Yes, I see a problem , Lightning spikes and the full peak mains
voltage when the mains is switched on at its voltage peak will
pass straight through your capacitors causing a safety hazard
and may destroy the insulation of the transformer if it is
not rated for this voltage.
Nick Rouse
----- Original Message -----
From: Pierre SELVA
To: Forum Safety-emc
Sent: Friday, January 11, 2002 5:18 PM
Subject: TR: 60950 - Insulation between mains and secondary with
capacitors
Hi forum members,
I would like to know your meaning on the following :
The concerned product is in the 60950 scope (EN, UL or IEC). I would
like to make the insulation between the mains and the secondary without
transformer, but only with capacitors (X rated). In fact, I need to use only
the high frequency signals transmitted on the mains. In this case, the
capacitors are considered as short circuit, and the 50 (or 60) Hz is cutted
by caps.
The circuit is as follow :
C T1
---------------| |-------------+ +-----
Mains + + Secondary part
---------------| |-------------+ +------
C
C are X rated capacitors
T1 is only a signal transformer (not use for galvanic insulation)
My questions are :
- Is this insulation correct according to reinforced insulation
requirements ?
- May I use only one caps for C, or 2 serial caps (in case of first
default) ?
- Do you see other critical points regarding 950 requirements ?
Thanks a lot for your contribution,
Best regards,
Pierre
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