[R-390] R390A power cord specifications

[John Wendler]

Gary and Jim,  thank you for the detailed replies.  That was exactly the
kind of authoritative info I was looking for.  The drawing dates to 1956,
so I’m not surprised by the lack of ground wire.  The connector on the
radio end surprises me - both of my radios have studs for circular crimp
lugs.

On Thu, Dec 29, 2022 at 1:26 PM Jim Whartenby <old_radio at aol.com> wrote:

> Drawing title block says for R-390A/URR & R-392/URR ????
>
>
> Jim
>
> Logic: Method used to arrive at the wrong conclusion, with confidence.
> Murphy
>
>
> -----Original Message-----
> From: gary.biasini at shaw.ca
> To: 'John Wendler' <wendlerjrv at gmail.com>; r-390 at mailman.qth.net
> Sent: Thu, Dec 29, 2022 10:48 am
> Subject: Re: [R-390] R390A power cord specifications
>
> John,
>
> Please see attached.
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> On
> Behalf Of John Wendler
> Sent: December 29, 2022 8:56 AM
> To: r-390 at mailman.qth.net
> Subject: [R-390] R390A power cord specifications
>
> Does anyone have an authoritative specification on the power cord for the
> as-shipped R390A?  I do not see a length requirement in MIL-R-13947B and
> have not yet spotted a part number in the manuals that I looked at.
>
> The power requirement (275 Watts, max) in conjunction with the lower
> voltage
> (115 VAC) says the maximum current that cord will carry is about
> 2.4 Amps.  The brackets that capture the power cord on the rear panel set a
> maximum outer insulation diameter of approximately 0.36 inches. 18/3 SOOW
> should work, but I was wondering about the historical lore.  I expect that
> installers would have chopped or replaced as necessary for a neat
> installation.
>
> As an aside, one of my units came with a plug that had a rotatable ground
> pin for use with either 2-wire or 3-wire power outlets.  Point the pin
> forward for 3-wire outlets; rotate it 90 degrees out of the way for the
> 2-wire outlets.  The ground wire is secured by a lug to the screw that the
> pin rotates around.
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>