Line-and-Shaft vs. Electric Motors

[nw-mailing-list at nwhs.org]

It's very rare now, but there are still some 25 hertz systems around in papermills.  Some of these plants were built in the late 1800's and are still using turbine-generators that were installed in the 1920's and 30's.  A papermill powerplant might have 6 or more of these units.  They don't upgrade all at once, but retire the older units in sequence as they install new ones.  These days, not too many mills are upgrading, so the old equipment hangs on longer.  There were a lot of these old turbines in the Carolinas in the 1980's, in textile and papermills, but a lot of these plants are now closed.  We had one papermill still driving a paper machine with a twin cylinder steam engine in the early 80's, but they retired that paper machine around 1985.  That same mill originally had steam engines driving the generators (they have pictures).  You can go in the basement and see where they chipped down the old steam engine foundations and poured new foundations on top of them for the turbines they installed in the 1920's.
 
John Simmons

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Sent: Thursday, April 20, 2006 12:32 PM
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Subject: Re: Line-and-Shaft vs. Electric Motors


The following comment may be of interest.  It's from the chief electrical engineer on one of the major Northeastern railroads which runs catenary:
 

>>

The change from the old way resulted in the establishment of two
frequencies for AC power in this country. There was a lighting
frequency-which had to be relatively high, and an industrial frequency
that had to be relatively low. Using a low frequency for lighting
resulted in annoying flicker and stoboscopic effects, while using a high
frequency resulted in gear train installations to try to match the low
rpm machinery. 

Early industrial frequencies were in the range of 15 to 16 2/3 hertz,
and when the Niagara Falls hydro plant was built, a frequency of 25
cycles was decided upon as one could build 300 rpm motors and that would
match the steam driven machinery. 

That relic of the old steam driven plants resulted in many major
plants, shipyards, and railroads using single, two phase and three phase
25 Hertz until the rapid deindustrialization rendered this frequency
obsolete by the 1960's. 
<<
 
Oh, and by the way...  I used the wrong term.  The old machinery was not called "line-and-shaft," but rather "lineshaft."  I learn something new every day.
 
-- abram burnett

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