UPS and Resmed

[capers]

I have read somewhere within this forum that one should not connect a Resmed machine to a UPS although it is apparently OK to connect a UPS to a Respironics.

I'm only interested in the Resmed machine so can someone explain why this is so.

[dsm]

I have read somewhere within this forum that one should not connect a Resmed machine to a UPS although it is apparently OK to connect a UPS to a Respironics.

I'm only interested in the Resmed machine so can someone explain why this is so.

The comments here will have been not to connect a SQUARE wave dc to ac power unit to a Resmed (el cheapo converter). It requires a PURE SINE WAVE dc to ac converter (better quality converter).

But both Resmed & Respironics machines can run off 12VDC, BUT, the Heated Humidifier won't operate on either. That requires a dc to ac converter & that is when the common sense applies to the wave form.

Good luck

DSM

[Paul56]

I have read somewhere within this forum that one should not connect a Resmed machine to a UPS although it is apparently OK to connect a UPS to a Respironics.

I'm only interested in the Resmed machine so can someone explain why this is so.

The only part of the Resmed machine that should *NOT* be used with a UPS is the humidifier.

The Resmed humidifier requires *PURE* sine wave power.

Most UPS units except the higher end models do not produce *PURE* sine wave power.

If you want to run the blower AND humidifier on a UPS then you will need to search for a UPS that produces pure sine wave power.

[bbeck4x4]

The m series humidifier is running off of 12v, (the entire machine runs on 12v) so I wonder if that humidifier would be ok with 12v operation? aka car battery.

[Debjax]

I am still so confused about what the difference is....What is the difference between *pure* sine wave and approximated sine wave?

[LoQ]

I am still so confused about what the difference is....What is the difference between *pure* sine wave and approximated sine wave?

If you took trigonometry, you should know what a sine wave looks like. If not, let me just say it looks like gently rolling hills alternating with gentle valleys. It goes through all of the values from 1 to -1 and back to 1 and so on. "Wave" describes it well.

The approximated sine wave is more squarish. Think of a graph with 1 for a time, then -1 for a time, then 1 for a time, etc. It's discontinuous, if that means anything to you. They're never totally square, but the closer to square, the less good.

[LoQ]

A picture is worth a thousand words. See the top two graphs on that page.

[bbeck4x4]

"pure" sine wave is what is coming from the wall socket, it is difficult to produce and therefore expensive to generate on your own, the 12v to 110v adapters that plug into your lighter socket are not "pure" they take 12 volt and step it up to 110 v DC and then flip it fast positive to negative, not a smooth sine, more stepped.

a hair dryer doesn't care, your laptop adapter doesn't care, but some sensitive electronics do, our cpap machines range in the sensitive.

when I go camping I just bring a optima 12v car battery, overkill for sure, but I know that I am good for a week running just the cpap, and I just recharge it with the car engine.

[capers]

The comments here will have been not to connect a SQUARE wave dc to ac power unit to a Resmed (el cheapo converter). It requires a PURE SINE WAVE dc to ac converter (better quality converter).
DSM

Many thanks for the reply, it all makes sense now.I've only ever run very high quality UPS's to my work machines and really didn't want one of those hulking beasts in the bedroom anyway.

And it's OT but a little known fact that firemen at least in Australia and the UK hate UPS's. The first thing the firemen do is cut off the electricity to a burning property, go inside and find UPS's pouring out 240 volts!

[dsm]

I am still so confused about what the difference is....What is the difference between *pure* sine wave and approximated sine wave?

If you took trigonometry, you should know what a sine wave looks like. If not, let me just say it looks like gently rolling hills alternating with gentle valleys. It goes through all of the values from 1 to -1 and back to 1 and so on. "Wave" describes it well.

The approximated sine wave is more squarish. Think of a graph with 1 for a time, then -1 for a time, then 1 for a time, etc. It's discontinuous, if that means anything to you. They're never totally square, but the closer to square, the less good.

Hmmmm,

A comparison that may resonate with some folk

Was just thinking of how breathing when working well, tends to look like a sine wave, rounded at the top (breath-in) and the bottom (breathe-out). Then some of us buy a bilvelel to help our breathing but bilevels put out a square wave of pressure that is, they tend to go up to ipap pressure in a straight line, stay at ipap in a straight line then when switching to epap, drop pressure in a straight line (apart from the rise time & cycle adjustments (slopes), they put out a square wave of pressure - up-along-down-along-up-along-down etc: etc: ). So there is a minor conflict between how we are naturally breathing & how the bilevel is trying to get us to breathe

Most bilevels try to impose their square wave delivery of pressure on our sine wave way of breathing. This conflict helps explain why some folk find bilevels a bit challenging. Also, why Resmed changed their vpap adapt to put out a sharkfin shaped pressure cycle then added that sharkfin shaped wave to the S8 model IIs as part of 'Easy Breathe'. Respironics created A-Flex to try to smooth out the pressure wave & it works well for some folk.

BUT, back to a square wave as an electrical voltage waveform. Square waves tend to mess capacitors up in the power supply. Some power supplies can handle them some can't (depends on the design). AC Electrical power delivered by your mains supplier is pure sine wave. Square wave power converters are the cheapest form of converter. Adding smoothing circuits to a dc to ac converter adds to the cost. Square wave is ok in some types of applications but as already discussed the Resmed machines specs say to use pure sine wave input if using a dc to ac converter.

ALSO

Using heated humidifiers at 12VDC. Most H/H units require 120VAC & won't run on 12VDC. When running off a battery, the S8 models detect that the voltage in is 12 VDC & disconnect the H/H. I am pretty sure the M series are the same. The H/H must have 120 VAC to run. The photos below show tests I ran on an S8 Escape with a H/H attached (of course the H/H won't run of 12 VDC !).

PHOTOS OF AN S8 RUNNING OFF 12VDC ...
http://www.internetage.ws/cpapinfo/s8-12vdc-1/

DSM

[bbeck4x4]

interesting here is what I have found on the respironics web page, a normal power inverter, under accessories here is the link, http://sleepapnea.respironics.com/acces ... power.aspx

although IMO it would be better to just use the 12v power directly, rather than converting the 12 to 120 then back to 12 at the brick power supply.
I know for a fact that the M-series runs completely from 12v as there is only one low volt cable going to the machine, much like a laptop.

I did send off a email to respironics to confirm use of the heated humidifier on 12v.

[billbolton]

but some sensitive electronics do, our cpap machines range in the sensitive.

The issue is not sensitive electronics at all.

An efficient way of controlling heating elements (such as used in humidifiers) is to use a power management approach which is generally termed phase control. For phase control to work you need a sine wave AC power input. The psuedo square-wave AC output from low cost DC to AC inverters is not adequate for phase control purposes.

Cheers,

Bill

[bbeck4x4]

you may be right, but when I turn the m-series humidifier over it reads 12v 4.16a, now my old respironics unit was 120 only as there was not a way to hook the 12v to it.

[dsm]

you may be right, but when I turn the m-series humidifier over it reads 12v 4.16a, now my old respironics unit was 120 only as there was not a way to hook the 12v to it.

I think you must be quite right re it running of 12v if that is the only power.

When I had a Puritan Bennett PB420S the heated humidifier didn't run off the power 'brick' but had to be provided 120-240 by a separate power cord. I have only known & seen ac H/H units - so it seems the M series actually provide a H/H that can run off a car battery.

DSM

[builta]

I am still so confused about what the difference is....What is the difference between *pure* sine wave and approximated sine wave?

If you took trigonometry, you should know what a sine wave looks like. If not, let me just say it looks like gently rolling hills alternating with gentle valleys. It goes through all of the values from 1 to -1 and back to 1 and so on. "Wave" describes it well.

The approximated sine wave is more squarish. Think of a graph with 1 for a time, then -1 for a time, then 1 for a time, etc. It's discontinuous, if that means anything to you. They're never totally square, but the closer to square, the less good.

Hmmmm,

A comparison that may resonate with some folk

Was just thinking of how breathing when working well, tends to look like a sine wave, rounded at the top (breath-in) and the bottom (breathe-out). Then some of us buy a bilvelel to help our breathing but bilevels put out a square wave of pressure that is, they tend to go up to ipap pressure in a straight line, stay at ipap in a straight line then when switching to epap, drop pressure in a straight line (apart from the rise time & cycle adjustments (slopes), they put out a square wave of pressure - up-along-down-along-up-along-down etc: etc: ). So there is a minor conflict between how we are naturally breathing & how the bilevel is trying to get us to breathe

Most bilevels try to impose their square wave delivery of pressure on our sine wave way of breathing. This conflict helps explain why some folk find bilevels a bit challenging. Also, why Resmed changed their vpap adapt to put out a sharkfin shaped pressure cycle then added that sharkfin shaped wave to the S8 model IIs as part of 'Easy Breathe'. Respironics created A-Flex to try to smooth out the pressure wave & it works well for some folk.

BUT, back to a square wave as an electrical voltage waveform. Square waves tend to mess capacitors up in the power supply. Some power supplies can handle them some can't (depends on the design). AC Electrical power delivered by your mains supplier is pure sine wave. Square wave power converters are the cheapest form of converter. Adding smoothing circuits to a dc to ac converter adds to the cost. Square wave is ok in some types of applications but as already discussed the Resmed machines specs say to use pure sine wave input if using a dc to ac converter.

ALSO

Using heated humidifiers at 12VDC. Most H/H units require 120VAC & won't run on 12VDC. When running off a battery, the S8 models detect that the voltage in is 12 VDC & disconnect the H/H. I am pretty sure the M series are the same. The H/H must have 120 VAC to run. The photos below show tests I ran on an S8 Escape with a H/H attached (of course the H/H won't run of 12 VDC !).

PHOTOS OF AN S8 RUNNING OFF 12VDC ...
http://www.internetage.ws/cpapinfo/s8-12vdc-1/

DSM

Hi,

The M Series Respironics units run exclusively on 12 volt DC. This includes both the XPAP and the Integrated Heated Humidifier.

So, it is my experience that on my Respironics M Series, I can run both the XPAP and the Integrated Heated Humidifier directly from the battery--been there, done that. I have run it with Heated humidity off my RV 12 volt battery and run it with heated humidity on AC power while running my gasoline powered generator (talk about noisy AC!). The Respironics M Series (see my equipment listing) just keeps running fine.

I hope that this answers the Respironics M Series with Integrated Heated Humidifier issue. No inverter required--it all runs just fine off of 12 volt DC. You can use an inverter (even a cheap square wave type) and then use the Respironics AC to DC power brick to convert it back to 12 volt DC but, that just wastes power.

The issue is with the Resmed is the control technology that they are using (as described previously by billbolton).

So, my take on this is that the Respironics M Series is a pretty good choice for people with 12 volt batteries. The power brick can be used with UPS but (using the Heated Humidifier will likely consume the UPS's reserve power more rapidly then using the humidifier in a pass over mode--setting dial to "0")