More on Magnum MS2000 issues, and a potential solution

Note: Make sure to click here: mvVikingStar.blogspot.com/.../summery-and-conclusion-compatibility.html for the final post in this series.

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As reported here: http://mvvikingstar.blogspot.com/2013/02/compatibility-issue-between-ms2000.html we have been having problems with the new Magnum sinewave MS2000 inverter while powering the Splendide washer/dryer. Over the past couple of weeks I have been sharing Emails with support departments, taking some more measurements and trying to see if we can find a workaround. Based on my conversations and Emails with support personal as well as distributes of inverters, I can say today:

• We clearly have an interaction between the Magnum MS2000 inverter and the Splendide Washer/dryer that renders the 'True Sinewave' anything but. (See waveforms below)
• It appears that other brands small washing machines and washer/dryers also have an issue with the Magnum products. One distributor I talked with installs dedicated Chinese sinewave inverters for this customers who want to run washer /dryers after having issues with the Magnum and Splendide as well as Bosch.
• We had no such issues when using the Prosine inverter, and I was told by support the Prosine seem to work well.
• Others from a Email list I subscribe to (3x total) have reported no issues with the Victron brand of inverters.

There needs only be one demonstration of a failure to prove a problem, while the absence of a problem does not prove anything. However, it does appear the Prosine inverter does not have this problem based on our experience and my conversations with tech support. While clearly the Magnum has an issue:

Original noted FAILING waveform.
'Hooking' in red are suspect.

I tried several approaches to moderate the waveform, ranging from unloaded induction motors (worked), to space heaters (also worked), a 40w light bulbs (did not work), hair irons (not work) and finally have settled on 15uF of 'motor run' capacitors located next to the washing machine. We have completed 5x runs now with no sign of an issue. Time will tell of this holds out. (and fyi: 7.7uF seemed promising, but the machine did show signs of struggling at one point during the 2nd trial run).

Someone is sending me some additional test equipment and I will be trying to gather more information - specifically current measurements and phasing. As I do I will continue to see what Magnum has to say (their current suggestion was 50uF of motor run caps, I have not found that many yet - and am working with 15uF). And when I get a more insightful answer, will post an update. Until then, it appears we have a 'workaround' that at least does not involve running the space heater at the same time (and wasting a tremendous amount of energy to boot).

The following are some additional waveforms I captured. Note that these were captured with the oscilloscope in an 'accumulate' mode - and show the range of waveforms over a long period of time. (as opposed to the one above which is a one time capture that I had to time just right to get.)

FAILING waveform - only Washer/dryer.
Note hooking.
Washer/dryer repeatedly exhibited faulty motion with this waveform

Added 7.7uF run capacitor.
Better - still some hooking.
Washer/dryer stumbled slightly during 2nd trial run.

With 15.4uF run capacitor.
Hooking almost gone -
But does have a flat/fat-spot at zero-crossing transition.
And still, this is nowhere near a 'TrueSinewave' waveform.
Have completed 5x trial runs with no struggling.

THIS is what it should look like!
This is shore power.
(And also the Magnum when not powering the washer/dryer!!!!???)

After making some more measurements will likely adjust the workaround. But for now, we seem to have found something that will let us leave the dock for the summer. Will post another update when I have new information.