Xantrex XW, Generator not being qualified until load applied to generator

Les Nagy · July 2010

Hello:

I have been reading theses forums for months. I have been living off the grid since middle of March here in Chile. I have a Xantrex XW4548 export inverter, MPPT60-150, and 9 Kyocera 205 panels.

I have no problems here with getting enough sun, but the batteries I purchased here in Chile are faulty and the seller is not honoring his warranty. That is another story altogether but I have "good" batteries on the way form the US.

My problem with my batteries has forced me to buy a generator to keep things going some nights when I am drawing more power than the batteries will provide. So I purchased a Kipor KGE 2500X. It runs well, can supply its rated 2000watts all night, and is relatively quiet. My problem is that the XW4548 will not qualify its output until I load the generator with about 700 watts or more.

I looked at the waveform on my oscilloscope and it shows a relatively correct sinewave but it has a 2.4KHz component to it that I think is the culprit. Running a microwave on it for 1 minute allows the XW to qualify it and then switch over. Once switched over and running a charge to the batteries, I can run the generator all night with varying loads up to its rated output with no problems.

So I am looking for a solution to get the XW inverter to qualify it without all the hassle of connecting a load manually and switching everything over once it is online.

Someone I talked to at Xantrex suggested using a motor starting capacitor to clean things up so the inverter would switch over. I do not know what values would be suitable for the capacitor nor whether it should be left in circuit or dropped out once the inverter qualifies the generator output.

I am open to suggestion of all kinds, except for returning the generator.

Thank you in advance for any help or advice offered.

RCinFLA · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

The only possible source that I can imagine of a 2400 Hz component on the 60 Hz is the AVR regulator. It may be pulsing current into the field winding at this frequency.

The usual reason for inverter not locking on generator is frequency being off or wobbling around 60 Hz at a rate too fast for the XW to catch phase lock.

Even though the XW specs 55 to 65 Hz it can not tolerate too fast a wobbling of the frequency while it is trying to aquire phase lock. Many generators with stepper motor throttle control have a frequency wobble at no load. At no load, the single increment of the stepper motor yields a wider variation in engine speed. If you listen to engine you can detect the wobble in the sound of the engine.

Putting a load on the generator loads the engine and opens the throttle plate more into a area where the variation per stepper motor increment is less.

Les Nagy · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

I do not hear any frequency wobbling, and the waveform appears quite stable with no load, only that the 2.4KHz component seems to go away when loaded. I am sure that is what I saw when I looked at it before but will have a look again.

I do not believe this has a stepper motor for throttle control as I see the usual arm and spring arrangement as all the other mechanical speed regulators I have seen. I would still like to know about the capacitor value. Something like 50 Mfd if it is the solution?

BB. · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

Are you guys 230 VAC 50 Hz?... Anyway, I would suggest a much smaller motor run capacitor of around 5 to 7.5 Mfd (micro farads) and ~370+ VAC rating for fractional Horse Power motors.

A 50 Mfd capacitor is for a much larger horse power motor and would draw a lot of current from your genset (could overheat your wiring/alternator).

If the 7.5 Mfd does not fix the problem, you could probably double the value--but I would not use a 50 Mfd one--just too large (in my humble opinion).

-Bill

Les Nagy · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

Yes we are 230/50 here. I am a Canadian who moved here in January BTW. I will try the smaller cap. and see what happens, if I can find one here!

niel · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

i might suggest an even smaller value of capacitor as you do not want the cap dissipating too much power. at 50hz a 1uf cap will give a capacitive reactance of 3183 ohms for a current of about 73ma. at 230v this is 16.62w. if you used 5uf this would be 637 ohms and it would be 361ma and 83w of power dissipated. in any case if the cap works at eliminating the initial problem then it can be switched out of circuit once lock is made.
btw, at 1uf the capacitive reactance at 2400hz is 66.3 ohms so the 2400hz signal should be attenuated a great deal.

Les Nagy · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

I don't know I didn't think of doing the simple math to determine the reactance... I guess I thought there was some special secret sauce to working with motor caps and loading AC generators.

1 to 5 Mfd does seem to be the range of interest. 50Mfd would have made a nice heater!

Thanks for the information.

In case anyone cares, my move to Chile is on a blog at http://lesnagy.ca where my power setup can be seen.

niel · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

i see an excellent example of buss bar usage on your batteries.:D

no need for you to do the math as i did it for you.;)

let us know if you try the cap and if it works for you.

Les Nagy · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

The buss bar was the cheapest way, and surest way to go for me. Using 5 banks was less than optimum but everything works fine except for the darn batteries being junk.

I have 12x 250Ah AGMs on the way and hopefully soon I will be able to fully utilize my system. In the desert here AGMs just make more sense.

solorone · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

I had a tour of your links, very nice setup.
Photography being my hobby, I really think you part of the world is beautiful. I have friends who have journeyed into the high desert. I once saw a show on Nature, and it focused on the desert and mountains, just beautiful, and so rugged.

If I had unlimited money, I would surely spend 6 months there taking pictures.

niel · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

is that the same show that said the desert hadn't received rain in many thousands of years and was focusing on fossils and stuff in addition to current life in the desert? if it is that same one, i enjoyed watching it too. temps are generally warmer in south america compared to north america.

solorone · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

niel wrote: »

is that the same show that said the desert hadn't received rain in many thousands of years and was focusing on fossils and stuff in addition to current life in the desert? if it is that same one, i enjoyed watching it too. temps are generally warmer in south america compared to north america.

Most likely, it covered a long range of the Andes, many desert areas and referred to the Andes as the dragons back. I watched via my antenna, so it was an uncompressed HD signal, awesome images.

If I had the money, I would buy a few more choice pieces of Nikon glass, hire a couple of folks and stay there a couple of seasons taking pics.

mike95490 · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

Be sure you get a motor RUN cap, not a starting cap. A starting cap will last 10 - 15 minutes, then goes boom.

BB. · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

mike90045 wrote: »

Be sure you get a motor RUN cap, not a starting cap. A starting cap will last 10 - 15 minutes, then goes boom.

I wonder how you know that factoid?

:D

-Bill "duck and cover" B.

mike95490 · July 2010

Re: Xantrex XW, Generator not being qualified until load applied to generator

Be sure you get a motor RUN cap, not a starting cap. A starting cap will last 10 - 15 minutes, then goes boom.

BB. wrote: »

I wonder how you know that factoid? :D

-Bill "duck and cover" B.

High school electronics lab. On my way out the door, 10 min into the next lecture..... and I've heard it smells real bad ! outlet under the last bench - always an empty bench.

Xantrex XW, Generator not being qualified until load applied to generator

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