Please be very careful about applying W9IP's experience before his
good advice causes major property loss or someone gets badly hurt
or worse...
Capacitors must never -- must never! -- be connected to AC mains
unless they are clearly marked as X-Class or Y-Class.
No exceptions! Human life is at stake!
Capacitors not clearly marked as X-Class or Y-Class must never
--must never!-- be connected to AC line voltage. They must -- must! --
be behind a fuse or circuit breaker or other suitable AC line
protection device.
No exceptions! Human life is at stake!
Capacitors connected between AC line voltage and the AC neutral line
must -- must! -- have self-healing properties in case of arc-over.
Acceptable capacitors are always very clearly marked as X-Class,
Capacitors connected between AC line voltage and ground must -- must--
use a capacitor that will never -- will never! -- fail as a short
circuit from AC line to ground, which can compromise safety and human
life. Capacitors designed for safe connection between AC lines and
ground are always clearly marked as Y-Class
Safety first. Please!
73
Frank
W3LPL
On Fri, Oct 20, 2023, 2:32 PM <nlsa@nlsa.com> wrote:
> Dear friends,
>
> After re-winding the 3-core toroidal choke and adding some 1,000pF bypass
> capacitors to the AC input and VFD output, there is virtually no increase
> in
> my noise floor when the elevation subsystem is powered up. Maybe 0.1-0.2
> dB
> but I can't be sure.
>
> It appears that my EME system* has almost zero self-inflicted noise. Six
> weak spurs in the range 144.1-144.150 MHz. I'm happy.
>
> W9IP
>
> * (7) Raspberry Pi 3B
> (1) Intel NUC
> (1) Netgear ethernet switch
> Anan SDR, Homebrew: transverter, 1.5kW SSPA, TX polarity switch,
> and
> LNA
> Mitsubishi VFDs for Az & El
> APC switched rack PDU
> ... and their SMPS (no wall warts however)
> ...all mounted in the EME antenna's near field and controlled over
> fiber
>
>
>
>
> -----Original Message-----
> From: RFI <rfi-bounces+nlsa=nlsa.com@contesting.com> On Behalf Of Don Kirk
> Sent: Friday, October 20, 2023 7:24 AM
> To: jim@audiosystemsgroup.com
> Cc: Rfi List <rfi@contesting.com>
> Subject: Re: [RFI] Filtering 220VAC
>
> Hi Jim,
>
>
> You said "The neutral is NOT run to a 240V outlet, only the two phase (hot)
> conductors and green" and I think there needs to be a little clarification,
> especially for those that might be dealing with outlets that feed Ranges or
> Dryers.
>
> Back in the late 80's or possibly early 90's NEC required that for new
> construction 220 volt outlets for Ranges and Clothes Dryers must be 4 wire
> outlets (2 hot wires, Neutral, Ground) whereas before that time 220 volt
> outlets for Ranges and Dryers were normally 3 wires (2 hot wires and
> Neutral). Notice I said 3 wire 220 volt outlets used a Neutral (not
> ground), but in function there was very little difference since the Neutral
> eventually does tie back to ground in the panel box. I'm not an expert on
> the NEC rules so I don't know what if any additional changes have occurred.
> I do believe there is an exception (Grandfather Rule) to the 4 wire outlet
> situation if you buy a modern Range or Dryer if your house was built with a
> 3 wire 220 Volt outlet that allows you to use a conversion kit or follow
> instructions provided with the appliance that ties the Neutral and case
> Ground back together in the appliance.
>
> I only mention the above because I was recently asked about it by a friend
> who purchased a new Range and his house was an older home equipped with a 3
> wire 220 volt outlet so the information is still somewhat fresh in my mind.
>
> Just FYI, and 73.
> Don (wd8dsb)
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> RFI@contesting.com
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>
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