Author Topic: This neon power supply has a "cos" spec. of .99 does that mean  (Read 687 times)

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Offline BeaminTopic starter

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It says cos,then a little theta letter I think then say 0.99
https://youtu.be/U4n5vmpFtXw?t=796
The video starts at the label, also an interesting one to watch, I want to see him light up all the spectrum lights then put them into a splitter.

"cos .99": is that the power supplies way of saying dont feed square, triangle, or (most likely from its age) rheostat generated waves AC through it or you will damamage it? This looks rather old is that not an issue anymore? What would happen if you put square or rheostat waves into a modern cheap SMPS? Nothing? What about into a linear PS the good heavy ones from the pre 2000's(wall bugs) that were just two windings and minimal parts? I always keep those when I can find them, nice clean power for your projects, ordering one from china will set you  back 40 bucks.
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Offline AlbertL

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Re: This neon power supply has a "cos" spec. of .99 does that mean
« Reply #1 on: August 30, 2021, 12:42:32 am »
"Cosine phi" is - more or less - the "power factor" of the device.

This explains the two terms: https://cache.industry.siemens.com/dl/files/748/51402748/att_88178/v1/faq_51402748_e.pdf
 
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Offline BeaminTopic starter

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Re: This neon power supply has a "cos" spec. of .99 does that mean
« Reply #2 on: August 30, 2021, 05:11:18 am »
"Cosine phi" is - more or less - the "power factor" of the device.

This explains the two terms: https://cache.industry.siemens.com/dl/files/748/51402748/att_88178/v1/faq_51402748_e.pdf

"Cos phi results from the ratio of effective power (P) to fundamental apparent power"

So the manufacture is concerned with the power factor and not the shape of the wave? I wouldnt think that would matter in something small unlike a big motor.

so .99 represents almost perfect power factor? Where would you plug that into the equations on that pdf link page ?

What does happen when you run a power supply over a rheostat or other funky nonsine waves.
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Offline james_s

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Re: This neon power supply has a "cos" spec. of .99 does that mean
« Reply #3 on: August 30, 2021, 05:28:08 am »
Unity power factor is 1.0, like a purely resistive load. True power and apparent power exactly the same. On a small scale power factor isn't really a big deal but think about it on a larger scale. You could have many thousands of these things operating around the country along with countless other devices. It all adds up, and you end up with megawatts of reactive power which results in a large amount of wasted energy in transmission losses and wasted capacity of the power grid. You're billed based on true power but the wires and transformers and such have to be sized based on apparent power because it's the current that heats up the wires.
 


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