UPS, PWM Sine wave or True Sine wave

[banditpowdercoat]

High dollar Inverters I work with all the time at work, Industrial Electrician, All use PWM, not a true sign wave. We control speeds via frequency from 3Hz up to 400, All PWM. So no worries on a induction motor. The motor itself, The coils that its built form actually smooth the Pulsed waveform into more of a sign wave. And AC/DC supplies transform the power lower first through a transformer, a coil, then rectify to DC so no worries on PWM inverters for them either. Like I said, Only thing I ever noticed was small powerheads were a bit noisier. The PWM makes them chatter kinda like. Nothing bad. Just smaller motors with the high impedance coils.

And most all UPS run direct off the mains when the power is on, Only after the Mains is out, they swap over to battery. So, only running PWM when the power is out. Will be direct off the house sypply, bypassing the UPS electronics when the power is on