Here is an antenna from 2003, the Gottingen Heart Antenna, whose only
similar incarnations appear to be a folded capacitive loaded equivalent)
the gull wing ridged waveguide horn -- and IIRC Kraus' exponentially
curved solid dipole drawing in /Antennas/.
That's a very easy question... MOVs are cheap and reasonably effective at both
protecting primary circuits and preventing transmission of spikes and spurious
signals into secondary circuits where they wreak functional havoc.
Few consumers would pay for industrially robust goods.
T
-
I would think the device only needs to pass the required surge testing of
EN61000-4-5 as well as associated EFT/Burst and Ringwave, if required.
Doug
Douglas E Powell
http://www.linkedin.com/in/dougp01
--Original Message--
From: Richard Nute
To: Doug Powell
To: EMC-PSTC
ReplyTo:
It's really a power thing too. (energy by time) If you hit the MOVs too
often with a 6kV pulse, they'll overheat and fail. If say you hit them
every 90s instead of every 30s, they'll likely survive a hundred hits.
___
In message
OFE46BE9DC.DA54D6BA-ON88257AD6.00657B8E-88257AD6.0067472A@US.Schneider-E
lectric.com, dated Sun, 16 Dec 2012,
ralph.mcdiar...@schneider-electric.com writes:
It's really a power thing too. (energy by time) If you hit the MOVs
too often with a 6kV pulse, they'll overheat and fail.
Some standards require considerably more than 1500V surge on mains input
(L-L and L-N and L-G). The expected over-voltage (from nearby lightning)
depends on service voltage (120/240 vs 277/480, etc) IEEE 1547.1 requires
6kV surge testing for static inverter used for distributed generation,
From a safety perspective, it's much better to design to minimum clearance
require w/o the MOVs and then to include them in the circuit. (e.g. what
happens of the MOV fails open?)
From an EMC perspective, L-C filters with a hi-Q, like those used for RFI
on mains input circuits, can increase
I want to add to that that any Hi-Q EMC filter is per definition a bad
emc filter.
EMC filters should never be steep, have a narrow frequency band, or
allow resonance.
Easy design rule: use small L and BIG C's. Small L's do better at High
frequency too !
Use low grade EMC ferrite as a core, no
In message FCA549BE3ECF9D4CB8CB8576837EA489140BC7@ZEUS.cetest.local,
dated Sun, 16 Dec 2012, ce-test, qualified testing bv - Gert Gremmen
g.grem...@cetest.nl writes:
Regarding the MOV: for professional appliances a fused MOV is common;
they
Mostly have a fused indicator or even output. In
In message
OF48DFA6EA.9932593A-ON88257AD6.0065FB4B-88257AD6.006A700E@US.Schneider-E
lectric.com, dated Sun, 16 Dec 2012,
ralph.mcdiar...@schneider-electric.com writes:
Some standards require considerably more than 1500V surge on mains
input (L-L and L-N and L-G).
We don't expect more than
If you pass the minimum requirements for surge in the environmental conditions
specified, you have done enough. Good design practice says install the MOVs
downstream of the EMI filter to buffer the surge with a small bit or
impedance.
If you want to go beyond the regulatory compliance needs
In message
1454929815-1355690903-cardhu_decombobulator_blackberry.rim.net-192443596
2-@b15.c21.bise6.blackberry, dated Sun, 16 Dec 2012, doug...@gmail.com
writes:
Good design practice says install the MOVs downstream of the EMI
filter to buffer the surge with a small bit or impedance.
Does
John,
The susceptible components in a filter are the Y and X capacitors.
Y are for line to earth connections. These are typically rated and certified
as Y1, Y2, etc. This rating is specific to the surge withstand capability in
the IEC component test standard. Similarly the X capacitors
In message
1745841055-1355694284-cardhu_decombobulator_blackberry.rim.net-247462401
-@b15.c21.bise6.blackberry, dated Sun, 16 Dec 2012, doug...@gmail.com
writes:
The susceptible components in a filter are the Y and X capacitors.
I am quite up to speed on that. My question applied to the
14 matches
Mail list logo
