Line-and-Shaft vs. Electric Motors

nw-mailing-list at nw-mailing-list at
Thu Apr 20 12:31:53 EDT 2006

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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