On Jun 21, 12:50*am, Martin Levac wrote:
On 6/20/2011 10:55 PM, JIMMIE wrote:





On Jun 20, 5:21 pm, Martin *wrote:
Hello,

I have a Lasko 2155A window fan with integrated 3 speed control unit
(links at the end of this post). I want to be able to fine tune the
speed so I want a fully variable speed control unit that I would attach
to the power cord, and control the speed from there instead.

The operator's manual states that the fan must not be used with a solid
state speed control device. I understand that to mean that I must not
simply attempt to vary the voltage, i.e. from 120VAC to 90VAC for
example. I understand that this may cause the amperage to rise, and all
sorts of nasty things may occur after that.

I read a little about the problem and I believe that the integrated
speed control unit controls the speed by varying the AC frequency while
maintaining the same voltage, i.e. from 120VAC 60hz to 120VAC 50hz and
so forth. Though I don't actually know.

I sent a request for information on how to do what I want but I got the
standard "don't do it" reply. As if by some magical mysterious way, I'm
going to change my mind. So no luck from the manufacturer.

I've looked at the Air King 9155 model and I believe it's the same as
the Lasko 2155A. Somebody correct me if I'm wrong. I also believe Lasko
doesn't actually manufacture that model, they only sell it. So that
might explain why I got the standard "don't to it" reply from them. I'll
ask Air King next to see if I have better luck with them.

If any of you have experience with this kind of thing, please advise me
on how to proceed. If there's already a device that I can buy and just
plug in, that would be best. If there's some tinkering to do, it would
depend on the depth and complexity of that tinkering.

Actually what would be best is if I found a similar window fan with an
integrated fully variable speed control unit. Alas, the available choice
of window fans pretty much stops at Air King. Though I understand that
there's a slew of window fans that are not made anymore, like the
Vornado for example, so that might be an option. However, my primary
consideration of any window fan remains a fully variable speed control unit.

Thank you

Martin Levac

http://www.laskoproducts.com/fans/mo...//www.airkingl....

The motor is an induction motor, as far as you are concerned this
means the speed is locked to the frequency of *the AC line. There are
some tricks in rearranging some connections to the stator winding to
get some different speeds but 3 different speeds are about the limit.
I haven't looked but I bet if you google variable speed induction
motors you will get a lot more info.

Jimmie

Since the speed of the motor is locked to the AC frequency, and since
I'm not about to fiddle around the insides of that motor, then it means
I want a device that controls the AC frequency at the power cord. Any
idea how to proceed, Jimmie?- Hide quoted text -

- Show quoted text -

The problem is that you can't simply continue to lower the frequency
as the lower the frequency the less effective the induction is. Also
you will find that variable frequency controllers are pricey.

Your best bet is to find a motor with brushes that you can vary the
speed of with common speed controllers.