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
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Reply to
Martin Levac
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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
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Reply to
Tom Biasi
Had nothing better to do tonight huh, Tom?
Reply to
Martin Levac
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
Reply to
JIMMIE
@Martin:
You can not turn a consumer appliance with a cheap induction motor into a perfectly adjustable device with the same precision of a VFD motor... First off, the variable frequency controller would cost more than the fan you want to run with it...
The cheapo motor the fan is currently equipped with has several windings in it which are energized in the same way a 3-way light bulb is configured... Low setting is a smaller winding -- Medium speed is a larger winding and Hi speed is all windings on at once...
The bigger question here is why you need to have a totally adjustable window fan unit -- and just how insane you would be trying to obtain something which just doesn't exist...
~~ Evan
Reply to
Evan
Evan, I think you missed ^ this part when you replied.
The OP has indicated that it would take magic to change his mind. Unless you're feeling up on your mojo, I'd give this one a pass.
R
Reply to
RicodJour
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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?
Reply to
Martin Levac
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From where I'm standing, you're no help at all, Evan. Which brings me to my next question, can you turn a perfectly useless usenet poster into a productive and useful usenet poster? And just how insane you would be trying to obtain something which just doesn't exist...
Reply to
Martin Levac
Oh the irony. You do realize that you just told somebody "don't do it" it being him telling me "don't do it", and on newsgroups that deal with subjects that have pretty much zero tolerance for that kind of bullshit, right?
Reply to
Martin Levac
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.
Reply to
Salmon Egg
In article , Evan wrote:
There may be some tricks I do not know about but the only way I can think to make cheap three speed induction motors that are also reasonably efficient and without costly electronics is to switch the wiring to change the effective number of poles.
I am now curious enough to look that up.
Reply to
Salmon Egg
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.
Reply to
jamesgangnc
I did find that. Cheapest VFD at a glance was $325. Although I don't see why they should be. Maybe these things are too specialized to be made cheaply.
It's a fan and there's little I can do about its design. It must be quiet and that is partly why I want full control over the speed.
Reply to
Martin Levac
That's part of it. There is not a high demand. Theoretetically an inverter design could be adapted to a variable frequency output. But you still have to convert to dc, then convert back to ac with a variable frequency switching supply of some sort. And you are still limited by the ability of the induction motor to operate at lower frequencies. Even 30hz, which is just half, is far worse at induction.
Practically all small fans will be built with an induction motor and speed control will be done via multiple sets of windings. Brushed motors are more costly and have issues with brush wear and electrical noise. They are seldom found in home appliances. I have seen them in blenders though. Probably because blenders have a lot of speeds.
Your most effective solution, barring finding a fan with a non induction motor, would be to replace the motor. That will probably involve some minor fabrication unless you are really lucky. Another option would be a DC motor and a variable output dc power supply.
But as you have found, there is no simple plug in solution for your problem.
Perhaps a smaller fan. Or put the fan in a window further away from you. If you leave the nearby window open you will still be in the cross breeze.
Reply to
jamesgangnc
There's little you can do? Come on, Sparky! Design and build one yourself. It's not magic. Build a bank of 12v computer fans - they're quiet enough. Or spring for a fan that does what you want without 'fixing it'.
BTW, I'd never tell someone not to do something that has the potential of keeping me entertained.
R
Reply to
RicodJour
Had nothing better to do tonight huh, Tom?
You are not obligated to consider anything that I say.
Reply to
Tom Biasi
Consider a piece of cardboard and some duct tape. Jeeze!
Reply to
HeyBub
YOU ARE NOT going to find a cord control capable of what you want to do... You could build a controller to do what you want but it would need to be in a large metal box like the motor controllers for industrial motors and HVAC equipment get installed in... Remember (Variable Frequency Drive)...
You are asking something along the lines of "how do I install cabinet rated electrical equipment into an extension cord control"...
Get the picture ?
~~ Evan
Reply to
Evan
+1 to this...
A DC motor in a fan will be easier to control in the manner you desire and wish to control your fan in for whatever unknown and insane reasons.you have yet to disclose...
~~ Evan
Reply to
Evan
We all know what you did. It wasn't your smartest move.
Reply to
Martin Levac

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