On Wed, 27 Aug 2014 00:26:23 +0000, Ted Eckert <ted.eck...@microsoft.com> wrote:
> The FCC is generally not concerned with unintentional emissions from > construction machinery. The general assumption is that a susceptible > receiver would not be operating in close proximity to the > construction equipment. It may no longer be a correct assumption, > but that is the basis. It will likely be true in some cases. I can't > imagine a Caterpillar 797 operating in a residential area. However, > smaller pieces of machinery might be used closer to susceptible > receivers. The rules have not kept up with technology and they are > based on a time when the most significant ignition source in a > vehicle was the distributor and when digital electronics did not > exist in construction equipment. Actually I guess so, but couldn't find the fact and the rationale. I also sent an inquiry about this to FCC, but had no response at this time. > The general assumption is that a susceptible receiver would not be > operating in close proximity to the construction equipment. It may > no longer be a corre ct assumption, but that is the basis. It will > likely be true in some cases. I can't imagine a Caterpillar 797 > operating in a residential area. However, smal ler pieces of > machinery might be used closer to susceptible receivers. The rul es > have not kept up with technology and they are based on a time when > the most significant ignition source in a vehicle was the > distributor and when digital electronics did not exist in > construction equipment. Well, in the good old days, heavy machines were driven by diesel engines with no ECU, those arms were driven by oil pressure through manual valves and they usually don't have any electronic circuit, so I risk of EMC problems should negligible. However, these days, heavy machines may be equipped with electric/ electronic circuit including microprocessors, control circuits, inverter driven electric motors, sensors, etc., which can cause electromagnetic emission/immunity problems. Also, such heavy machines (smaller ones, if not Caterpillar 797!) may be used also in/near residential areas. General vehicles are still explicitly exempted by 47 CFR 15.103(a) and industrial machines are usually exempted by 47 CFR 15.103(b), but I couldn't find any exemption applicable to heavy machines in general. This raise me the question. > That being said, I'm not an expert in automotive EMC and I encourage > anybody with better information to amend or correct what I have > stated. (I would also like to know how you would run testing on a > Caterpillar 797. I don't think it would fit in many chambers.) If international standards are accepted, I think we can measure those emissions with CISPR 12 test method. Regards, Tom -- Tomonori Sato <vef00...@nifty.ne.jp> URL: http://homepage3.nifty.com/tsato/ - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
