Generator still not being qualified on XW

Les Nagy
Les Nagy Solar Expert Posts: 121 ✭✭
in Off Grid Solar & Battery Systems #1
I originally posted the problem in this thread:
http://forum.solar-electric.com/showthread.php?t=8732

I thought I would start a new thread with updated information for the sake of readability.

My original problem is that a KIPOR KGE 2500 X I purchased will not qualify on my Xantrex XW4548 unless I supply a specific load to the generator during the qualification time. If I run a microwave oven on it it it gets qualified as a good AC source after 45 seconds.

I looked at the wave form with an oscilloscope and found a generally right looking AC waveform but it had a 1.4KHz or so ripple of around 10V peat to peak. Connecting a 500W or 1000W resistive load kills the 1.4KHz component but it makes the waveform go far from a sine wave and it does not get qualified.

The only way for me to get the generator the generator online is to set my distribution system to bypass so that the generator is feeding the house directly, start up the microwave until the XW switched over, shut off the microwave and then switch the distribution system back to run off the inverter. Once the XW is running the generator through and charging my batteries I can vary the load all over the place and unless the generator gets overloaded all is fine.

The suggestions in the original thread was that perhaps a motor run capacitor of 1 microfarad to some higher lever would do the trick. Well I finally found motor run capacitors here in Chile and purchased three 1 microfarad capacitors. One did not help, and three did not help (in parallel). Sure enough the caps. kill the 1.4KHz component but really make a bigger mess of the waveform.

So it seems that the KIPOR generator I have is not well suited to this setup, and I am probably lucky to get it to qualify at all with microwave trick.

Any suggestions other than buying an IOTA systems charger to charge the batteries directly from the generator? It is such a pain to be running around switching things around just to get the generator online with the XW. Perhaps someone knows how to force the XW to accept an AC source regardless of the perceived quality of the source?
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: Generator still not being qualified on XW

    I am guessing, but I believe that the inverter/chargers are actually running the generator power "backwards" through the inverter to charge the battery bank...

    If the generator waveform is not sinusoidal enough (poor shape, other frequencies imposed on the sine wave, out of frequency tolerance range, etc.)--The inverter may simply not be able to properly take the input wave form and pump it as DC back to the battery bank.

    I don't think a resonant transformer is the answer (probably would create even more problems). If you could borrow an isolation transformer--perhaps that would help (filter some of the non-linear noise)... But that is probably a long shot.

    Have you tried talking the generator representative (or perhaps a very knowledgeable generator repair person) and see if what you are describing could be the result of a "broken" voltage regulator (or regulator connections). If the genset uses brushes for the field windings--I would pull them out and see that they are not broken and that the slip rings are smooth.

    -Bill :confused: B.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #3
    Re: Generator still not being qualified on XW

    bb,
    what do you think of making a series resonant circuit across the hot and neutral tuned to 1.4khz to short out that frequency only?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    Re: Generator still not being qualified on XW

    I am real leery of attempting to use brute force to short out the non-fundamental sine wave frequencies on a high power system...

    It will probably increase current flow in the generator (and possibly overheating).

    Plus the energy needs to be dissipated (low Q value) or else you may have just created another tank circuit (another tuned resonance and cause other problems).

    If there is a problem with the voltage regulator--It could be "injecting" noise through the field windings into the main generator windings.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Les Nagy
    Les Nagy Solar Expert Posts: 121 ✭✭
    #5
    Re: Generator still not being qualified on XW

    I agree. Trying to tame a specific frequency in a high power system is asking for trouble. The fact that the waveform changes to a worse one with the capacitors connected shows it is not going to help.

    A Pi or T filter inline with the generator might work but again the generator does not seems to stay clean with reactive loads. Even with a resistive load the waveform gets bad, such as with halogen lamps.

    The XW will keep running the generator once it is qualified even when the waveform is not right so I don't think anything is wrong with the generator but I could be wrong.

    As far as trying to find someone here who is knowledgeable with anything is a crap shoot. In Chile, almost everyone lies about their capabilities and it would be more risky to have some random person here who is supposed to be an expert touch this than me throwing rocks at the generator hoping to fix the problem.

    I did try an autotransformer and it did not clean things up. Ironically I have another 120V generator that I used for a bit through the autotransformer and the waveform was really bad, but the XW qualified it anyway.

    I guess I will poke around a bit more and see what I can figure out. Thanks for the ideas and support.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #6
    Re: Generator still not being qualified on XW

    You may need to get in there and figure out the regulator circuit (active, passive, etc.)...

    Here is one guy that just had a bad capacitor in his passive regulator--Caused his voltage to sag under load. He drove his genset to the factory and they jumped right out there and diagnosed the problem (it is a nice dream anyway. :D)

    Also, on that same page, lots of neat O'scope pictures so people can see the different current waveforms that can be caused by different loads... And why "bad power factor (PF<0.9) is difficult to explain without pictures.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #7
    Re: Generator still not being qualified on XW

    Are you sure it's not just the voltage of the gen which is outside of the XW's settings?
    Have you tried adjusting the acceptable voltage and frequency of the XW to be more forgiving?
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  • Les Nagy
    Les Nagy Solar Expert Posts: 121 ✭✭
    #8
    Re: Generator still not being qualified on XW
    stephendv wrote: »
    Are you sure it's not just the voltage of the gen which is outside of the XW's settings?
    Have you tried adjusting the acceptable voltage and frequency of the XW to be more forgiving?

    Yes of course. The frequency is a solid 51Hz and the voltage is a steady 225 volts. I have set the limits on the XW to 48-60HZ and the voltage to 160-280V. I see though now with the XWConfig software that there is a setting for XW to Gen Transfer Delay Time and it is set to 655.35 "seconds". I doubt that the units or the value of that setting can be right. 65535 is a binary 11111111 so it appears that someone messed up on a value conversion somewhere. Anyone know what this value is?
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #9
    Re: Generator still not being qualified on XW

    Didn't mean to be patronizing, it always helps to make sure the basics are covered :D

    I can't find that value in the xwconfig manual, but anyway, can you change it to something more reasonable and see if it fixes the issue? "Seconds" seems like a reasonable unit to use - guess it's meant to be used as a generator warm up time, before putting the gen under load.
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,891 ✭✭✭✭✭✭
    #10
    Re: Generator still not being qualified on XW

    Sounds like firmware should be checked. With serial number+ firmware and build#, that info is under device info on the system controll panel, call xantrex and see what gives. No whining about expensive phone calls unless you really like this thread.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • Les Nagy
    Les Nagy Solar Expert Posts: 121 ✭✭
    #11
    Re: Generator still not being qualified on XW
    stephendv wrote: »
    Didn't mean to be patronizing, it always helps to make sure the basics are covered :D.

    It didn't come across that way and I hope I didn't come across as annoyed! Text is such a bad conveyor of emotion. The 6553.35 seconds is a long time for a wait, almost 2 hrs, so I believe that the wrong value or wrong unit is being displayed.

    Dave:

    I have already made some inquiries with Xantrex earlier about this and my firmware is all up to date.

    I am not afraid of phone calls as I use Skype. :D I will contact Xantrex and ask them about the value in this field.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #12
    Re: Generator still not being qualified on XW

    Yea, sounds like a software feature (aka bug)... Many times, folks use the first bit as a negative value/flag--May have been intended as "function disabled" flag for other parts of the software and got displayed via a generic routine.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,891 ✭✭✭✭✭✭
    #13
    Re: Generator still not being qualified on XW

    Les, no worries about how you are percieved! I remember firmware fixed a gen problem for a customer. I just fo not remember the situation... If your xw is fairly new (and the manufacture date is known by you) you should not have an xw problem but rather, as you know the generator. Most all of the bug's are fixed now. Good Luck
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • PhilS
    PhilS Solar Expert Posts: 370 ✭✭✭
    #14
    Re: Generator still not being qualified on XW

    Les,

    For years my Xantrex SW2512MC wouldn't "hook up" with my 10KW generator unless there was another load applied first.

    It was no problem as usually when the generator was running, it was on so that I could pump the well into a holding tank. As soon as I started the well, the Xantrex would then accept the voltage and start charging batteries.

    My well pump broke and I replaced it with a Grundfos pump that now runs off of that same Xantrex and doesn't need the generator.

    And then ... I had no way to load the generator so the Xantrex would start charging. Before, even if I didn't need to run the pump, I'd start it for a minute to get the Xantrex started charging.

    I finally installed another charger (an old 20a/40a/100a automotive "charger/starter"). It connects directly to the generator and is set to "20 amps, continuous". As soon as the generator starts now, that charger starts sending 20a to the batteries and the Xantrex starts charging about 30 seconds later.

    It sounds, from what you've described, that my solution may also work in your situation since your inverter/charger "hooks up" when you run the microwave.

    Phil
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,022 ✭✭✭✭
    #15
    Re: Generator still not being qualified on XW

    Phil,
    Your work-around sounds like mine. I didn't do it because of no generator pickup, but to maximize the 10kw genset usage. It's a Vulcan 100amp 48vdc industrial charger (never seen more than 80 amps) and my Surrette 20 hour rate is 840ahr..c10 is 84 amps. If Vulcan and Xantrex 4048 are started at the same time then the charge rate on the Xantrex is 1, then moved up as the Vulcan drops down (single rate charge...as voltage rises amps decrease). This is monitored by an ac clamp meter on the genset feed. Works well, but requires attention.

    I now have a load service again (after 6 years off grid) so a charge is usually from 9pm to 7am (off peak) at 10amps max charge from the Xantrex only. Lots cheaper than diesel unless you consider the monthly charges :blush:

    Ralph
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