Fan Power Consumption

I have a Lasko Premium 20" three-speed box fan. I'd like to know how many watts it uses, but so far I can't find any good info.

No wattage info on the box or the fan, no wattage info on the Lasko website.

Googling gets me wildly disparate numbers on wattage for "portable" fans.

Does anyone have reasonably accurate info? It would be nice to know how many watts for each of the three speeds.

Thanks.

--- Joe

Reply to
Joe
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If you really want to know the real numbers, rather than theoretical book numbers, which are next to useless, you can buy clamp-on amp meters for really cheap now. Then you would need an extension cord, where you (carefully!!) split the wires, leaving both insulated, so that one could be clamped around. These amp meters only work if one of the wires are clamped. If you use an extension cord, you can use it for all sorts of things around the house to see what they use too.

I was really surprised at how cheap these amp meters have gotten to be. They are accurate, too. I took one over to a certifying lab and they wanted to test it for free on a lark cause they couldn't believe anything that cheap would be worth a damn. Not many years ago, they cost hundreds, now they are down to $20 or so from here:

Reply to
Vey

Put a low value resistor in the neutral lead and measure the volt drop, if its an AC supply and the fan is an inductive load this won't be exactly accurate - but probably close enough.

Reply to
ian field

website.

With nothing much , other than clocks on in the house , take a reading on the billing consumption meter and then 10 minutes later. Then time for 10 minutes each of the 3 settings and consequential consumption readings

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N Cook

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170 watts
Reply to
tnom

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This is the next to useless number I mentioned in my post. It is the theoretical maximum amount based on the theoretical voltage. In the field, voltage can vary and so can the usage. I know it sounds nutty, but I've seen variations of more than 15% from the theory and that, to me, is unacceptable.

Reply to
Vey

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If +/- 15 % is unacceptable then the clamp on ampmeter you suggested from Harbor Freight would also be unacceptable.

Reply to
tnom

For an actual measurement, you could plug it into one of these meters:

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Reply to
John Popelish

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Don't assume. Buy it and test it like I did. The lab said +-3%. I consider that to be acceptable. If you don't like those numbers, then buy one for $300 and compare it to what you suggest the "book" numbers are.

Reply to
Vey

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Gee, if they are down to $20 that would be a good deal, too. Last I saw them, they were at about $35-40 and I thought was a bit too much for curiosity's sake.

Reply to
Vey

Hi Joe...

It's going to continue to be a bit confusing... google lasko fan watts and you'll find several entries that include comsumption.... but most say 170 watts, one says 165 watts, and yet another 70 watts.

There must be a rating plate somewhere on the machine or motor, though... isn't it a legal requirement?

Take care.

Ken

Reply to
Ken Weitzel

There's much better solutions than that, especially for the novice.

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I have one, it does a good job of measuring voltage, amperage draw, volt-amps, power factor, watts, and cumulative kilowatt-hours.

Reply to
James Sweet

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You still don't know what the power factor is with that route, a lot of cheap motors are closer to 0.5 than to unity, so the calculated wattage can be nearly double what the motor actually draws.

Reply to
James Sweet

I have an older GE 20" window fan. It only has two speeds, but here are the measurements:

Speed True watts Amps Volts Power Factor

Low 94 1.18 121.8 .6535

High 194 2.38 121.3 .672

Power was measured with a Yokogawa analog wattmeter; applied voltage and current with a Fluke 189.

This power factor is probably typical for an induction motor of this size.

Reply to
The Phantom

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If its a ventilation fan exposed to the great outdoors, wind direction could easily account for a 15% variation in power draw.

Reply to
ian field

I have a 20" Lasko in front of me at the moment. My Kill-A-Watt says

99/136/196 watts 129/175/248 volt-amps at 121 volts

And no, there is no electrical info plate or marking on any of several of these cheapie box fans that I own.

Bill Jeffrey

Reply to
Bill Jeffrey

Thanks a lot, Bill. Is your Lasko a model 3723? That's the one I have (two of, actually).

Also, I went to the Kill-A-Watt web site. It looks like you can't measure any appliance running at 220 volts, correct?

I have a wall A/C unit in my apartment that plugs into a 220 outlet. I read somewhere that even a fairly small one of these units uses 3500 watts. I imagine that the 3500 is only when the A/C is running the compressor. So the average wattage would depend greatly on the outside temperature, I would think.

--- Joe

Reply to
Joe

I have the UK version which is not even branded, but looking at it, it's obviously internally identical to the Kill-A-Watt. It's designed for 240V but works fine all the way down to 60V so I suspect the 120V model will work on 240V but have not opened one up to compare. At any rate the power supply is a simple capacitor and zener arrangement so it would be easy enough to modify with a lower value capacitor if the zener heats up too much on 240. If in doubt, it shouldn't be too hard to get the UK model and build some plug adapters as I did, back before it was widely available in the US.

I used mine to measure the draw of my 3 ton (36,000 BTU) central AC and found that the outdoor unit draws about 3500W with a power factor of 0.91. You're correct that current draw varies with head pressure which varies with outdoor ambient temperature. I doubt your window AC is bigger than 1 ton, so even with the indoor fan, I'd be shocked to see it drawing more than 2KW and really it's probably closer to 1200W.

Reply to
James Sweet

Hey, I found the "electrical info plate" on the Lasko. It was stamped into the sheet metal on the bottom of the fan. After being stamped, the sheet metal was painted, which obscured the stamped info so completely that the only way I can see it only with a bright light held at an angle. As near as I can tell, it says "Model 3723 (last two digits very unclear, could be almost anything) Style EC437 (again very unclear) Type 1 E20739 Listed 154C (UL symbol)

120v 2.2amp 60hz 1922.91"

Bill

Reply to
Bill Jeffrey

Having some issues with the landlord over your utility charges?

FBt

Reply to
Esther & Fester Bestertester

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