I can see using a PLL with a long time constant to obtain immunity from line
noise. But If the line zero crossing shifts abruptly the SCR fires to one
side of zero crossing. An expensive solution is to run your equipment off of
a power conditioner that performs the AC-DC-AC function. Pretty expensive.
Dave Cuthbert
From: [email protected] [mailto:[email protected]] On Behalf Of Kunde, Brian
Sent: Wednesday, November 08, 2006 9:43 AM
To: David Cuthbert; [email protected]
Subject: RE: Worst Case AC Power Conditions
Dave,
Thanks for the reply.
I should have explained further. Our equipment is designed to work only
in the 230V nominal voltage range at both 50 and 60 hz. Our equipment
has furnaces that we must regulate the temperature within a very tight
spec. To do this we must fire control relays (SSRs) either at the zero
crossing or use phase control method. These methods require us to
monitor the AC line so to fire the SSR properly. As you can image, such
methods would be susceptible to AC line noise, harmonics, dips, etc.. So
we design immunity to such noise into our products, but sometimes it is
not enough.
The other Brian
From: [email protected] [mailto:[email protected]] On Behalf Of David
Cuthbert
Sent: Wednesday, November 08, 2006 11:30 AM
To: Kunde, Brian; [email protected]
Subject: RE: Worst Case AC Power Conditions
Brian,
When I worked for a well-known instrumentation company our universal
power line requirement was, if I remember correctly, 80 to 270 VAC. If
one could achieve more it was good. I designed one that would reliably
operate from 75 to 280 VAC. This covered 100 V Japan on up with margin.
Our products were sometimes used in the field with generators and I
believe the extra margin built in helped us avoid field complaints. Our
off-line bulk capacitance, as well as the DC output capacitance was
unusually large to allow for long line dropouts.
Of course building in extra margin can raise the cost of design and
manufacturing. In our case it was reflected in higher capacitor cost and
lower power density. The upside was a slow but steady improvement in our
reputation and the ability to continue to command a price premium for
our products.
Dave Cuthbert
Senior Test Engineer
NARTE Certified EMC Engineer
Linear Technology Corporation
*******************Internet e-mail Confidentiality
Footer******************* This e-mail transmission, and any documents,
files or previous e-mail messages attached to it may contain
confidential information that is legally privileged. If you are not the
intended recipient, or a person responsible for delivering it to the
intended recipient, you are hereby notified that any disclosure,
copying, distribution or use of any of the information contained in or
attached to this transmission is STRICTLY PROHIBITED. If you have
received this transmission in error, please immediately notify me by
reply e-mail, or by telephone at (719) 593-1579, extension 261 and
destroy the original transmission and its attachments without reading or
saving in any manner. Thank you.
=======================================================
From: [email protected] [mailto:[email protected]] On Behalf Of Kunde,
Brian
Sent: Wednesday, November 08, 2006 7:15 AM
To: [email protected]
Subject: Worst Case AC Power Conditions
Greetings,
1. Can anyone provide specifications for a "worst case" real world AC
power line condition in which an apparatus is expected to operate
properly in (pass/criteria A)? This would encompass a combination of
harmonics, voltage variations, frequency variations, etc..
2. Also, if anyone has a program for a California Instrument CTS
system with a 5000ix power supply that could test for a "worst case" AC
line condition, that would be helpful. I have heard that some companies
have developed such a custom program to simulate poor power conditions
>from different parts of the world. Such a program would operate with the
the provided CIgui32 program.
3. Can anyone recommend an AC Power Line analyzer that we can just
plug-in and it will analyze the AC power conditions at different
customer locations? Then we could take the results and program our
5000ix power supply to simulate those conditions in our lab.
The reason I'm asking is that from time to time we have experienced
problems in the field due to with poor AC power line conditions at some
customer locations even though we test and comply with the standard
tests that are required for CE (surge, burst, dips, etc). We want to
develop an internal test standard that will minimize problems in the
field.
Thank for any help or advice you can offer.
The Other Brian.
-
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
-
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
-
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
-
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
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please visit http://www.messagelabs.com/email
______________________________________________________________________
