SleepGeek wrote: ↑
Mon Jan 31, 2022 10:24 pm
I can't think of one DC powered device that will continue to run when voltage gets low much less overheat and damage itself. Can you point me to one?
I can’t fathom why you want to argue this, particularly from a position based on lack of factual evidence. Without knowing what the Resmed engineers considered in their design, nobody can say what they did or didn’t protect.
This cpap machine is not a simple mechanical device, but rather an electronic device with multiple semiconductors, sensors, and semiconductor-controlled loads (dc motor and two resistance heaters). Under-volted motors can draw current higher than designed, which can damage them and/or the components feeding them. Insufficient voltage to a mosfet gate can change is operating state, causing unintended current draws on the controlled loads. Insufficient voltage to a pressure sensor may cause an inaccurate reading. Etc. These are well-known, basic characteristics in electronics design. For more examples and failure scenarios, please consult some electrical engineering texts or use Google. I’m not here to teach electronics theory or perform Google searches on demand.
The bottom line is that some electronics devices can be damaged by low voltage, while many are not. We simply don't know the internal design of the AS11 or how Resmed tested, so applying less voltage than specified by Resmed carries a non-zero risk of damage.
Feel free to test under-voltage conditions on your own AS11. I have done enough electronics testing to know it isn’t a good idea without knowing whether the engineering design considered and protected for it. I am not going to risk my personal cpap to find out.
Please report back with your test results.