Yea, you are right. But that actually changed quite a long time ago in
fact. Talk about dangerous !
----- Original Message -----
From: "Ariel M. Elam" <k4aal@comcast.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Wednesday, February 03, 2010 10:57 PM
Subject: Re: [TenTec] High speed washer hum/whine
> Until a few years ago (or maybe more than a few as I age) National
> Electrical Code only required a 3 conductor cable to feed a clothes
> dryer. There were two hot conductors (220 volts for heat) and one
> combination ground & neutral conductor fastened to the dryer cabinet
> which in combination with one hot furnished 110 volts to power the drive
> motor. This has changed and the NEC now requires four conductors - 2
> hots, 1 neutral, 1 ground. This also applies to electric ranges.
>
> Maybe this sheds a little info.
>
> 73,
>
> Ariel, K4AAL
>
> Jim Brown K9YC wrote:
>> On Wed, 03 Feb 2010 15:27:36 -0600, Stuart Rohre wrote:
>>
>>
>>> The problem may be Variable
>>> Speed Drives in the appliance, lots of modulated semiconductors
>>> controlling the motor for "Green" efficiency. Oh, the laws of
>>> unintended consequences from the environmentalists!
>>>
>>
>> Don't blame environmentalists -- it's lousy circuit design.
>>
>>
>>> There are no guarantees with line filters.
>>>
>>
>> This doesn't sound like a line filtering issue, but it DOES sound
>> like possibly improper connections of neutral and the power system
>> green wire, or a missing power system green wire, of missing bonds
>> of station ground to the rest of what's grounded. These improper
>> connections could be in the shack or at the appliance.
>>
>> Some things to check. 1) Make sure that the green wire is bonded
>> to the chassis at the power supplies, AND where the power supply
>> is plugged into the AC outlet. 2) Make sure that the chassis
>> (green wire) is NOT connected to the neutral. 3) Make sure that
>> your power system ground (green wire) is bonded to everything else
>> in your station, and that every chassis in your station is bonded
>> together. 4) Make sure that the common point of your station
>> chassis bonds (grounds) is tied to the ground rods for your
>> antenna system, your shack, the power system ground rod, and the
>> ground for Telco and CATV arrestors.
>>
>> Look for #1 and #2 at the appliance that is generating the noise.
>>
>> 73,
>>
>> Jim K9YC
>>
>>
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