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 <ev@lists.evdl.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
>> 
> 
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