Regardless of hum issues, the 220v 3 wire receptacles should be connected
to ground, not neutral. It's a safety issue.
Victor 4X6GP
On Tue, May 4, 2021, 04:26 <w5cul@sbcglobal.net> wrote:
> All,
>
> First Thank You to all who replied!!! I received a lot of replies off
> list,
> too many to answer individually. So I will attempt to answer all the
> questions in this one response as best as I can. It does appear that I
> need
> to add a little more detail surrounding my setup as a lot of the questions
> were centered around that, and then some about how the Amp was wired
> itself...etc. So here goes.
>
> It is a 3/6 cable with a ground wire that runs from the Main Electrical
> House Panel to a 4 Pole 50amp Dryer Receptacle in the bedroom. From there
> the sub-panel is plugged into the dryer receptable using a 4 Pole Dryer
> Plug
> (L1,L2,N,G) . 2ea 120Vac and 2ea 220Vac Circuits come out of the
> sub-panel,
> each with their own CB. One set of 120Vac receptacles are wired into L1,
> Neutral and Ground. The other is wired into L2, Neutral and Ground. The 3
> Pole 220Vac Receptacles are wired to L1, L2 and Neutral, more on that
> later.
> One gentleman asked me why 2 independent 120Vac Circuits, why not use just
> one 15amp Circuit for all the 120Vac needs? I split out 2ea so that I
> could
> balance the load across L1 and L2.
>
> Another Gentleman discussed a 4 Pole Dryer Receptacle versus the older 3
> Pole Receptacle, and that was much appreciated as it jogged my memory of
> how
> I had this setup at my father's house when I was having to take care of him
> in Mississippi. I did not run a dedicated 220Vac to the bedroom where I
> had
> a temporary station setup, yet just borowed from his Dryer Receptacle that
> was in the laundry room across the hallway when the dryer was not in use,
> which was not too often. And his Dryer Receptable was the older 3 Pole
> type, L1, L2 and N. And that answers why I wired the 220Vac Receptacle off
> the Sub-Panel that was feeding the Alpha at that time the way I did.
>
> The 220Vac line coming out of the Alpha is wired into a 3 prong plug, L1,
> L2
> and a "Green Wire". After re-reading the 87A manual this morning, it does
> say that the Green Wire can either be wired to Neutral or Ground, stated in
> that order. So, when I wired up the 220Vac Receptable all those years ago
> for use in my Dad's house, I wired the 3rd prong to Neutral such that the
> Alpha's Green Wire will be connected to such. The manual indicates it can
> be wired either way, to N or G. While under use at my fathers house, there
> was no low level 60Hz hum in the speakers, but then it was not a true 4
> pole
> service like it is here now.
>
> After coming back from Mississippi permanently, I just recently started
> getting this station back together. Keeping in mind that the Dryer Plug
> for
> the Sub-Panel was setup for 3 Pole and that it can plug into a 4 Pole
> Receptacle, I did use that arrangement to temporarily get power to test out
> the Alpha after the big move. During that recent testing, prior to having
> a
> dedicated 4 pole 220Vac Line installed into this bedroom, I did not
> experience any low level 60Hz hum with the Alpha plugged into the
> Sub-Panel.
> Keep in mind that all of the 120Vac equipment was being powered by the
> "Bedroom" Circuit at that time, not this new 4 Pole 220Vac Circuit. So
> this
> is prompting me to rewire the 220Vac Plug and taking the Alpha's "Green
> Wire" to Ground as opposed to the Neutral and see what happens.
>
> And lastly, a Gentleman asked me about Station Grounding, is all the
> equipment bonded together and is there a Station Ground. There is no
> Station Ground at this time, it is floating, or using the Ground that comes
> in from the 4 Pole 220Vac Circuit. I plan on installing such this weekend.
> Not just a "Ground", but an RF Ground that extends from ground rod to
> ground
> rod that are appropriately spaced from each other and that are bonded by
> copper shielding. As for the bonding of the equipment to each other, that
> is actually being accomplished by the Coax cabling that interconnects the
> equipment. The SO239 connecters are bonded to the equipment chassis, so
> when you connect up a Coax from one piece of equipment to another, you are
> affectively bonding those chassis together using the ground shielding of
> the
> Coax.
>
> So I think my first step is to re-wire the 220Vac Receptacle that is
> feeding
> the Alpha and see if that helps. If that does not eliminate the hum, the
> next is to replace the Caps in the Transformer Line in the Alpha, one may
> be
> leaky as one Gentleman said.
>
> Again, Thank You all for your replies, advice and guidance. I certainly
> have some more ideas now and a path to move forward with.
>
> Thank you,
>
> Mike
> W5CUL
>
>
> -----Original Message-----
> From: Amps <amps-bounces@contesting.com> On Behalf Of w5cul@sbcglobal.net
> Sent: Monday, May 3, 2021 12:26 PM
> To: Amps@contesting.com
> Subject: [Amps] Alpha 87A Power Supply Question
>
> Good Afternoon Gentlemen,
>
>
>
> I have a rather quirky situation and a question about it. I have been
> chasing down a low level 60Hz hum I get across my speakers when I plug my
> Alpha 87A into a shared A/C Service for the shack. I say shared because I
> am referring to a dedicated 6AWG 220Vac line that runs from the Main
> Electrical Panel for the house to the shack (bedroom). From there it is
> connected to a Sub-Panel that splits out 2ea 220Vac Lines and 2ea 120Vac
> Lines all with appropriate CBs. All the 120Vac equipment to include
> Transceivers, computers, speakers etc...are powered by the two 120Vac
> lines.
> The Alpha is powered by one of the 220Vac Lines. So as the issue goes,
> with
> all the 120Vac plugged in and powered up, transceiver turned on, white
> noise
> emanating from the speakers, the moment I plug the Alpha 87A into one of
> the
> 220Vac sockets, CB turned off, I immediately get a low level 60Hz hum
> coming
> out of the speakers. Since this sounds like a neutral or ground feedback
> loop, it prompted me to check the wiring on the Alpha. So I unplug the
> Alpha and perform a continuity check from Leg 1 of the plug to the chassis
> of the Alpha, Leg 2 to the Chassis and Neutral to the Chassis. As for the
> 120Vac Legs, there is no continuity to the Alpha Chassis. But there is
> direct continuity from the Neutral of the 220Vac Alpha plug to the Chassis
> of the Alpha. So the question I have is should the Neutral on the Alpha
> plug have such continuity to Chassis Ground, or do I have a bad Capacitor
> somewhere in the Alpha? I will say that the Alpha 87A does operate as it
> should and does put out full power.
>
>
>
> Thank you in advance,
>
>
>
> Mike
>
> W5CUL
>
>
>
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