Hi
I saw that EN 55035 is listed in the OJ list of Harmonised Standards for the
RED.
Any thoughts regarding the EMCD since no new list of harmonised standards has
been published for the EMCD since 2016.
Regards,
David Shidlowsky | Technical Reviewer
Address 1 Bat-Sheva St. LOD 7120101 Israel
Te
Hi John:
Depends on what limits are set for insulation resistance and electric strength
current.
For example, assume the insulation resistance limit is 100 megohms and the
measured insulation resistance is 10 megohms. Failure.
If the electric strength test is 3,000 volts, the curr
IR and D/EW are affected differently by capacitance, tracking, and other things.
IR can be both qualitative and quantitative; that is, a measurement of the
property of the insulator, as the test conditions and levels are all defined.
IR is typically done within the rated or 'normal' operating co
Hello, Rich. This puzzles me:
Or, it can fail the insulation resistance measurement yet pass the
dielectric strength measurement.
how can that happen?
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates www.woodjohn.uk
Rayleigh, Essex UK
On 2018-02-19 21:53, Richard Nute wrote:
O
Hi Paolo and the group,
It turns out I did reply to the SI-List but either not to this list or in html
mode and it got rejected. It takes me more effort to reply to this group as I
have to reconfigure my email program to use this list in 1970s style text mode
and then back again for the rest of
Hi Scott:
Analog resistance measuring equipment puts a known voltage across an unknown
resistance and measures current (the meter is calibrated in ohms). It is an
implementation of Ohm’s Law.
Measuring high resistances, e.g. more than 10 megohms, requires a higher
voltage to get enou
I think that wood was discontinued a very long time ago. But other
materials were certainly hygroscopic. Military-grade ebonite, used for
mechanical applications, was polished with tin foil at one time, which
rather impaired its insulating qualities. Also, creepage and surface
contamination w
As far as I understand, this requirement was needed in the time that insulation
materials
might have hygroscopic properties. Insulation materials as wood were common in
the past.
If they were not suitably treated, in humid circumstances insulation might drop
to unacceptable levels.
Ger
The flash test is necessary because there are high-voltage pulses on the
electricity supply caused by switching operations and distant lightning.
It is very likely that a product that fails the insulation resistance
test would fail the high-voltage test as well. But it is not
inevitable; a 1.8
John,
I almost forgot the Megger gear that I tried it once in the lab when I studied
radio engineering. Thereafter I am using battery-operated tester and now more
and more multi-purpose testers including it into one unit.
The main reason why I raised this query is that the flash test giv
I’d like to second John’s query, as I haven’t seen the explanation either.
If it has been posted, are EMC-PSTC postings being lost somewhere? I have
checked our company spam filters!
Regards,
Mark
From: John Woodgate [mailto:j...@woodjohn.uk]
Sent: 08 February 2018 14:15
To: EMC-PSTC@LISTSERV
The test is very old, and pre-dates the high-voltage test by very many
years. You mentioned 'Megger' in your other post, yes, that was how it
was done. (A Megger (brand name) was/is a type of magneto with an
ohmmeter attached. The stable output voltage required for the ohmmeter
is achieved by a
Thanks for your sharing experience! Did you conduct the flash test that
normally is over 1,250 Vac by that time? Probably a megger tester is more
portable for onsite testing than flash test as an alternative.
Scott
From:
Date: Monday, 19 February 2018 at 2:50 PM
To: 'Scott Xe' ,
Su
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