[GreenKeys] Creed 7B with DC Only Mor

[Richard Knoppow]

On 2/23/2015 8:57 AM, Jeffrey D Angus wrote:
> On 2/23/2015 10:52 AM, Dave G4UGM wrote:
>>
>> why would any one want a DC only 160-250V motor?
>>
> Because some places actually had DC power instead of AC.
>>
>> Would it be run off the loop supply?
>>
> I wouldn't think so. There are still places in New York that are serviced
> by DC mains supplies.
>
> Looking back, an entire industry evolved around AC/DC capable things
> like transformerless radios.
>
>
      See    http://www.coned.com/newsroom/news/pr20071115.asp
     Con Ed ended DC service in Manhattan in 2007.   DC persisted in 
some other cities, see 
http://spectrum.ieee.org/energy/the-smarter-grid/san-franciscos-secret-dc-grid 
for San Francisco.  It was also common on board ships.  I searched for a 
list of cities that had DC power but coudn't find anything. FWIW, many 
areas of the US had 50 Hz power until the late 1940s, maybe later in 
some places.  In the Los Angeles area several of the small power 
companies supplying outlying areas ran 50 Hz. For instance Burbank did 
requiring Warner Brothers to have rotary converters to operate the RCA 
sound recording equipment which had synchronous motors.  The city, 
supplied by the DWP was 60 Hz so stores had electric clocks for both 
frequencies.

Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL