In message <[email protected]>, dated Thu, 9 May 2013,
John Woodgate <[email protected]> writes:
Second, the last note in A.14 says that Pst and Plt are to be
determined analytically. As I have done the calculations don?t seem
to be very different from the measured values (as long as the source
is stiff enough to handle the inrush.) It does not seem to adjust the
limits at all. Am I seeing this correctly?
I agree that is a bit obscure and I will ask the person 'in charge' of
the standard. Don't hold your breath.
I asked three questions:
1. Is A.14 the right clause to apply? Could A.8 be applied?
ANSWER: I believe that A.14 is correct; A.8 is based on very short time
and infrequent operation of food mixers, whereas A.14 is relevant for
equipment that is in more frequent operation.
2. Why do P_st and P_lt have to be 'analytically evaluated' rather than
read from the flickermeter?
ANSWER: I believe that the reason for this is to account for cycle times
that are less than 120 minutes, but I am not 100% certain. I would be
comfortable for the results to be recorded by a flickermeter.
3. How can the sentence be interpreted when the manufacturer can't state
a number of cycles per hour?
ANSWER: Difficult to know what to suggest: I would recommend looking to
set an average number of operations per hour, but clearly this is open
to local interpretation. From the manufacturers perspective they should
be looking to ensure that their products do not cause interference with
other equipment, if they don't there is a risk that users will be
subject to complaints which they will ultimately pass back to the
manufacturer.
I think the third answer indicates that the standard needs improvement.
But it has just been updated, so no-one will want to change it soon. For
Europe, this is a case where involving a Notified Body may be the safest
course of action.
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
They took me to a specialist burns unit - and made me learn 'To a haggis'.
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
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