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Doug, Dave
This is not the first time the formulae and examples in 6.7 have been called
into question.
One of my customers raised a query about a year ago, and I forwarded the query
to the Chairman of the IEC TC for 61010, as well as the (BSI) Secretary
thereof, as attached - I received an acknowlegement from Mr Chapman but I
never received an answer!
There might well be misprints in this case as I found quite a few elsewhere on
an earlier occasion, as per a previous message to Mr Chapman, also attached!
Therefore I think you need to view the text of this edition of 61010-1 with
the proverbial "pinch of salt" :- if it doesnt "look right" then it probably
isn't!!
Regards
John Allen,
Technical Consultant
EMC and Safety Engineering
ERA Technology Ltd.
Cleeve Road
Leatherhead
Surrey KT22 7SA
UK
Tel: +44-1372-367025 (Direct)
+44-1372-367000 (Switchboard)
Fax: +44-1372-367102
From: drcuthb...@micron.com [mailto:drcuthb...@micron.com]
Sent: 04 November 2003 16:46
To: doug.pow...@aei.com; emc-p...@ieee.org
Subject: RE: IEC 61010-1:2001 section 6.7.3.2 Clearance Calculation
Doug,
I find it confusing. Good thing there are examples.
example b) gives the correct answer.
example a) does not look correct.
Reasoning:
1) F is solved incorrectly. It should be 0.297
2) The remainder looks correct. I get 20.5 mm (without interpolation)
With interpolation I get 18.4 mm.
Dave Cuthbert
Micron Technology
From: owner-emc-p...@majordomo.ieee.org
[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of POWELL, DOUG
Sent: Monday, November 03, 2003 2:48 PM
To: EMC-PSTC (E-mail)
Subject: IEC 61010-1:2001 section 6.7.3.2 Clearance Calculation
Has anyone tried to work through the two examples given in this section? In
trying to understand how to use the CLEARANCE = D1 + F(D2-D1) equation, I was
hoping to check my work with the examples that were given. Either I'm missing
something or these examples have some really fundamental errors.
In my application, I am attempting to calculate the basic clearance for a
working voltage of 1500 VDC with transients that peak to 1800V and ride on the
VDC. The final peak voltage is 300 Volts higher than the steady-state 1500VDC,
which apparently meets the 6.7.3.1 b) 2) criteria.
Please help!
-doug
end
Douglas E. Powell
Corporate Compliance Dept.
Advanced Energy Industries, Inc.
Fort Collins, CO 80525 USA
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--- Begin Message ---
For the attention of the following Officers of IEC TC66
Chairman: Mr. Cecil CHAPMAN
Grant Instruments (Cambridge) Ltd.
Mill Barn
Bassingbourn, SG8 5PP, UK
&
Secretary: Mr. N.A.R. BRADFIELD
British Electrotechnical Committee
Electrical Department - Floor 11-6
British Standards Institution
389 Chiswick High Road
London W4 4AL, UK
Dear Sirs
It has been suggested that we draw to your attention the following technical
and/or printing errors which appear in copies of BS EN 61010-1:2001 - and thus
presumably in EN 61010-1:2001 and IEC 61010-1:2001
1) Clause 6.8.4 "Voltage tests" & Table 9 "Test voltages for BASIC INSULATION"
(Page 52).
We are reasonably sure that there is a misprint in Column 1 "Clearance" of
Table 9 , as follows: The line entry between "1.0" and "2.0" is "1.4" but it
should be "1.5" (mm).
We believe that this is obvious from Table 8 "Clearance for measurement
categories II, III and IV" where "1.5" (mm) is mentioned in numerous places but
"1.4" is not mentioned at all.
Apart from anything else, 1.5mm is the category II minimum value for nominal
line voltages of >150V<=300V - which will be the mimimum value for a very large
amount of equipment.
Therefore the majority of users of the standard will have to start out by
interpolating in Table 9 - and may result in many mistakes in test voltages -
in fact interpolating from the existing values may result directly in test
errors.
Nevertheless, even if we are wrong about the need for the "1.4" entry, we think
that the test voltages for 1.5mm should be given as well.
Also. assuming that we are correct we do need the correct values for 1.5mm,
please could you find a way of making this information available in advance of
the long process of issuing an amendment to the standards
We also recommend that a critical review be made of all the values stated in
Table 9 as the existance of the above probable error brings in to doubt the
rest.
2) Clause 8.1.2 and Figure 4 (Page 63)
According to Clause 8.1.2, Figure 4 consists of two drawings called "Figure 4"
and "Figure 4a)" - but neither is actually labelled in the Figure to show which
is which!
3) Clause 9 and Figure 5 (Page 66)
There are several misprints in Fig 5 "Flow chart to explain the requirements
for protection against the spread of fire".
On the right hand side of the diagram there appear to be arrows missing between
the boxes for:
i) "Construction requirements for components 9.2.1 a)" and "ENCLOSURE
requirements 9.2.1 b)"
and
(ii) between "ENCLOSURE requirements 9.2.1 b)" and "Requirements for flammable
liquids 9.4 c), d) or e)".
Additionally, the Flow chart symbols in this diagram do not appear to conform
to some generally accepted principles, i.e should there not be "decision
("OR")" box symbols where alternative
routes are available (e.g. as in Fig 10).
4) Clause 9.3 and Tables 13 & 14 (Page 69)
In 9.3 b) 2) the reference should be to Table 14 rather than Table 13.
5) Clause 10.5.3 and Figure 8 (Page 75)
The Ball Pressure Test equipment is illustrated and referred to, but all the
dimensions for the equipment have been omitted.
Either these dimensions shall be placed on the diagram, or reference shall be
made to the appropriate IEC/ISO test standard (as is done for the Vicat test)."
We would be grateful for a prompt acknowledgement of these statements and
queries.
Yours faithfully
John Allen
(Daytime contact phone number 01372-367025)
&
Andrew Wood
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