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Re: [TenTec] High speed washer hum/whine

To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Subject: Re: [TenTec] High speed washer hum/whine
From: "Jim Brown K9YC" <k9yc@audiosystemsgroup.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Wed, 03 Feb 2010 14:14:43 -0800
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
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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