[GreenKeys] Teletype motors

[WA5CAB at cs.com]

Sorry, but on VJ Day, the 1800 RPM synchronous motor was probably in the 
minority.  The US Army had bzillions of Model 14, 15 and 19 and the majority 
of them had governed motors which did not run at 1800 RPM.  Plus a 
significant proportion of the US fleet still ran on 115 or 230 VDC.  

In a message dated 06/17/2013 17:16:41 PM Central Daylight Time, 
nagle at animats.com writes: 
> On 6/16/2013 9:00 AM, greenkeys-request at mailman.qth.net wrote:
> >Message: 11 Date: Sun, 16 Jun 2013 10:45:11 -0400 From: Roy Morgan
> ><k1lky at earthlink.net> To: Steve <zarco at sonic.net>,
> >greenkeys at mailman.qth.net Subject: Re: [GreenKeys] model 15 gear
> >identification? Message-ID:
> ><8581478A-3A98-48A2-9B2E-60EFAC427A6B at earthlink.net> Content-Type:
> >text/plain; charset=iso-8859-1
> >
> >
> >On Jun 16, 2013, at 9:26 AM, Steve <zarco at sonic.net> wrote:
> >
> >>>Roy, I was able to identify the gear set from your list. They are
> >>>for a model 14 running at 75 wpm with a motor speed of 2100 RPM.
> ...
> >
> >I wonder what motors ran at 2100 RPM.  Seems to me that most of them
> >are 1800 rpm but I'm not sure.
> 
>     Synchronous motors for 60Hz power must run at 3600/N RPM, where
> N is the number of poles.  2100 RPM can't be a synchronous 60Hz motor.
> 
>     There is at least one ham web site that says 2100 RPM
> (http://www.rtty.com/development/teletype/model-14/model14.htm)
> but this seems wrong.  All standard Model 14 motors run at 1800 RPM.
> I have three working Model 14 tape printers, all with 1800 RPM
> motors running at 60WPM (45.45 baud).  Model 15 motors also
> run at 1800 RPM and are interchangeable with Model 14 motors
> (although the motor pinion and power connector are different).
> 
>    There were variations on this.  Teletype motors were
> available in DC (governed), 25Hz, 50Hz, and 60Hz.  But
> none of those frequencies will give you 2100 RPM.
> There's a two-speed governed motor variant.   Teletype Bulletin
> 1147B lists all the motor options for Model 14/15 machines.
> Most motors were made by General Electric, but a few
> were made by Oster, and some from the 1920s were made
> by Holtzer-Cabot.  I have one machine with a Holtzer-Cabot
> motor; it's noisier than the GE motors and has a heavier
> frame.
> 
>                 John Nagle

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20130617/0f006163/attachment.html>