FW: Doubt on household equipment interference
-Original Message- From: Pettit, Ghery Sent: Wednesday, September 01, 1999 2:55 PM To: 'Muriel Bittencourt de Liz'; 'emc-p...@ieee.org' Subject: RE: Doubt on household equipment interference Muriel, I would expect to see interference in this case, as well. The neutral is common and there will be significant crosstalk in the 3 phase wiring, allowing RF from the blender to couple to the phase feeding the TV. Murphy is alive and well. Ghery Pettit Intel -Original Message- From: Muriel Bittencourt de Liz [SMTP:mur...@grucad.ufsc.br] Sent: Wednesday, September 01, 1999 12:55 PM To: Lista de EMC da IEEE Subject: Doubt on household equipment interference Dear Members I'd like to solve a doubt.. suppose the following: I have an electrical installation in a house. The feeding is with three-phase and one neutral conductors. If I connect a TV and a blender in the same phase, the blender generates interference (lines) in the TV screen. If I connect the TV in one phase, and the blender in another, the TV will have interference??? The neutral conductor is the same for all (of course!) Seems very plain, but I'd like to know... :) Thanks in advance Muriel -- == Muriel Bittencourt de Liz GRUCAD - Conception Analysis of Electromagnetic Devices Group Federal University of Santa Catarina PO Box: 476 ZIP: 88040-900 - Florianópolis - SC - BRAZIL Phone: +55.48.331.9649 - Fax: +55.48.234.3790 e-mail: mur...@grucad.ufsc.br ICQ#: 9089332 - 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).
Doubt on household equipment interference
Dear Members I'd like to solve a doubt.. suppose the following: I have an electrical installation in a house. The feeding is with three-phase and one neutral conductors. If I connect a TV and a blender in the same phase, the blender generates interference (lines) in the TV screen. If I connect the TV in one phase, and the blender in another, the TV will have interference??? The neutral conductor is the same for all (of course!) Seems very plain, but I'd like to know... :) Thanks in advance Muriel -- == Muriel Bittencourt de Liz GRUCAD - Conception Analysis of Electromagnetic Devices Group Federal University of Santa Catarina PO Box: 476 ZIP: 88040-900 - Florianópolis - SC - BRAZIL Phone: +55.48.331.9649 - Fax: +55.48.234.3790 e-mail: mur...@grucad.ufsc.br ICQ#: 9089332 - 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).
Pressure Equipment Directive Analysis file
Trying to be helpful, and I create more trouble...oh well... some people were not able to open the Word document I attached to a previous message. It was created under windows 95 Word 7.0 SR1. Here is the same document saved as RTF. Hope this helps. -Lauren Crane PED analysis.rtf PED analysis.rtf Description: RTF file
Re: Pressure Equipment Directive
On Wed, 1 Sep 1999, Crane, Lauren wrote: == In reading through the PED (97/23/EC) I notice the following, apparent contradiction... The text of say Article 3, section 1.1(a) first indent says for fluids in Group 1 with a volume greater than 1 L and a product of PS and V greater than 25 bar 7L, or with a pressure PS greater than 200 bar (Annex II, table 1), The confusing bit is the '7L' in '25 bar 7L'. When I look at the graph of table 1 it looks like the limit is the product of pressure and volume exceeding 25 bar * 1L. What is that 7 (seven) all about? Any ideas??? Dear Lauren: That is a translation error between different character sets used to display on computers. The correct interpretation is to determine the product of pressure (in bars) time the volume (in liters). I have studied the Pressure Equipment Directive tables in Annex II and created a matrix to guide me in the analysis of our equipment. This matrix may be useful to others, so I have attached it. It seems that the only elements of our equipment that cause us to fall within the constrained scope of the directive are the gas bottles that are installed by the user and not supplied by us. Removing these bottles from consideration, our equipment would not fall into even the first Category of any of the 9 tables, and so we would be obligated by only Article 3, section 3. It seems to me that since we do not supply the gas bottles with our equipment, we may take this approach, and avoid all of the conformity assessment procedures called out in article 10 section 1.3. I look forward to any comments on this opinion. I have yet to look at your analysis, but must say that I appreciate your attaching it and making it available. It is my opinion that in general, a manufacturer of something that is to be evaluated under the Machinery (or Low Voltage) Directive is not likely to be called to perform an evaluation to the Pressure Equipment Directive. This is because the area under Category I covers the bulk of pneumatic and hydraulic systems. Regards, Chuck Seyboldt - 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).
FW: NFPA and overcurrent protection requirements.
Posted for chuck_me...@electro-test.com: :-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) 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: Chuck Mello [SMTP:chuck_me...@electro-test.com] Sent: Wednesday, September 01, 1999 7:41 AM To: s...@world.std.com; 'emc-p...@majordomo.ieee.org'; 'n...@nfpa.org' Subject: Re: NFPA and overcurrent protection requirements. Lauren The NEC and NFPA 79 are pretty much in alignment with each other for overcurrent protection of conductors. The basic rule as you properly stated is that overcurrent protection is to be provided at the source or the start of the conductors being protected. For the situation posed by the exceptions to paragraph 8.4 and also by NEC Section 240-21 for tapped conductors, you have to consider the elements of overcurrent protection separately to understand the application. Overcurrent protection includes short circuit, ground fault and overload as the three elements. What the exceptions and the NEC tap rules do is allow you to have only the short circuit and ground fault protection ahead of the conductors as provided by the main or feeder device. That is where the requirements of the tap conductor having an ampacity of not less than 10 times the feeder conductor for the 10 foot rule or the tap has to be at least 1/3 the ampacity of the main conductors in the 25 foot limitations. The overload protection is then provided by a limited load and within the enclosure (10 foot rule) or a device (circuit breaker or single set of fuses) at the load end of the conductors (10 and 25 foot rules). The position of the overload device in the circuit is not as critical in that it provides protection ahead of and below the device for the conductors. Another example of this that is similar is motor protection where the short circuit device is at the source of the circuit, and the controller with the overload device is possibly at some distance away toward the motor. All the branch circuit conductors from the short circuit device to the motor are protected by the overload device no matter where it is located in the circuit. Joe Sheehan at NFPA is the staff liaison for NFPA 79 and is an excellent practical resource. NFPA policy is that staff can provide an opinion but formal interpretations have to go through the technical committees which can take some time. -- From: Crane, Lauren lcr...@bev.etn.com To: 's...@world.std.com'; 'emc-p...@majordomo.ieee.org'; 'n...@nfpa.org' Subject: NFPA and overcurrent protection requirements. Date: Monday, August 30, 1999 9:19 AM Dear Colleagues, NFPA 79 (1997) provides the following requirement regarding overcurrent protective devices... 8.4 Overcurrent protective devices shall be located at the point where the conductor to be protected receives its supply. Then two exceptions are provided. However, it is not explicit if the exception is regarding the placement of the protective device at the supply point to the conductor, or is the exception regarding the provision of the protective device. In other words, does the exception allow the protective device to be absent under the given conditions? A similar section in EN 60204 (1997) is 7.2.8 An overcurrent protective device shall be located at the point where the conductor to be protected is connected to its supply. Where that is not possible, no overcurrent protection is required for those conductors with current-carrying capacity less than that of the supply conductors, provided that the possibility of a short circuit is reduced by all of the following measures:... This section clearly states that the exception allows not having any protection at all. It seems reasonable that the intent of NFPA 79 is the same as EN 60204 .. but I want to be a bit more certain. So...the basic questionIF all the conditions are met for either the first or second exception of section 8.4 in NFPA 79, may an overcurrent protective device be left out? And two follow-ups ...with regard to exception 1, the last condition the conductor terminates in a single circuit breaker or set of fuses means, for example, a 16 awg wire may get its supply from a terminal block fed by a 2 awg wire, but it must terminate at the other end in a circuit breaker or fuse sized correctly for the 16 awg wire. Is this correct? ...with regard to exception 2, the last condition the conductor terminates in a splitter block, circuit breaker or set of fuses. This means that the 16 awg wire of the
RE: hard anodized process to insulate metal chassis parts
Yes we hit this problem several years ago, hence my qualifier of non-hydroscopic of which there are various options -Original Message- From: Linstrom, John (IndSys, GEFanuc, CDI) [mailto:john.linst...@gefgreenville.ge.com] Sent: Wednesday, September 01, 1999 3:20 PM To: 'James, Chris' Cc: 'emc-p...@ieee.org' Subject: RE: hard anodized process to insulate metal chassis parts Maybe a slip of the fingers... We recently got bit on the fishpaper insulation. Fishpaper absorbs moisture; better to call it plastic, or mylar, etc. than to leave a possible suggestion that fishpaper is any good for this application. John Linstrom Computer Dynamics PH 864.281.7768 x266 FX 864.675.0106 john.linst...@cdynamics.com -Original Message- From: James, Chris [ mailto:c...@dolby.co.uk mailto:c...@dolby.co.uk ] Sent: Wednesday, September 01, 1999 3:16 AM To: Subject: RE: hard anodized process to insulate metal chassis parts Given that sulphuric hard III anodizing is only .001 to .003 thick then I'd have thought not. It is also fairly easy to compromise, so in a mechanical assembly you would be hard pressed to know how good the insulator was or how long it would remain so after the rigours of use (vibration etc.). Better to stick with SIL pad type materials or non-hydroscopic Fish card type insulators. Chris James -Original Message- From: Paul J Smith [ mailto:paul_j_sm...@notes.teradyne.com mailto:paul_j_sm...@notes.teradyne.com ] Sent: Tuesday, August 31, 1999 6:20 PM To: emc-p...@ieee.org Subject: hard anodized process to insulate metal chassis parts Good afternoon, Does anyone know of a process of Hard Anodized metal chassis parts that is considered an acceptable insulator against hazardous voltages by any agency. The related spec describing this process is MIL- A-8625F. Please advise at your earliest convenience. Thanks Best Regards, Paul J Smith Teradyne, Inc., Boston paul.j.sm...@teradyne.com Voice 617-422-2997 FAX 603-843-7526 - 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).
FW: hard anodized process to insulate metal chassis parts
Posted for john.linst...@cdynamics.com :-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) 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: Linstrom, John (IndSys, GEFanuc, CDI) [SMTP:john.linst...@gefgreenville.ge.com] Sent: Wednesday, September 01, 1999 7:20 AM To: 'James, Chris' Cc: 'emc-p...@ieee.org' Subject: RE: hard anodized process to insulate metal chassis parts Maybe a slip of the fingers... We recently got bit on the fishpaper insulation. Fishpaper absorbs moisture; better to call it plastic, or mylar, etc. than to leave a possible suggestion that fishpaper is any good for this application. John Linstrom Computer Dynamics PH 864.281.7768 x266 FX 864.675.0106 john.linst...@cdynamics.com -Original Message- From: James, Chris [ mailto:c...@dolby.co.uk] Sent: Wednesday, September 01, 1999 3:16 AM To: Subject: RE: hard anodized process to insulate metal chassis parts Given that sulphuric hard III anodizing is only .001 to .003 thick then I'd have thought not. It is also fairly easy to compromise, so in a mechanical assembly you would be hard pressed to know how good the insulator was or how long it would remain so after the rigours of use (vibration etc.). Better to stick with SIL pad type materials or non-hydroscopic Fish card type insulators. Chris James -Original Message- From: Paul J Smith [ mailto:paul_j_sm...@notes.teradyne.com] Sent: Tuesday, August 31, 1999 6:20 PM To: emc-p...@ieee.org Subject: hard anodized process to insulate metal chassis parts Good afternoon, Does anyone know of a process of Hard Anodized metal chassis parts that is considered an acceptable insulator against hazardous voltages by any agency. The related spec describing this process is MIL- A-8625F. Please advise at your earliest convenience. Thanks Best Regards, Paul J Smith Teradyne, Inc., Boston paul.j.sm...@teradyne.com Voice 617-422-2997 FAX 603-843-7526 - 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: Hard Anodised Process to insulate metal parts
I had the opposite problem once, of ensuring electrical connection to an anodised aluminium part, for shielding purposes. The only sure way was to machine away the anodising on the surface where contact was to be made. But that is quite different from relying on the anodising for insulation, which I would not have thought a good idea. One scratch, and there is a path through the conversion coating. Best regards, Jeff Chambers - Dr Jeff Chambers Westbay Technology Ltd Suppliers of EMC Design Software Tel: +44 1229 869 108 Fax: +44 1229 869 108 http://www.westbay.ndirect.co.uk/westbay1.htm j.chamb...@ndirect.co.uk Main St Baycliff Ulverston Cumbria LA12 9RN England - - 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).
EMC Test Houses in Naples
Could anyone please provide me with the name and contact information for any EMC testing facility in or near Naples, Italy. Thanks, Bob Heller Sr. EMC Engineer 3M Company - 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).
Pressure Equipment Directive
Dear Colleagues, Two items regarding this. == In reading through the PED (97/23/EC) I notice the following, apparent contradiction... The text of say Article 3, section 1.1(a) first indent says for fluids in Group 1 with a volume greater than 1 L and a product of PS and V greater than 25 bar 7L, or with a pressure PS greater than 200 bar (Annex II, table 1), The confusing bit is the '7L' in '25 bar 7L'. When I look at the graph of table 1 it looks like the limit is the product of pressure and volume exceeding 25 bar * 1L. What is that 7 (seven) all about? It looks like it could be a typo that has crept in. I appears consistently in the text. It shows up in the directive posted in the Commission web site and at a site maintained by Finland. If the seven is taken as written then the limit in my example is 25*7 or 175. But this conflicts with the table 1 graph indicating a limit line of PS * V = 25. Any ideas??? = I have studied the Pressure Equipment Directive tables in Annex II and created a matrix to guide me in the analysis of our equipment. This matrix may be useful to others, so I have attached it. It seems that the only elements of our equipment that cause us to fall within the constrained scope of the directive are the gas bottles that are installed by the user and not supplied by us. Removing these bottles from consideration, our equipment would not fall into even the first Category of any of the 9 tables, and so we would be obligated by only Article 3, section 3. It seems to me that since we do not supply the gas bottles with our equipment, we may take this approach, and avoid all of the conformity assessment procedures called out in article 10 section 1.3. I look forward to any comments on this opinion. PED analysis.doc Best Regards, Lauren Crane Senior Safety and Compliance Engineer Eaton Corporation PED analysis.doc Description: MS-Word document
RE: US Circuit breaker requirements
Paul, I believe the requirement is related to flammable liquids such as gasoline and LP gas. For example in gas stations electrical components are typically installed at least 18 above the ground. Additionally, my hot water heater at home is on an 18 stand. The NEC covers some of the requirements in Art. 500 through 555. Best Regards, Jody Leber jle...@ustech-lab.com http://www.ustech-lab.com U. S. Technologies 3505 Francis Circle Alpharetta, GA 30004 770.740.0717 Fax: 770.740.1508 -Original Message- From: Paul Smith [SMTP:phsm...@excite.co.uk] Sent: Tuesday, August 31, 1999 8:56 AM To: emc-p...@majordomo.ieee.org Subject:US Circuit breaker requirements Could somebody dispel an 'urban myth' for me. UL 891 states that circuit breakers in Dead Front Switchboards shall be placed no higher than 6 1/2 foot (2 metres) from the base of the rack they are installed in. Thats fine and I can find the references fine in the UL specification. But, I am told that they can be placed no lower than 6 inches (or possibly even 18 inches) above the base of the rack they are installed in. This is the 'myth' I need some information on. I've read UL 891 but haven't found any reference to this matter in it (or if I did my brain was switched off at that point). What is the requirement for the minimum mounting height for circuit breakers in Dead Front Switchboards? Is it covered by UL891, or is it hiding in the NEC regulations? Any ideas? Paul Excite -- Control Yourself. This E-mail brought to you by Excite's free E-mail service. Get your own E-mail address at http://www.excite.co.uk - 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: FCC 47 CFR Part 18
Jeff This section of FCC rules, which have the force of law, is for ISM - Industrial Scientific and Medical - devices that use RF energy for non-communications uses, such as generating heat (ex. microwave oven), light (ex RF excited flourescent lights) or generating plasma (ex: semiconductor wafer process chambers). For non-residential products no FCC submission is required but you must meet radiated and/or AC conducted limits in rules to show compliance with FCC Part 18. best regards Tom Cokenias T.N. Cokenias Consulting P.O. Box 1086 El Granada CA 94018 tel 650 726 1263fax 650 726 1252 At 12:37 PM -0600 8/31/99, JENKINS, JEFF wrote: Does anyone know if there are laws that require semiconductor processing equipment and other types of industrial equipment to conform to FCC 47 CFR Part 18? From time to time we get inquiries about this and we're wondering what is behind it. Thanks, Jeff Jenkins Advanced Energy Industries, Inc. - 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: hard anodized process to insulate metal chassis parts
Given that sulphuric hard III anodizing is only .001 to .003 thick then I'd have thought not. It is also fairly easy to compromise, so in a mechanical assembly you would be hard pressed to know how good the insulator was or how long it would remain so after the rigours of use (vibration etc.). Better to stick with SIL pad type materials or non-hydroscopic Fish card type insulators. Chris James -Original Message- From: Paul J Smith [mailto:paul_j_sm...@notes.teradyne.com] Sent: Tuesday, August 31, 1999 6:20 PM To: emc-p...@ieee.org Subject: hard anodized process to insulate metal chassis parts Good afternoon, Does anyone know of a process of Hard Anodized metal chassis parts that is considered an acceptable insulator against hazardous voltages by any agency. The related spec describing this process is MIL- A-8625F. Please advise at your earliest convenience. Thanks Best Regards, Paul J Smith Teradyne, Inc., Boston paul.j.sm...@teradyne.com Voice 617-422-2997 FAX 603-843-7526 - 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: OATS Rework Results
Don , Please allow me to input a wild speculation. Given: Everything is OK with your OATS, Antennas, measurements and calculations. What's wrong with 30 MHz in Vertical? My suspicion is that the antenna was not properly calibrated in V (Vertical). Antennas were usually calibrated in accordance with ANSI C63.5, which only asks for calibration in H (Horizontal), and then assume AFv = AFh. As a matter of fact, the AFv is somewhat different from AFh. People would argue why other OATS validations don't have the same problem. My defense is that when applying AFh to the V measurement the induced error is only 1 to 2 dB. That's why some are still within the allowance of +/-4 dB, and some would go out. ... It will be interesting to analyze all data in V at 30 MHz from a variety of OATS validation across the world to see if they have a systematic deviation .. Barry Ma b...@anritsu.com -- Original Text -- From: UMBDENSTOCK, DON umbdenst...@sensormatic.com, on 8/30/99 3:11 PM: Hello Group, I would like to report on the results of implementing the recommendations offered by many. We found the wire cloth to be rusty where clamped between the stainless steel ring and the concrete pad. This no doubt contributed to the 40 ohm impedance. We replaced a 3 m square of wirecloth surrounding the 1.5 meter turn-table. We did the acid wash, air blown joint technique. (The air was more necessary to remove the excess moisture.) With a 1.5 inch tip 500 W iron, the soldering was quick (.093 60/40 resin core solder was readily available). We connected the wire cloth to the ss turn-table ring by means of 5/8 wide tinned copper braid soldered on the ss and on the wirecloth. (One of our techs found a company that makes flux for ss. It was as simple soldering to ss as soldering to copper.) We strapped the wire cloth to the ss ring with 2 long segments every 3 apart. We now have .5 ohm (dc) impedance from the turn-table to the wirecloth pad. Our 3 meter measurement is uniform over the 14m x 15 m pad within .8 dB (.8 dB from highest to lowest reading). Unfortunately, the noncompliance at 30 MHz in vertical polarization is still there. Using the formula for a 3 meter site of NSA=Vd-Vs-Raf-Taf-Cf where Vd = V direct, Vs = V site Raf = Rx ant factor Taf = Tx ant factor Cf = mutual coupling factor Vs appears to be too high by .5-1.5 dB, and about 1.5 - 2.5 dB higher than previous NSA measurements. Whether the ground was wet or dry, we have gotten comparable results. Anyone have any good ideas? Still stymied, Don Umbdenstock Sensormatic - 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).
USB Shield Grounding
A question regarding the Universal Serial Bus (USB) Specification. USB spec. 1.0 required the cable shield at the peripheral end to be DC isolated from the chassis; ie, it could be terminated only through a capacitor(s). That requirement always seemed strange for a cable with a max. length of 5 meters. And it has caused us some trouble with EMI. Now, if I'm reading it correctly, USB 1.1 has quietly removed that restriction and allows the shield to be grounded to the chassis at both ends (as it should have been from the start!). Is this correct? Thanks, Jack Cook, EMC Engineer, Xerox Corp. jack.c...@cax.usa.xerox.com - 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: FCC 47 CFR Part 18
At 12:37 PM 8/31/99 -0600, JENKINS, JEFF wrote: Does anyone know if there are laws that require semiconductor processing equipment and other types of industrial equipment to conform to FCC 47 CFR Part 18? From time to time we get inquiries about this and we're wondering what is behind it. Thanks, Jeff Jenkins Advanced Energy Industries, Inc. Jeff, Go to http://www.access.gpo.gov/nara/cfr/ The correct title of what you're asking is CFR Title 47, Part 18. CFR is an acronym for Code of Federal Regulations. In other words, it IS Federal law. And if your equipment correlates to any of the criteria contained therein, then ye shall test. Regards, Doug - 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).
