.1mm ( ie 4 thou) for a 250 volt AC supply.
The VA rating of the transformer come into the figure as does the type
of insulation used.
How about you ask for the info you are really after?
OK. I do not have access to the standard but will attempt to describe.
Transformer is mains and approx 300VA peak, 150VA average with multiple
secondaries, elecrostatic screen and 120/120 primary for international
voltages. Max secondary winding is 285 volt.
Centre leg 40x73mm, stack height 53 mm. Inter winding insulation is mylar
tape, (the yellow stuff) with elephantide type wrap. I am evaluating a
new supplier of this tranny and would like to give the go ahead to the
manufacturer for an initial run if it is OK. I will do hi-pot testing
after I unwrap and check construction. I would like to know the legal
requirement for the creepage distance from primary to secondary winding.
No, measuring equipment."Geoff C"
Does anyone know off hand the isolation distance between primary
and secondary on a EI tranny? i thought it was something like 6mm?
** Your question is far too vague.
AS3108 gives " Distances through insulation between input and output
circuits." ( which applies to a transformer ) as being a little as
0.1mm ( ie 4 thou) for a 250 volt AC supply.
The VA rating of the transformer come into the figure as does the
type of insulation used.
How about you ask for the info you are really after?
OK. I do not have access to the standard but will attempt to
describe.
Transformer is mains and approx 300VA peak, 150VA average with
multiple secondaries, elecrostatic screen and 120/120 primary for
international voltages. Max secondary winding is 285 volt.
** For a valve amp ??
Yes, overwound, it is not a split bobbin.Centre leg 40x73mm, stack height 53 mm. Inter winding insulation is
mylar tape, (the yellow stuff) with elephantide type wrap. I am
evaluating a new supplier of this tranny and would like to give the
go ahead to the manufacturer for an initial run if it is OK. I will
do hi-pot testing after I unwrap and check construction. I would like
to know the legal requirement for the creepage distance from primary
to secondary winding.
** Still far to vague.
1. Is the tranny of "overwound" construction ?
Yes2. Is there a plastic bobbin ?
No, earthed equipment3. Is it intended to meet class 2 requirements ?
It varies, 2 layers or more mostly. Have not yet measured the thickness.4. Is the mylar layered ?
Yes, 2 wraps.5. Is the paper wrap between primary and secondary?
I am aware of the distinction, and it is creepage I am wanting to knowBTW
You seem to think that "creepage" and "clearance " are the SAME as
"distance through insulation...."
They are not.
....... Phil
Transformer is mains and approx 300VA peak, 150VA average with
multiple secondaries, elecrostatic screen ..
Yes, I see where you're coming from. Sheet copper, between pri and sec,"Geoff C"
Transformer is mains and approx 300VA peak, 150VA average with
multiple secondaries, elecrostatic screen ..
** That ES screen complicates the situation.
Normal creepage and clearance rules go out the window.
Describe it .
........ Phil
"Phil Allison"
Transformer is mains and approx 300VA peak, 150VA average with
multiple secondaries, elecrostatic screen ..
** That ES screen complicates the situation.
Normal creepage and clearance rules go out the window.
Describe it .
Yes, I see where you're coming from. Sheet copper, between pri and sec,
2l ayers of mylar tape and a single paper on each side. 40 mm width and
centred in bobbin. Layer of paper and mylar tape underneath the end to
prevent shorted-turn.
Thanks."Geoff C"
"Phil Allison"
Transformer is mains and approx 300VA peak, 150VA average with
multiple secondaries, elecrostatic screen ..
** That ES screen complicates the situation.
Normal creepage and clearance rules go out the window.
Describe it .
Yes, I see where you're coming from. Sheet copper, between pri and
sec, 2l ayers of mylar tape and a single paper on each side. 40 mm
width and centred in bobbin. Layer of paper and mylar tape underneath
the end to prevent shorted-turn.
** Long as that sheet of copper is the same width as the primary
winding you have complied.
Often, tranny makers will just wind a singe layer and use that as a
ES shield - being careful not to join the ends !
....... Phil
Does anyone know off hand the isolation distance between primary and
secondary on a EI tranny? i thought it was something like 6mm?
Domestic or light industrial, low to average pollution degree.
Here
http://www.saiglobal.com/shop/Script/Details.asp?DocN=stds000011541
Buy the standard and all your questions will be answered!
I have lots of standards here, but we dont make transformers and have noHere
http://www.saiglobal.com/shop/Script/Details.asp?DocN=stds000011541
Buy the standard and all your questions will be answered!
JG
"Geoff C" <notinterestedin@spam.com> wrote in message
news:Xns97A173B7A327Ftestnospamcom@61.8.0.29...
Does anyone know off hand the isolation distance between primary and
secondary on a EI tranny? i thought it was something like 6mm?
Domestic or light industrial, low to average pollution degree.
won't actually give you the information that you need, but will reference 15The reality is, you wind up $130 poorer and likely more confused that you
ever imagined.
$130 would be lovely. If it's like most other standards these days, it
Here
http://www.saiglobal.com/shop/Script/Details.asp?DocN=stds000011541
Buy the standard and all your questions will be answered!
JG
"Geoff C" <notinterestedin@spam.com> wrote in message
news:Xns97A173B7A327Ftestnospamcom@61.8.0.29...
Does anyone know off hand the isolation distance between primary and
secondary on a EI tranny? i thought it was something like 6mm?
Domestic or light industrial, low to average pollution degree.