batsona
Maryland
join:2004-04-17
Ellicott City, MD
 ·Verizon FIOS
 ·Vonage
| reply to alphapointe
Re: X10 Appliance Module: Window A/C???
alphapointe: your link is a module I'd already looked at. Resistive load is 15A, while incandescent load is 500W. Does this tell me that something with a powerfactor of 1, can pull up to 15A of current, whereas something with a poorer power factor can pull much less? What's a window A/C unit more like, Incandescent, or resistive, or in-between? |
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alphapointe
Premium,MVM
join:2002-02-10
Columbia, MO
clubs: | I would say in-between. Since an A/C really just has two motors in it, it is an inductive load. |
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alphapointe
Premium,MVM
join:2002-02-10
Columbia, MO
clubs: | Here's a 20A 120V X10 outlet:
»www.smarthome.com/2243I/Leviton-···I/p.aspx |
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batsona
Maryland
join:2004-04-17
Ellicott City, MD | I have a more accurate reading now. I have a true-RMS meter, and wrote the VA measurement on the side of the AC. It says 523.
Would something rated for 15A (PF=1) and 500W incandescent be OK to pull 523VA thru? |
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nunya
SEE ROCK CITY 475 MILES
Premium,MVM
join:2000-12-23
O Fallon, MO
clubs:
·AT&T CallVantage
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Would something rated for 15A (PF=1) and 500W incandescent be OK to pull 523VA thru?
No. How can it be rated for 15A and 500W ? 15A at 500W = 33 Volts.
500W at 120v = 4.17 Amps.
If it says 500W, it means 500W. Not "a little more than 500W".
--
Looks like Reverend Wright got his wish - God Damn America. |
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SparkChaser
BURY BECK
Premium
join:2000-06-06
Downingtown, PA
·Verizon FIOS
 ·Comcast
| said by nunya  :
Would something rated for 15A (PF=1) and 500W incandescent be OK to pull 523VA thru?
No. How can it be rated for 15A and 500W ? 15A at 500W = 33 Volts. 500W at 120v = 4.17 Amps. If it says 500W, it means 500W. Not "a little more than 500W". The specs are a little suspect, to say the least 
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"Facts do not cease to exist because they are ignored." - Aldous Huxley
"I'm tellin' you, man, every third blink is slower" - Fillmore
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cdru
Go Colts
Premium,MVM
join:2003-05-14
Fort Wayne, IN
| said by SparkChaser :The specs are a little suspect, to say the least If you have ever dealt with anything from X10, you'd know that EVERYTHING they make is a little suspect. |
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nunya
SEE ROCK CITY 475 MILES
Premium,MVM
join:2000-12-23
O Fallon, MO
clubs:
·AT&T CallVantage
| reply to SparkChaser
Yeah, considering an incandescent load is purely resistive (for all intents and purposes).
I don't really care for the X10 stuff, but I do have some funny stories about it.
When people move out and leave the modules in, but no controls, many of the new owners are completely oblivious to whats installed. Then, lights start dimming themselves and coming on at all hours. It's funny. I've had quite a few "haunted" houses. The X10 is susceptible to interference from other sources, so it usually doesn't take too long after the move in date for the "ghosts" to show up.
--
Looks like Reverend Wright got his wish - God Damn America. |
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TheMG
join:2007-09-04
Edmonton, AB
 ·TELUS
| said by nunya :Yeah, considering an incandescent load is purely resistive (for all intents and purposes). Actually, there might yet be some logic behind that spec.
Incandescent bulbs have a very high inrush current when first turned on, which that X10 device may not be able to handle beyond 15A of inrush current. Something like that anyways. |
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Raphion
join:2000-10-14
Samsara
| said by TheMG :said by nunya :Yeah, considering an incandescent load is purely resistive (for all intents and purposes). Actually, there might yet be some logic behind that spec. Incandescent bulbs have a very high inrush current when first turned on, which that X10 device may not be able to handle beyond 15A of inrush current. Something like that anyways. Bingo, incandescent bulbs have HUGE inrush current, because the resistance of the filament is proportional to it's temperature. So when it comes on, it's cold and low resistance, and draws a surge of current till it gets hot.
I just checked the resistance of a 100 Watt incandescent bulb; it's 10 ohms, and 10 ohms at 120 volts is 120/10= 12 Amps! Surprising how much of a jolt those bulbs take to start up eh? It's an extremely short spike of current before the filament gets hot, but it still needs to be considered, especially with devices that use solid state electronic switches. |
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bemis
join:2008-07-18
Stoneham, MA
 ·Sprint Mobile Broa..
·Verizon FIOS
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| said by Raphion :I just checked the resistance of a 100 Watt incandescent bulb; it's 10 ohms, and 10 ohms at 120 volts is 120/10= 12 Amps! Surprising how much of a jolt those bulbs take to start up eh? It's an extremely short spike of current before the filament gets hot, but it still needs to be considered, especially with devices that use solid state electronic switches. I wish I had paid more attention in school... because what you said does not seem right.
It does not take 12A to start a 100W light bulb..... does it?
My living room has 5 100W bulbs on a single switch, so does that mean it draws 60A when I flip the switch to on?
I suppose it might be believable if the current draw is nearly instantaneous and so it occurs so quickly that there is no time for the fuses/circuit breakers to blow or the wiring to heat up... |
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cowboyro
join:2000-10-11
Shelton, CT
·AT&T U-Verse
·Comcast
·Optimum Voice
| said by bemis :I wish I had paid more attention in school... because what you said does not seem right. It does not take 12A to start a 100W light bulb..... does it? My living room has 5 100W bulbs on a single switch, so does that mean it draws 60A when I flip the switch to on? I suppose it might be believable if the current draw is nearly instantaneous and so it occurs so quickly that there is no time for the fuses/circuit breakers to blow or the wiring to heat up... Yes, the instant start current can be very high, but it's only for a fraction of a second. It could be up to ~17A/bulb (on the peak of the sine wave) if the resistance of the filament is 10ohm when cold. But it only lasts for a very, very short time. Even if it starts with the 17*5=85A, 8ms later it will be 0...
Haven't you noticed that bulbs tend to burn when you switch them on? |
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Waterbug
join:2008-03-30
| reply to Raphion
Incandescent bulbs ??? Are they still legal ??? Aren't they a MAJOR contributor to Global Warming ? Every time someone turns on an incandescent bulb, it probably kills a Polar Bear.
Sorry, I just couldn't resist. Won't be able to get my tongue out of my cheek for a week. |
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