Fully Variable Speed Control Unit for Lasko 2155A Window Fan

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/model_2155a.html http://www.airkinglimited.com/pages/industrial/window1.html
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Martin Levac wrote:

Consider a piece of cardboard and some duct tape. Jeeze!
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I cannot believe how difficult it has been to get technical information for the kind of three speed fan being discussed. I Googled various terms. Without heavy restrictions, millions of hits were made without solid information.
I did find something that showed how to switch from two-pole to four-pole operation on for a single phase induction motor.
I did find an ambiguous description on how to get three (or) more speeds from a universal motor by switching what would be the field winding of a series dc motor. Good fans seem to operate with motors without commutators. I do not know if universal motors are used with fans. I would think induction motors would be more reliable and cheaper.
If someone has good links, please pass them along.
I did get to a catalog posting of a motor controller, offered by Granger. I think it was a variable frequency drive. If so, the output voltage was not reduced at low frequency.
--

Sam

Conservatives are against Darwinism but for natural selection.
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On 6/21/2011 11:56 AM, HeyBub wrote:

That would have been funny 5 minutes ago. Alarm clock broken? Well, you know what to fix it with at least.
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Martin Levac wrote:

Everybody knows that and that's what I'm trying to explain. Heck, while I write this I have to have a gun in each hand and a knife in the other. But all is okay except for the few who drowned in an adjacent bog.
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"Martin Levac" wrote in message
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.
That's not what it means. It means they don't want any speed control devices on their fan.
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.
That may be so. But it's their design and I don't know what they are doing.
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.
Expected.
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.
Don't do it. Unless you don't mind the consequences.
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/model_2155a.html http://www.airkinglimited.com/pages/industrial/window1.html
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I don't know the details. It would be mighty peculiar controller that would change frequency without changing voltage. As a general rule, you should be able to run typical induction motors below synchronous speed by changing the frequency to less than line frequency. BUT you have to lower the voltage in proportion to the frequency so as not to get excessive no load current.
If you do that, the only consequence is lower maximum torque. For a fan, that should not be a problem.
This assumes that between your own controller and the actual motor itself there is no other controller or circuitry that does not like yours.
--

Sam

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On 6/20/2011 10:22 PM, Tom Biasi wrote:

Had nothing better to do tonight huh, Tom?
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"Martin Levac" wrote in message
On 6/20/2011 10:22 PM, Tom Biasi wrote:

Had nothing better to do tonight huh, Tom?
You are not obligated to consider anything that I say.
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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
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On 6/20/2011 10:55 PM, JIMMIE wrote:

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?
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Variable Frequency power inverter. The basic idea would be like taking a UPS and making the output frequency variable.. The real problem doing thiss is that the design of the motor is such that if you get very far away from 60 Hz with a cheap fan motor it is going to start to heat up. To get around this problem you will need a motor designed for it. We use such motors at work and they are expensive.
Jimmie
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A ceiling paddle fan is an induction motor. Get a paddle fan speed control, install it in a box along with an outlet and a cord. Like one of these: (Amazon.com product link shortened)08854747&sr=1-1-catcorr
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"Rich." wrote:

Better buy a fire extinguisher, too.
--
It's easy to think outside the box, when you have a cutting torch.

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On 6/23/2011 5:45 PM, Michael A. Terrell wrote:

Already covered. :)
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It's very unlikely that this speed controller works with induction motors. Most hand tool motors have brushes.
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wrote:

or wire an incandescent lamp dimmer to a duplex outlet,then plug in the fan(on high range). That's how I speed control my fixed speed model 270 Dremel Mototool.
--
Jim Yanik
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I am virtually certain that a that kind of tool uses a universal motor.
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Sam

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Again. Your dremel is a brushed motor, not an induction motor. What works for a motor with brushes doesn't work on induction motors.
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