That is true for a lot of systems but in microwaves and inductive cooktops,
some power supplies rely on moving the trigger point up or down the sine
wave to control the output. I have a cooktop that will not run on most
inverters even some that say they are sine wave.
On Wed, Dec 9, 2020 at 4:13 PM Jim Miller via Gmclist <
> > I called Skill they replaced the charger even though I told them what
> happened. Turns out it was a square wave inverter, not even a modified
> > square wave, which manufacturers have the audacity to call modified sine
> wave inverters. I avoid Tripp-lite like the plague! Running the microwave
> > with a good sine wave inverter should be possible, someone knows what
> ovens and inverters will play well together, I don't, wish I could be of
> more
> > help.
>
> In general people tend to attribute too much importance to square /
> modified sine / sine inverter specifications. Most electronic devices do
> not care
> in any way whatsoever as to the incoming mains waveform because those
> devices have internal power supplies that immediately rectify the incoming
> power
> to DC and then process that DC either in a linear regulator or conversely
> in a switching supply that chops the DC back up into a form (either DC or
> AC) they need to use. Those experiencing problems with inverters not
> getting along with the electrical loads connected to them often experience
> these
> problems because of a poorly designed inverter control system, a poorly
> designed switching power supply in the load, or both. Inverters and
> switching
> power supplies have processors that figure out how aggressively to fire
> their power semiconductors and if these processors are cheap or poorly
> implemented then they see the instantaneous inrush load and consider it an
> overcurrent condition and trip offline rather than looking at dI/dt trends.
> Or they see sagging voltage and overcompensate for it by firing their
> output semiconductors too aggressively which results in an overvoltage
> condition.
>
> The square/sine distinction often only results in the load making
> electroacoustic racket such as whine or buzzing which is only cosmetic in
> nature.
>
> As with most any product the more expensive ones will have better
> implementations of control circuits that don't misbehave with overcurrent
> trips or
> overvoltage excursions. Sine vs square doesn't have a whole lot to do with
> it in my opinion based on my 35 years of electrical engineering
> experience.
>
>
> --
> Jim Miller
> 1977 Eleganza II
> 1977 Royale
> Hamilton, OH
>
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--
*John Phillips*
