Tarhead

Wonderful, wonderful - yes the label on the  machine shows 110-240v so looks like I am OK............... woohoo

Thanks you for your response.

C-paps in Oz are very expensive (AU$1800 plus extra for  humidore and accessories)

I am so thrilled that I am able to use this machine - no worries and  appreciate the help of this forum to put my mind at rest.

Many Thanks


Jenny
No longer 'blonde' LOL

Bill Bolton wrote:

el_zorro wrote:

so if you have a 2 AMPs of current, 1 AMP would flow on each wire.

2 amps flows in each wire as they are part of the one electrical circuit.

Your electrical theory is quite wrong.

Cheers,

Bill (professional member of the Institute of Electrical & Electronic Engineers)

Bill,
There is no theory here but AC and simple math. For single phase AC:

Wattage=Current(I) * Voltage

Wattage of an Autoset II = 275W

For 220V: 275= I * 220
I=1.25

For 110V: 275= I  * 110
I=2.5
 
BTW, my cheap walmart cord is rated for 13AMPS at 110V and is 14 gauge wire, way more than a CPAP will require. I'm not sure where a 20 gauge wire would come from in the US, other than used for a doorbell or something, it certainly would not be used for AC.

Us Yanks aren't very smart but we can do simple math. I used to be an IEEE member myself and learned a lot about computer theories and discrete circuits from the white papers in their journal but I learned my AC from my good old granddad who didnt graduate high school but knew more about AC than most college professors.


_________________
Therapy started on Dec. 21, 2009
ResMed Mirage SoftGel nasal mask
Phillips Respironics REMstar Pro System One with C-Flex+ and heated humidifier at 11 cm.
Travel/Backup Machine ResMed S8 Autoset II with EPR and H4i heat humidifier at 8-11.6cm.

I have seen 16 ga extension cords and I have had a few small appliances, such as clocks and aquarium air pumps, with 16 or perhaps even 18 ga cords (this was long ago).  Mini Xmas tree light sets (35 or 50 lights) use light gauge wire, 18 ga?

I learned Ohm's law and other electronics stuff in high school; we mostly learned about tube circuits, although we did learn about transistors.  It was a vocational radio and TV course and at that time, most TVs had solid state rectifiers, but every other circuit used tubes.  

In the Air Force, I re-learned basic electronics, but with much more solid state and logic training.  In the Air Force I repaired electronic warfare receivers and transmitters with several types of high power RF tubes, including TWTs and BWOs.  I also worked for a year in an Air Force job where I designed and built RF detecting and jamming circuits.  I have never been an IEEE member, but many of my jobs after getting out of the Air Force, including my present job, had "engineer" in the title.

Bearded, I stand corrected, the walmart cord is 16 gauge. I have seen some 18 GA like you said in lights, etc. but havent seen 20 GA in the US for AC. I wasnt trying to pick any kind of a fight here just to make sure that people know that a less expensive cord can be used for CPAP without worrying and using it for 220V actually allows the cord to provide more power because the amperage is half of what it is capable of handling.

To Bill, I have read many of your posts and you are highly respected and regarded here, I made the comments with all due respect. To clarify my response, the 220V applications use half of the current but as your answer states both wires are used, each wire is 180 out of phase with the other and each carry half of the current that a polarized 110V cord would use.


_________________
Therapy started on Dec. 21, 2009
ResMed Mirage SoftGel nasal mask
Phillips Respironics REMstar Pro System One with C-Flex+ and heated humidifier at 11 cm.
Travel/Backup Machine ResMed S8 Autoset II with EPR and H4i heat humidifier at 8-11.6cm.

el_zorro;  I just thought that Wal-Mart may have had a deal on 14 ga extension cords.  :)

el_zorro wrote:

Bearded, I stand corrected, the walmart cord is 16 gauge. I have seen some 18 GA like you said in lights, etc. but havent seen 20 GA in the US for AC. I wasnt trying to pick any kind of a fight here just to make sure that people know that a less expensive cord can be used for CPAP without worrying and using it for 220V actually allows the cord to provide more power because the amperage is half of what it is capable of handling.

The issue with cheap US extension cords sold for 120V AC applications is generally the insulation rating, not current carrying capacity.

Cheers,

Bill