Hi, Pat.
This is another case where prior planning prevents pretty perplexed people (to
paraphrase the original).
Some years ago. I too was involved with EMC testing of "high-power medical
equipment that is used on an intermittent basis." Testing would have taken
months and cost millions of dollars had we been restricted to normal operation
and duty cycles.
The cure for this is, before testing is even begun, to plan on not only enough
equipment to test and destroy, but also special firmware and software to
ensure that, for EMC testing only, everything that can cause interference, or
if testing for susceptibility, problems when it fails to work, runs as close
to continuously as can be arranged, even if this is not possible for users
themselves as sold.
One must of course bear in mind that this could cause the equipment under test
to fail by itself, and since we can't have egg in our beer (isn't this
forbidden in the EU?) sometimes you'll have to slow down the system so the EUT
can survive.
Added: It is really cool to see people's lives saved by something one has
participated in bringing to market, you know?
Cheers,
Cortland
KA5S
----- Original Message -----
From: <mailto:[email protected]>
To: [email protected]
Sent: 11/13/2008 12:44:58 PM
Subject: Test setup for equipment operated intermittently
Hi,
I need to run EMC tests on a piece of high-power medical equipment that
is
used on an intermittent basis. The run time is about 15 seconds to 2 minutes
on-time, followed by about 10 minutes off-time. This is comparable to typical
system usage. This causes problems with EMC testing, since you normally need
a longer observation period.
1) The equipment could be operated continuously, but extra cooling
would have
to added to the test setup, which is not part of a typical system. In the
spirit of regulatory intent would this be considered overtesting?
2) Could testing be done at the highest power level that allows
continuous
operation?
What load conditions/test setup are appropriate for an application like
this?
!
Pat Lawler
EMC Engineer
SL Power Electronics Corp.
-
This message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. Website: http://www.ieee-pses.org/
To post a message to the list, send your e-mail to [email protected]
Instructions: http://listserv.ieee.org/request/user-guide.html
List rules: http://www.ieee-pses.org/listrules.html
For help, send mail to the list administrators:
Scott Douglas [email protected]
Mike Cantwell [email protected]
For policy questions, send mail to:
Jim Bacher: [email protected]
David Heald: [email protected]
All emc-pstc postings are archived and searchable on the web at:
http://www.ieeecommunities.org/emc-pstc
