lokakuu 14, 2019, 21:34:07 ip

Uutiset:

Tervehdys, kaksi samaan aikaan sattunutta teknistä muutosta / ongelmaa summa aiheutti vajaan viikon katkon foorumille. Nyt palvelinohjelmisto on jouduttu päivittämään uuteen ja sekä ulkoasu että toiminnallisuus on muuttunut. Toivotttavasti ei ainakaan kovin paljoa huonompaan suuntaan. Odottamattomia ongelmiakin saattaa ilmaantua.


Hydro Medium questions

Aloittaja cdamarco, tammikuu 01, 2010, 01:32:53 ap

« edellinen - seuraava »

calm

Lainaus käyttäjältä: AlexChupetinho - tammikuu 29, 2010, 19:36:45 ip
Anyway, the active-power (VA) of a LED lamp equals the apparent-power (W) since LED lamps don't consume
reactive power (so cos.fi equals 1)


Well, that is not so straightforward. :) Cosfii for compensated switching supply is usually around 0,95 and if there is no compensation it can be something like 0,6.. And if there is plain simple linear power supply it also has relative low cos fii. Of course reason for these are not tradidional current leading/lagging voltage but spiking current taken by rectifier-capacitor system.

AlexChupetinho

tammikuu 31, 2010, 10:15:10 ap #21 Viimeisin muokkaus: tammikuu 31, 2010, 12:27:17 ip käyttäjältä AlexChupetinho
 :-[  ???  - it strongly depends on what electrical consumer you have. I mean the LED lamp.
--

AlexChupetinho

Lainaus käyttäjältä: calm - tammikuu 30, 2010, 09:50:59 ap
Well, that is not so straightforward. :) Cosfii for compensated switching supply is usually around 0,95 and if there is no compensation it can be something like 0,6.. And if there is plain simple linear power supply it also has relative low cos fii. Of course reason for these are not tradidional current leading/lagging voltage but spiking current taken by rectifier-capacitor system.


Hi calm,

I've looked into the mather and I think you're right.
I don't think the lamp has a compensated switching supply so cos.fi for such a LED lamp can be quite low.
I've bought an new equipment for wattage and energy: "energy monitor 3000" by Voltcraft...
...but unfortunately I send the lamp back and got money back so I can't measure the cos.fi of the UFO anymore.
Anyway, the manufacturer pretended the lamp has a wattage of 90W. The measured wattage by me was 54VA so can the the active power be 90W???
--

calm

Lainaus käyttäjältä: AlexChupetinho - helmikuu 09, 2010, 23:16:36 ip
Anyway, the manufacturer pretended the lamp has a wattage of 90W. The measured wattage by me was 54VA so can the the active power be 90W???


VA2=W2+VAr2 so it is quite impossible that W would be bigger than VA..

denSiS


calm

Lainaus käyttäjältä: denSiS - helmikuu 17, 2010, 20:37:15 ip
Have a look at: http://www.plug.at/pl/calculator.htm

I´m new to the forum so be nice! :)


Nice calculator, but quite useless. :) There is a hidden constant 0.7 power factor there..

denSiS

Okay! Well i just bought a expensive ledpanel my self. The company that sells it told me that it´s quality stuff so i have to wait and see! They have 2 years of warranty so if it doesent work I´ll get my money back.