[SML] 50Hz Inverter results

[Jerry Durand]

I finally got all the inverter stuff settled.  The original seller gave
me a 50% refund and I get to keep the modified-square-wave inverter. 
Might sell it on eBay to break even (it works, just not for my needs).

The one I finally got is here, honest seller and fast shipping:
https://www.ebay.com/itm/Continuous-1500W-Pure-Sine-Wave-Inverter-DC-12V-24V-to-AC-220V-50HZ-Peak-3000W/282782882335

1500 W continuous, 3000 W peak, 50Hz, PURE sine wave.  I checked it with
my 'scope.  Slightly distorted sine wave but I've seen worse on mains
lines so 5 * on that point.  50.06Hz.  Draws about 24 W when idle, not
bad for the size of this inverter.

One detail, there are three ways to get a pure sine wave out of an
inverter.  They use the third which could cause some issues with around
0.1% of the stuff plugged in.  That 0.1% is probably the one critical
device you need so always check things before the show!  :)

Methods of getting a pure sine wave:
1. Tie one leg of the output to ground and ramp the other leg between +
& - voltage peaks. 

2. Ramp both legs exactly opposite to 1/2 peak levels.  This would mimic
USA domestic 240V lines.

3. Start with both legs at 0V.  Hold leg A at zero and ramp leg B up to
+ peak and back to zero.  Then switch BOTH legs at the same time to +
peak and then ramp leg A leg down to zero and back up to + peak. 
Repeat.  As long as your device doesn't expect either leg to be
referenced to ground you're good to go.

-- 
Jerry Durand, Durand Interstellar, Inc.
www.DurandInterstellar.com
tel: +1 408 356-3886
@DurandInterstel

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