Customer: The “X” feature in my car doesn’t work right. Dealer: That’s okay. We think that it’s “better” to use something else.
That’s acceptable? Really? - Mark Sent from my Fuel Cell powered iPhone > On Nov 10, 2018, at 10:43 AM, Bill Dube via EV <firstname.lastname@example.org> wrote: > > There is no "ground" in a vehicle, only "chassis". (Unless the vehicle is on > charge and connected to the grid.) The drivetrain and the AM radio share the > chassis "ground", which is likely the root of the problem. > > The EMI comes from the controller PWM switching, goes into the chassis, (and > is radiated in general by the drive components,) and is received by the AM > radio. > > The AM radio can be filtered, but that adds cost, is difficult, reduces the > sensitivity, and likely the sound fidelity of the AM radio. The drive train > can be designed to reduce the EMI in the specific frequency region of AM, > which adds significant cost, and is _/very/_ difficult. You can locate the > sensitive components of the AM radio away from the drive train, which is a > bit difficult and adds cost. > > Is the cost worth the improvement of the AM radio reception? Most folks > don't care, and the added cost of clear sensitive AM reception is not worth > anything to them. Teslas answer is to "use streaming" instead of the AM radio > is probably the most sensible for most people. > > This problem is similar to acoustic noise in airplanes. It is quite > costly to reduce the cabin noise in airplanes, and it adds weight, which > reduces efficiency and reduces performance. In small airplanes, helicopters, > and military airplanes, everyone wears headphones (or ear plugs). In > commercial airplanes, the airplane itself is designed to reduce the cabin > noise. However, it is very expensive to solve noise the problem at the source > end. Much cheaper and lighter to solve the problem at the relieving end. > > Do you _need_ an AM radio in your car? Probably not. You don't get to > your destination any quicker. > > Bill D. > > > > >> On 11/10/2018 1:03 PM, Peri Hartman via EV wrote: >> Hmm, maybe cost savings of putting a grounded shield around the motor and >> controller. For the AM radio, what could the cost be? $1.00? >> >> Peri >> > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20181111/48d25efe/attachment.html> > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) > > _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)