Westinghouse i4500 Generator

MNRon wrote:
Gdetrailer-
Not going to defend Westinghouse in depth, but their <3% THD is plenty good. AND I had the same behavior from a Yamaha 2000iS which I would consider a “high quality” generator (from previous thread). Additionally I know someone with same 5er and ACs (without Magnum) that can run not just one of the ACs with their Westinghouse i4500 but BOTH ACs as long as everything is off.

Bottom line, at this point I’m convinced there is something in my particular Magnum 3012 that doesn’t play well with genny s. Just spent another 30min with Magnum support, and they’re going to research and call back again tomorrow. The big question in my mind at this point is this anomalous behavior from my inverter? (Tech and literature suggest probably/yes) Or is this inherent in the Magnum design; in which case I probably will just add soft starts, but should have chosen Victron, but too late now.

Yamaha was clearly undersized for the task.

Westinghouse gen is the same Chinese import quality of Harbor Freight gens (most likely came from the same factories as HF gens).

Not the same "quality" between the two.

I would bet that the Westinghouse gen has far greater THD than 3% and that is most likely the issue.

There is a reason why a bigger Yamaha or Honda inverter gen costs considerably more than a Westinghouse gen.. It costs more money to design and build high quality PSW inverters even when the inverter is part of a gen. Many PSW inverters use a PWM (Pulse Width Modulated) "step" approximation of a sinewave. The speed and length of the pulses can be very fine (high quality looking sinewave) or they can be rather coarse (very poor looking sinewave with noticeable steps).

Think of this as similar to music files like MP3 where a low "sample rate" like 64 Kbps creates a terrible sounding audio file and if you increase the sample rate to 256 Kbps you end up with a near CD quality audio file.

HERE is a real good read on inverters that may help explain things better.

Basic PSW will use a "2 level" setup, the resulting waveform will look a lot like this (from the above link)..



Better PSW will use "3 level" setup, resulting waveform will be vastly improved like this..



Even better is a "5 level" setup which will result in even much better looking waveform.

Each "level" requires more parts which increases the cost..

Something else to consider, lower cost inverters may use "IGBT" outputs rather than MOSFETs, big difference in waveform quality, MOSFETS will result in far less distortion but it takes more MOSFETs to handle the power when compared to "IGBTs". IGBTs have limitations on how fast they can switch(ON/OFF) which limits them to a lower frequency (lower sampling rate) , MOSFETs are transistors which while can act like a switch, are considerably faster which allows for much finer high frequency switching (higher sampling rate).

Before barking up Magnums tree, borrow a old school 4Kw 120V non inverter gen. If it doesn't work, then consider it a fault of your Magnum.