[TowerTalk] Ramp up

[Andrew Williamson]

In message <20001108.113447.-79489.0.mainhart@juno.com>, Rick Mainhart
<mainhart@juno.com> writes
>Denis,
>
>What you are looking for is a DC motor speed controller. These are rated
>by horsepower and for a 90 volt DC motor can run off 115 VAC power.
>
>The features you are looking for ... soft start and ramp stop are typical
>features of these controllers. You may wish to look at Leeson, McMaster
>Carr, W.W. Grainger, or your local motor shop. Cost can run around a
>hundred dollars for a small (1/5 hp) well into the kilobuck range for a 5
>hp unit with additional features.


Interesting discussion.  Out of interest, is there an easy (and cheap)
way to ramp the speed of an AC motor and control the speed it runs at?
I know inverters can be used, but they are prohibitively expensive.  I'm
asking because we currently use 240V 1/2hp motors on some homebrew
rotators, but they turn a little fast..... (and yes, the 240V motors are
run from a residual current trip circuit, so they are fairly safe...)

Andrew Williamson GI0NWG / AC6WI
Homepage = http://www.gi0nwg.freeserve.co.uk/

One of the ZL9CI gang
http://www.qsl.net/zl9ci/

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