RE: Coatings for Ferrite Tiles?
I believe that for the higher frequencies, 1Ghz and above approximately, some sort of Styrofoam is added to the tiles to improve performance in that region. Don't know much more about it than having stood around in some really big semi-anachoic chambers with ferrite and observed the panels that were placed in front of the ferrites panels. They seemed to be small 1 foot square panels that when installed gave the chamber the appearance of being in the holo-deck of the Enterprise. The chamber manufacturers may have some useful information for you. They probably will have a purchase requisition right behind it, so I would do a web search first. Gary -Original Message- From: Ehler, Kyle [mailto:kyle.eh...@lsil.com] Sent: Monday, October 04, 1999 7:40 AM To: Lacey,Scott Cc: EMC and Safety list Subject:RE: Coatings for Ferrite Tiles? Hi Scott, I applied 1 bead board (styrofoam) in 4X8 sheets. After many trials with double sided carpet tape, foam tape, silicone rubber compound (RTV), etc. I found that 'Liquid Nails -Project' (latex based -non solvent) applied with a caulk gun to reliably hold the panels in place. I used a 2 dollop in each corner and one in the center of each panel. This was fairly cheap and quick to apply, but getting 40+ sheets of foam into the back of a pickup and then into the facility (on a breezy Kansas day) quite a challenge. These panels easily break, but patching them isnt too bad if you can catch and retrieve the bits...downwind 1Km. Not only does it aid with the light level, but it also damps the acoustic chatter and just feels warmer.. N'yuck, n'yuck, Kyle -Original Message- From: Lacey,Scott [SMTP:sla...@foxboro.com] Sent: Friday, October 01, 1999 1:26 PM To: 'emc-p...@ieee.org' Subject:Coatings for Ferrite Tiles? To the group, Can anyone recommend a paint or other (light colored) coating that can be applied over ferrite tiles? The lighting in the bat cave (shield room) is rather grim. It can be very difficult to see when working inside of a cabinet. Photos of test setups would also look better if there were less contrast with the background. Scott Lacey - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Screen Dimensions - Fire Enclosures
Hi, See Annex A.5, Hot Flaming Oil test. I have never done this test, but I have the ladle. Good luck. Ned Devine Entela, Inc. Program Manager III Phone 616 248 9671 Fax 616 574 9752 e-mail ndev...@entela.com -Original Message- From: John Juhasz [ mailto:jjuh...@fiberoptions.com mailto:jjuh...@fiberoptions.com ] Sent: Monday, October 04, 1999 10:39 AM To: 'emc-p...@majordomo.ieee.org' mailto:'emc-p...@majordomo.ieee.org' Subject: Screen Dimensions - Fire Enclosures Hi group. With reference to UL 1950 3rd. Ed., Table 15 (size and spacing of holes in metal bottoms of fire enclosures) , I would like some opinions . . . the largest size listed in the table is 1.00mm minimum metal thickness, 2.00mm maxhole dia., and 3.00mm minimum center-center hole spacing. If my metal thickness was greater (1.27mm), and my center-center hole spacing was 4.75mm, could I not go to a larger hole (3.175 - .125)? The reason I pose this question is that the dmensions I was thinking about using are for a 'standard' punch that a sheet metal fabricator would have. UL told me that what's they won't consider it because it's not listed on the chart. I am trying to tell my mechanical designer to use standard perforated stock which falls within the UL guidelines (there is stuff readily available) but he needs more airflow (without fans) . . . Has anyone been there? John Juhasz Fiber Options Bohemia, NY - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Screen Dimensions - Fire Enclosures
Hi John: the largest size listed in the table is 1.00mm minimum metal thickness, 2.00mm maxhole dia., and 3.00mm minimum center-center hole spacing. If my metal thickness was greater (1.27mm), and my center-center hole spacing was 4.75mm, could I not go to a larger hole (3.175 - .125)? The basic requirement is found in Annex A.5, Hot Flaming Oil Test. Table 15 lists a set of hole diameters and center-to-center distances between holes as a function of metal thickness. These combinations are such that hot flaming oil will extinguish when passing through the holes. The oil does not burn at room temperature. It must be heated before it will ignite. The burning oil is poured onto the perferated sheet metal. The combination of hole diameter, center-to-center spacing, and metal thickness combine to cool the oil and exclude oxygen when the oil passes through the oil such that the oil that passes through the holes ceases to flame. The extinguishing process is twofold: 1) The bottom surface of the oil film is cooled by the available metal surface. The top surface of the oil is heated by the flames and continues to burn. 2) As the oil passes through the hole, the hole actually fills with oil such that oxygen does not pass through the hole and thereby does not support combustion to the cooled oil that passes through holes. So, the thicker the metal, the more cooling. The larger the hole, the more likely the flame will follow the oil through the hole. 2 mm is about the largest diameter hole that will not allow the flame to pass through. So, you will need to rely on cooling alone. The hole-to-hole spacing and the metal thickness will have to cool the oil below ignition temperature as it falls through the hole. Not likely, in my opinion. The only way to know for sure is to perform the test. The test is easily performed in a fume hood with tools readily available from a grocery store or kitchen specialty shop. A metal ladle with a metal handle. For some ladles, you will need to bend the handle to make it do this job. I use the largest aluminum foil roasting pan to catch the oil. I use a small aluminum cake pan (inverted) or equivalent to place the cheesecloth on. The height of the ladle above the specimen is critical and must be maintained constant. I use a rest for the ladle handle positioned so that the ladle is at the correct height. The rate of pour is also critical. You will need to practice your timing of the pour to get the rate correct. You'll need someone to help by giving you a countdown as you pour (you can't watch a clock and pour at the same time!). I use putty to make a dam to prevent the oil from going over the edge of the specimen. Put the dam at the edge of the specimen so the oil spreads over the specimen, and does not concentrate at the holes. The oil is standard diesel or household heating oil. You may need a fire extinguisher to extinguish the fire in the roasting pan. The test is flaky, and not super-repeatable. The pass criterion is two passes in succession. (All non-passes are treated as practice tests.) It takes good technique (constant pour rate, and constant height) to get a pass. Best regards, Rich - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Screen Dimensions - Fire Enclosures
John - If you look at the Section after the sentence The following constructions are considered to satisfy the requirement without test: in paragraph 4.4.6. I believe the last item, the metal screen, would be the your simplest solution for the larger vent openings (of course you should use holes lager than .125 with this solution). Or, if you want to get creative, then check out Figure 12, Baffle plate construction. Otherwise, you must have the hot flaming oil test (A5) performed on any perforation not listed on the table. Regards, Mike Campi Corporate Compliance Engineer Fujitsu PC Corporation -Original Message- From: John Juhasz [mailto:jjuh...@fiberoptions.com] Sent: Monday, October 04, 1999 7:39 AM To: 'emc-p...@majordomo.ieee.org' Subject: Screen Dimensions - Fire Enclosures Hi group. With reference to UL 1950 3rd. Ed., Table 15 (size and spacing of holes in metal bottoms of fire enclosures) , I would like some opinions . . . the largest size listed in the table is 1.00mm minimum metal thickness, 2.00mm maxhole dia., and 3.00mm minimum center-center hole spacing. If my metal thickness was greater (1.27mm), and my center-center hole spacing was 4.75mm, could I not go to a larger hole (3.175 - .125)? The reason I pose this question is that the dmensions I was thinking about using are for a 'standard' punch that a sheet metal fabricator would have. UL told me that what's they won't consider it because it's not listed on the chart. I am trying to tell my mechanical designer to use standard perforated stock which falls within the UL guidelines (there is stuff readily available) but he needs more airflow (without fans) . . . Has anyone been there? John Juhasz Fiber Options Bohemia, NY - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Canada Transmitters
Effective May 2000, all transmitters imported into Canada will be checked for Certification. The Certification number will be required on the customs form. A short FAQ sheet is attached and the complete story can be found at http://strategis.ic.gc.ca/SSG/rz00010e.html http://strategis.ic.gc.ca/SSG/rz00010e.html . Here are some of the relative documents which are on line. You can find them using their search engine. RSS-210 Low Power License-Exempt Radiocommunication Devices RSS-212 Test Facilities and Test Methods for Radio Equipment RSP-100 Radio Equipment Certification Procedure TRC-49 Certification Service Fees RR Radiocommunication Regulations RA Radiocommunications Act faq_e.pdf faq_e.pdf Description: Binary data
FW: Coatings for Ferrite Tiles? (Magnetic Wallpaper)
Posted for Eric: :-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 (Voice) 619-505-1502 (Fax) Military Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis :-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) -Original Message- From: eric.lif...@ni.com [SMTP:eric.lif...@ni.com] Sent: Monday, October 04, 1999 8:21 AM To: emc-p...@majordomo.ieee.org Subject: Re: Coatings for Ferrite Tiles? (Magnetic Wallpaper) Our new 3 meter ferrite chamber is lined with white sheet-magnet material, the same stuff used for refrigerator magnets and calendars.. All walls were covered by the installer, but you only really need it around the turntable end. The chamber seems to perform fine with it, but I'd recommend you rerun your -3 field uniformity for the obvious reasons. The best part is -- no glue! If you don't like where it stuck, just pull it off and try again. We kept the shipper/pick-list form and learned that ours came from Master Magnetics, Inc. 108 Industry Road Marietta, Ohio 303-688-3966 The item number and description was ZG2024GW50MG MAG SHEET .020x24x50' GLOSS WHITE. I don't know what the actual cost was, but in quantity it was supposedly less costly than wallpaper, if you can believe that. I suspect that if you searched the web for magnetic sheet you'd find a supplier nearby. Regards, Eric Lifsey Compliance Manager National Instruments - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Coatings for Ferrite Tiles?
Hi Scott, I applied 1 bead board (styrofoam) in 4X8 sheets. After many trials with double sided carpet tape, foam tape, silicone rubber compound (RTV), etc. I found that 'Liquid Nails -Project' (latex based -non solvent) applied with a caulk gun to reliably hold the panels in place. I used a 2 dollop in each corner and one in the center of each panel. This was fairly cheap and quick to apply, but getting 40+ sheets of foam into the back of a pickup and then into the facility (on a breezy Kansas day) quite a challenge. These panels easily break, but patching them isnt too bad if you can catch and retrieve the bits...downwind 1Km. Not only does it aid with the light level, but it also damps the acoustic chatter and just feels warmer.. N'yuck, n'yuck, Kyle -Original Message- From: Lacey,Scott [SMTP:sla...@foxboro.com] Sent: Friday, October 01, 1999 1:26 PM To: 'emc-p...@ieee.org' Subject:Coatings for Ferrite Tiles? To the group, Can anyone recommend a paint or other (light colored) coating that can be applied over ferrite tiles? The lighting in the bat cave (shield room) is rather grim. It can be very difficult to see when working inside of a cabinet. Photos of test setups would also look better if there were less contrast with the background. Scott Lacey - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Screen Dimensions - Fire Enclosures
Hi group. With reference to UL 1950 3rd. Ed., Table 15 (size and spacing of holes in metal bottoms of fire enclosures) , I would like some opinions . . . the largest size listed in the table is 1.00mm minimum metal thickness, 2.00mm maxhole dia., and 3.00mm minimum center-center hole spacing. If my metal thickness was greater (1.27mm), and my center-center hole spacing was 4.75mm, could I not go to a larger hole (3.175 - .125)? The reason I pose this question is that the dmensions I was thinking about using are for a 'standard' punch that a sheet metal fabricator would have. UL told me that what's they won't consider it because it's not listed on the chart. I am trying to tell my mechanical designer to use standard perforated stock which falls within the UL guidelines (there is stuff readily available) but he needs more airflow (without fans) . . . Has anyone been there? John Juhasz Fiber Options Bohemia, NY
EN55011 Class A Group 2 - Resent
(I'm sending this again in TEXT format for those who may have trouble reading RICH TEXT.) Our company makes laboratory equipment so we perform radiated emissions test per EN55011 and apply the CE marking according to EN50081-2 or EN61326-1. Some of our products would fall under the Class A Group 2 category in EN55011, but neither the EN50081-2 or EN61326-1 seem to address this route. At closer look at the EN61326-1 family standard it seems that some of our lab equipment that uses induction heaters and other heating processes might be outside its scope. Is there a different family or generic standard that I should be looking at? Here is my bottom line question. Can I use the Class A Group 2 category? Thanks, Brian Kunde Compliance Testing Center LECO Corp. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Coatings for Ferrite Tiles?
If you use acetone or similar, be careful that it does not leach or get in the tile cracks as it will also eat away the glue on the back of the tiles. Bob Heller === -- Forwarded by Robert E. Heller/US-Corporate/3M/US on 10/04/99 07:35 AM --- JEFF WHITMIRE jeff.whitm...@adtran.com on 10/01/99 05:23:40 PM Please respond to JEFF WHITMIRE jeff.whitm...@adtran.com To: WOODS, RICHARD wo...@sensormatic.com 'emc-p...@ieee.org' emc-p...@ieee.org cc:(bcc: Robert E. Heller/US-Corporate/3M/US) Subject: RE: Coatings for Ferrite Tiles? We have Velcro on the the styrofoam cosmetic panels supplied in our chamber. It works OK if you use lots of Velcro and the tile surface is very clean. I think the chamber vendor used acetone to clean the tile before applying the Velcro strips. Velcro is not really an inexpensive option (go to your local hardware megastore and price a roll). Also, If you have wide variations in temperature and humidity in the chamber, the glue on the Velcro may not hold. -Original Message- From: WOODS, RICHARD [SMTP:wo...@sensormatic.com] Sent: Friday, October 01, 1999 3:05 PM To: 'emc-p...@ieee.org' Subject: RE: Coatings for Ferrite Tiles? We have been considering adding some type of white, light weight, solid covering using Velcro or similar techniques so that the covering is removable. One thought has been ceiling tiles. Any suggestions? -- From: Lacey,Scott [SMTP:sla...@foxboro.com] Sent: Friday, October 01, 1999 2:26 PM To: 'emc-p...@ieee.org' Subject: Coatings for Ferrite Tiles? To the group, Can anyone recommend a paint or other (light colored) coating that can be applied over ferrite tiles? The lighting in the bat cave (shield room) is rather grim. It can be very difficult to see when working inside of a cabinet. Photos of test setups would also look better if there were less contrast with the background. Scott Lacey - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Coatings for Ferrite Tiles?
We used a wall paper recommended by the manufacturer of the ferrite tile. I could dig our the type/brand name if you are interested. It has been up for over two years without any signs of wear. We did site attenuation before and after with no noticeable affect. I'd recommend you do the same no matter what you use. Bob Heller = Lacey,Scott sla...@foxboro.com on 10/01/99 01:25:45 PM Please respond to Lacey,Scott sla...@foxboro.com To: 'emc-p...@ieee.org' emc-p...@ieee.org cc:(bcc: Robert E. Heller/US-Corporate/3M/US) Subject: Coatings for Ferrite Tiles? To the group, Can anyone recommend a paint or other (light colored) coating that can be applied over ferrite tiles? The lighting in the bat cave (shield room) is rather grim. It can be very difficult to see when working inside of a cabinet. Photos of test setups would also look better if there were less contrast with the background. Scott Lacey - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Warning label sizing.
EN60825-1 and IEC 825-1 do not specify a minimum size but they do state that the warning must be legible and clearly visible. This might help you... they state If the size or design of the product makes labelling impractical, the label should be included with the user information or on the package. Chris Colgan EMC Safety TAG McLaren Audio Ltd mailto:chris.col...@tagmclarenaudio.com -Original Message- From: Ehler, Kyle [SMTP:kyle.eh...@lsil.com] Sent: 01 October 1999 19:34 To: EMC and Safety list Subject: Warning label sizing. Greetings, We have been lucky in the past, but with the real estate crunch that comes with smaller products, its getting more difficult to find space to apply a warning label. For example, a 'Class 1 Laser Product'. Just how tiny can the text/graphics in a label be and still comply? Kyle - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). = Authorised on 10/04/99 at 12:51:38; code 37f48bf367EB75CF. The contents of this E-mail are confidential and for the exclusive use of the intended recipient. If you receive this E-mail in error, please delete it from your system immediately and notify us either by E-mail, telephone or fax. You should not copy, forward or otherwise disclose the content of the E-mail. TAG McLaren Audio Ltd, The Summit, 11 Latham Road Huntingdon, Cambs, PE18 6ZU Telephone : 01480 415600 (+44 1480 415600) Facsimile : 01480 52159 (+44 1480 52159) - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: EN55011 Class A Group 2
Brian, I was waiting to see if someone more experienced in EN 55011 answered, but seeing none yet, here's my comment. If your equipment falls under the scope of EN 55011 industrial, scientific and medical (ISM) radio-frequency equipment then why not use this standard directly as the harmonised standard by which you declare your product compliant with the emissions aspects of the EMC Directive? Then you can use any applicable category from that standard. Roger Brian At Work bkundew...@qtm.net on 30/09/99 14:26:52 Please respond to Brian At Work bkundew...@qtm.net To: IEEE Group emc-p...@ieee.org cc:(bcc: Roger Viles/PLY/Global) Subject: EN55011 Class A Group 2 Our company makes laboratory equipment so we perform radiated emissions test per EN55011 and apply the CE marking according to EN50081-2 or EN61326-1. Some of our products would fall under the Class A Group 2 category in EN55011, but neither the EN50081-2 or EN61326-1 seem to address this route. At closer look at the EN61326-1 family standard it seems that some of our lab equipment that uses induction heaters and other heating processes might be outside its scope. Is there a different family or generic standard that I should be looking at? Here is my bottom line question. Can I use the Class A Group 2 category? Our company makes laboratory equipment so we perform radiated emissions test per EN55011 and apply the CE marking according to EN50081-2 or EN61326-1. Some of our products would fall under the Class A Group 2 category in EN55011, but neither the EN50081-2 or EN61326-1 seem to address this route. At closer look at the EN61326-1 family standard it seems that some of our lab equipment that uses induction heaters and other heating processes might be outside its scope. Is there a different family or generic standard that I should be looking at? Here is my bottom line question. Can I use the Class A Group 2 category?
Re: Warning label sizing.
Kyle and Tin Bear, The Class 1 Laser Product is a European requirement (see EN 60 825) and the marking does not have to be on the product; For Class 1 only, marking may be in the User Manual. Reagards, At 16:43 01/10/99 EDT, tinb...@aol.com wrote: Kyle, My response would be .08 inch minimum type size for the letter height in the laser label. per the Informative Annex B of ANSI Z535.4. RATIONALE/BASIS: Section 4.7.1 of the American National Standard Z136.1-1993, Safe Use of Lasers states Design of Signs. Sign dimensions, letter size and color, etc., shall be in accordance with American National Standard Specification for Accident Prevention Signs, ANSI Z535 Series (latest revision thereof). Figures 1a and 1b show sample signs for Class 2, Class 3a, Class 3b and Class 4 laser or laser systems. ANSI Z535.4-1998 Product Safety Signs and Labels has a section in Informative Annex B.3.2.13 addressing 'minimum letter height calculations'. B3.2.13 Minimum letter height calculations. Type size is defined in points, a term that was used to describe the space required for lead type characters. Point sizes measure from the top of the capital letters to the bottom of the lower case letters with descenders (e.g., the bottom of the letter g or j etc.). One point equals 0.01384 inches, or approximately 1/72 of an inch. Although type faces vary slightly, a practical guide for defining type size is based on using the capital letter H for measurement purposes. Since the character H has no descender, it is possible to use a conversion factor of 0.01 inches - 1 point of type size. Thus, 12 point type yields a capital H approximately 0.12 inches high. For metric purposes, use a conversion factor of 3.9 points = 1 mm of height for a capital H. Recommended Letter Heights For Favorable Reading Conditions: 2 Feet or Less: Viewing Distance (in.)/150 2 To 20 Feet: Viewing Distance ((ft.-2) X (.03)) +.16 Over 20 Feet: Viewing Distance (ft.)/28.6 Recommended Letter Heights For Unfavorable Reading Conditions (All Distances): Viewing Distance (ft.)X 0.84 Table - Examples of word message letter heights and minimum safe viewing distances. (Note: Only the first row is reflected below). Minimum Safe Viewing Distance - 1 Foot or less Minimum Letter Height for Favorable Reading Conditions - .08 inches Recommended Letter Height for Favorable Reading Conditions - .08 inches Recommended Letter Height for Unfavorable Reading Conditions - .084 inches (Note: Only the first row is reflected above). *.08 inch type is the suggested minimum type size for use on product safety signs. Regards. Tin In a message dated 10/1/99 11:43:04 AM Pacific Daylight Time, kyle.eh...@lsil.com writes: Greetings, We have been lucky in the past, but with the real estate crunch that comes with smaller products, its getting more difficult to find space to apply a warning label. For example, a 'Class 1 Laser Product'. Just how tiny can the text/graphics in a label be and still comply? Kyle - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). Peter Merguerian Managing Director Product Testing Division I.T.L. (Product Testing) Ltd. Hacharoshet 26, POB 211 Or Yehuda 60251, Israel Tel: 972-3-5339022 Fax: 972-3-5339019 e-mail: pmerguer...@itl.co.il website: http://www.itl.co.il THE UL 1950 SEMINAR: 12-13th October 1999 Check it out! http://www.itl.co.il/seminar.htm - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Magnetic Field Testing
Hi Ed At our laboratory we do some tests according to IEC 60945 (equipment for ships) and one of the test are a Compass Safe Distance Test. IEC 60945 specifies a deviation angle of 5.4 degrees when the horizontal field is only 1 micro Tesla (close to the poles of the earth). The deviation in compass direction depends of the place of test on the earth. In Denmark the vertical field is 46 micro Tesla and the horizontal field is 17 micro Tesla so this deviation angle becomes only 0.3 degrees in Denmark. We do such test by placing a sensitive one direction magnetometer on a wooden table and fix it in the east-west direction at zero field deflection. Then we move the test object towards the sensor and look at the deflection in field. (Remove the keys from your pockets before doing this test. Any moving iron parts nearby disturbs the test). IEC 60945 do also specify a way of magnetizing a test object. It says: 80 A/m DC + 1430 A/m AC, 50Hz. The AC-field provides a stabilization of the field. When you expose some steel to 80 A/m DC only, you get almost no remanent magnetisation. When you add the AC field and then remove the field (as when you demagnetize something) then you get a remanent field from the test object with some steel in it. Hopefully you can use some of this information. Best regards Viggo Brøndegaard DELTA Electronics testing Price, Ed ed.pr...@cubic.com 30-09-99 18.49 Hi Listmembers: Today's weird science question is about sensing the strength of a permanent magnetic field. I need to expose an electronics box to a strong magnetic field (10 Gauss). Then, after removing the field, I need to approach the box with a compass and note the separation distance needed to deflect the compass needle a couple of degrees. A couple of degrees is pretty hard to read, even on a large compass! The purpose of the test is to make sure that objects exposed to temporary magnetic fields do not retain enough field to disrupt a nearby magnetic compass. I am trying to determine what kind of sensor I can use. I have been looking at electronic compass modules. Some models provide a DC analog output voltage proportional to angle or heading. Has anyone tried this method? Are the modules stable enough for this to work? Is there a big problem with the placement of the data output lines? Thanks, Ed :-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 (Voice) 619-505-1502 (Fax) Military Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis :-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
