And if you have more than one electrical panel, only the first panel (Main
Distribution Panel) has a Neutral - Ground bonding screw in place. All sub
panels are to have the neutral - ground bonding screw removed (frequently
not done).
73,
Gary - AB9M
--------------------------------------------------
From: "Jim Brown K9YC" <k9yc@audiosystemsgroup.com>
Sent: Wednesday, February 03, 2010 4:14 PM
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Subject: Re: [TenTec] High speed washer hum/whine
> 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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>
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