FW: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS
This is a multi-part message in MIME format. Failed to attach the file. jgs Jim Sketoe M/C S106-3050 (314)232-4782 (Voice) (314)232-7391 (Fax) From: Gordon,Ian [mailto:ian.gor...@edwards.boc.com] Sent: Thursday, January 23, 2003 9:15 AM To: 'IEEE EMC-PSTC GROUP' Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS All I would like to construct a Helmholtz coil to perform magnetic field immunity testing at DC frequencies and thus simulate the effect of a permanent magnet. There are some details on construction in EN61000-4-8 which details power frequency magnetic field immunity testing within the scope of the EMC directive. However the fields referred to are measured in A/m, whereas I need a field of, for example, 5mTesla. Can anybody advise me as to how to construct such a coil with a test volume of 0.5 x 0.5 x 0.5m and a field of 5mTesla? Thanks Ian Gordon _ This e-mail has been scanned for viruses by the WorldCom Internet Managed Scanning Service - powered by MessageLabs. For further information visit http://www.worldcom.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list Title: FW: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS Failed to attach the file. jgs Jim Sketoe M/C S106-3050 (314)232-4782 (Voice) (314)232-7391 (Fax) -Original Message- From: Gordon,Ian [mailto:ian.gor...@edwards.boc.com] Sent: Thursday, January 23, 2003 9:15 AM To: 'IEEE EMC-PSTC GROUP' Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS All I would like to construct a Helmholtz coil to perform magnetic field immunity testing at DC frequencies and thus simulate the effect of a permanent magnet. There are some details on construction in EN61000-4-8 which details power frequency magnetic field immunity testing within the scope of the EMC directive. However the fields referred to are measured in A/m, whereas I need a field of, for example, 5mTesla. Can anybody advise me as to how to construct such a coil with a test volume of 0.5 x 0.5 x 0.5m and a field of 5mTesla? Thanks Ian Gordon _ This e-mail has been scanned for viruses by the WorldCom Internet Managed Scanning Service - powered by MessageLabs. For further information visit http://www.worldcom.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list RUBENS.DOC Description: Binary data
FW: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS
This sounds much like what I call Rubens Coil. The attached Word doc describes the unit. Mr. Rubens deserves the credit. jgs Jim Sketoe M/C S106-3050 (314)232-4782 (Voice) (314)232-7391 (Fax) From: Gordon,Ian [mailto:ian.gor...@edwards.boc.com] Sent: Thursday, January 23, 2003 9:15 AM To: 'IEEE EMC-PSTC GROUP' Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS All I would like to construct a Helmholtz coil to perform magnetic field immunity testing at DC frequencies and thus simulate the effect of a permanent magnet. There are some details on construction in EN61000-4-8 which details power frequency magnetic field immunity testing within the scope of the EMC directive. However the fields referred to are measured in A/m, whereas I need a field of, for example, 5mTesla. Can anybody advise me as to how to construct such a coil with a test volume of 0.5 x 0.5 x 0.5m and a field of 5mTesla? Thanks Ian Gordon _ This e-mail has been scanned for viruses by the WorldCom Internet Managed Scanning Service - powered by MessageLabs. For further information visit http://www.worldcom.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS
The relationship between Amps per meter and Teslas is easily derived from the basic relationship: B = uH, where B is magnetic induction in Teslas or Webers per square meter, u = permeability of material which has units of Henries per meter, H = magnetic field, with units of Amperes per meter. From: Gordon,Ian ian.gor...@edwards.boc.com To: 'IEEE EMC-PSTC GROUP' emc-p...@majordomo.ieee.org Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS Date: Thu, Jan 23, 2003, 9:15 AM All I would like to construct a Helmholtz coil to perform magnetic field immunity testing at DC frequencies and thus simulate the effect of a permanent magnet. There are some details on construction in EN61000-4-8 which details power frequency magnetic field immunity testing within the scope of the EMC directive. However the fields referred to are measured in A/m, whereas I need a field of, for example, 5mTesla. Can anybody advise me as to how to construct such a coil with a test volume of 0.5 x 0.5 x 0.5m and a field of 5mTesla? Thanks Ian Gordon _ This e-mail has been scanned for viruses by the WorldCom Internet Managed Scanning Service - powered by MessageLabs. For further information visit http://www.worldcom.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS
-Original Message- From: Gordon,Ian [mailto:ian.gor...@edwards.boc.com] Sent: Thursday, January 23, 2003 7:15 AM To: 'IEEE EMC-PSTC GROUP' Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS All I would like to construct a Helmholtz coil to perform magnetic field immunity testing at DC frequencies and thus simulate the effect of a permanent magnet. There are some details on construction in EN61000-4-8 which details power frequency magnetic field immunity testing within the scope of the EMC directive. However the fields referred to are measured in A/m, whereas I need a field of, for example, 5mTesla. Can anybody advise me as to how to construct such a coil with a test volume of 0.5 x 0.5 x 0.5m and a field of 5mTesla? Thanks Ian Gordon OK, less drama and more numbers. In a Helmholtz, the sweet spot or volume, should be limited to 1/3 the distance between the coils. So that means that coil separation should be 150cm to yield a test volume of 50cm. And, the definition of a Helmholtz is two identical flat coils, in plane, and separated by the radius of the coil. So, the radius of the coil is also 150cm. Now, the Helmholtz equation, re-arranged to find necessary current when the field (Gauss), turns (N), radius (a, in cm) and separation (cm) are known. I= [((5)^^(1.5)) x a x 10 x Gauss] / [ 32 x Pi x N ] So, lets try with a 150 cm radius separation coil, with 50 turns, looking for 50 Gauss (which is equivalent to your 5 milliTeslas). I = [((5)^^(1.5) x 150 x 10 x 50] / [ 32 x Pi x 50] (please don't let me mess this up) I = 838526 / 5026 = 167 Amps The only variables you can work with are number of turns and current. What size power supply have you got? Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS
Gordon, the May 2002 issue of Conformity magazine had an excellent article on Helmholtz coils. I checked their website but didn't see how to access old issues. If you can't get a copy online I will be glad to FAX you a copy of the article. To put things in perspective we can think about the field around an infinite length wire. Say the wire has a current of 1 ampere and the point of measurement is 1 meter away. The field H is (1A)/(2Pi meters)= 0.16 A/m. Now B=uH and u = 1.256uH/m. So, B= (1.256uH)(0.16A/m) = 200nT. To obtain 5mT one would need 25,000 amps with this arrangement! Let's do a Helmholtz: H = 1.43(nI/d) where d is the diameter of the circular coil. The coils are spaced one diameter. For coils with a diameter of 1 meter, one turn, and one ampere the field H is 1.43 A/m. You need about 4000 A/m for 5mT. Lots of amps. How about 200 turns at 20 amps? That will do it. So, two 1-meter coils with 200 turns of #12 AWG wire with 20 amps flowing. The resistance at 100 deg C is about 10 ohms, so 200 VDC is needed. 2000 watts. Smokin!! Dave Cuthbert Micron Technology From: Gordon,Ian [mailto:ian.gor...@edwards.boc.com] Sent: Thursday, January 23, 2003 8:15 AM To: 'IEEE EMC-PSTC GROUP' Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS All I would like to construct a Helmholtz coil to perform magnetic field immunity testing at DC frequencies and thus simulate the effect of a permanent magnet. There are some details on construction in EN61000-4-8 which details power frequency magnetic field immunity testing within the scope of the EMC directive. However the fields referred to are measured in A/m, whereas I need a field of, for example, 5mTesla. Can anybody advise me as to how to construct such a coil with a test volume of 0.5 x 0.5 x 0.5m and a field of 5mTesla? Thanks Ian Gordon _ This e-mail has been scanned for viruses by the WorldCom Internet Managed Scanning Service - powered by MessageLabs. For further information visit http://www.worldcom.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS
-Original Message- From: Gordon,Ian [mailto:ian.gor...@edwards.boc.com] Sent: Thursday, January 23, 2003 7:15 AM To: 'IEEE EMC-PSTC GROUP' Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS All I would like to construct a Helmholtz coil to perform magnetic field immunity testing at DC frequencies and thus simulate the effect of a permanent magnet. There are some details on construction in EN61000-4-8 which details power frequency magnetic field immunity testing within the scope of the EMC directive. However the fields referred to are measured in A/m, whereas I need a field of, for example, 5mTesla. Can anybody advise me as to how to construct such a coil with a test volume of 0.5 x 0.5 x 0.5m and a field of 5mTesla? Thanks Ian Gordon Gordon, are you sure your numbers are correct? 5 milliTesla is equivalent to: 50 Gauss 4014 A/M 192 dBuA/M 194 dBpT and, if it were the H-field component of a plane wave: 1.5 million V/M 243 dBuV/M 6 x 10^^9 Watts/sq Meter I have a spreadsheet that calculates these values. I'll send you a copy off-line. Verify your requirements, and then we can find what you need to build. Ed This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS
Ian, Contact me off line and I will share with you the SW tools (free on the internet) that I use to do these calculations. The first is an antiquated tool that runs on DOS called Computer Calculus 4.0, or CC4 I like it because it's powerful but easy to learn and retain. The second is a 2D finite element analysis program called femm that is located at http://femm.berlios.de/ When you use the SW in asymmetric analysis you get true 3D values, so it's very powerful. You can use the program for plotting the B field over whatever effective area of interest you're after. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 From: Gordon,Ian ian.gor...@edwards.boc.com To: 'IEEE EMC-PSTC GROUP' emc-p...@majordomo.ieee.org Sent: Thursday, January 23, 2003 7:15 AM Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS All I would like to construct a Helmholtz coil to perform magnetic field immunity testing at DC frequencies and thus simulate the effect of a permanent magnet. There are some details on construction in EN61000-4-8 which details power frequency magnetic field immunity testing within the scope of the EMC directive. However the fields referred to are measured in A/m, whereas I need a field of, for example, 5mTesla. Can anybody advise me as to how to construct such a coil with a test volume of 0.5 x 0.5 x 0.5m and a field of 5mTesla? Thanks Ian Gordon This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS
All I would like to construct a Helmholtz coil to perform magnetic field immunity testing at DC frequencies and thus simulate the effect of a permanent magnet. There are some details on construction in EN61000-4-8 which details power frequency magnetic field immunity testing within the scope of the EMC directive. However the fields referred to are measured in A/m, whereas I need a field of, for example, 5mTesla. Can anybody advise me as to how to construct such a coil with a test volume of 0.5 x 0.5 x 0.5m and a field of 5mTesla? Thanks Ian Gordon _ This e-mail has been scanned for viruses by the WorldCom Internet Managed Scanning Service - powered by MessageLabs. For further information visit http://www.worldcom.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Helmholtz Coils
Surely, someone out there has the vector equations describing the magnetic field iof a classic Helmholtz coil. My vector equations class, being 30+ years ago, is just too dim. I keep getting the derivation wrapped around the axle. The centerline equation, H=0.716NI/r, is readily available; however, I want to analyze the interior volume and, if practical, the exterior volume. Jim Sketoe Boeing Company (314)925-4735 james.g.ske...@boeing.com
