genset alternator failure

unicornio
unicornio Solar Expert Posts: 217 ✭✭
in Off Grid Solar & Battery Systems #1
hi, there,

today my genset is broken ... only has a little over half the output voltage (160v instead of 230) ... this is a soundproof 5.5 kvas diesel genset, a very common model, made in China and Yanmar engine (copied, i think) that I've noticed a couple of breakdowns ... the alternator is brushed and with AVR ...

tomorrow I'll get to check it ... if anyone can help me or guide me a bit to resolve this fault I would appreciate ...

Thanks in advance! ...
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: genset alternator failure

    Very sorry to hear that... Can't help other than suggest looking for broken/loose/burned wiring in the generator, voltage control, output wiring.

    Is the generator running at speed, or too slow?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    #3
    Re: genset alternator failure

    I'm assuming the generator is a 230V 50 Hz European unit, and that the engine is operating at normal rpm. The first thing to check is the stator. You could have a breakdown on the insulation on the stator windings (from overheat) causing it to short, and hence not use the portion of the windings from the shorted point to the end or start leads, causing low voltage. The stator is easily checked with an ohm meter.

    The second thing to check is the rotor winding - check it at the slip rings for continuity and proper resistance, and no shorts to the rotor shaft.

    If the stator and rotor checks fine, then you have either a bad AVR or brushes.
    --
    Chris
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #4
    Re: genset alternator failure

    many thanks for your answers ...

    apparently rotates at a normal rate (3000 rpm), and is giving 45/47 Hz but only 160/170 volts at the output ... I was charging my batteries with vfx3024E with a load of about 2.3 kw, all normal... and suddenly vfx has been disconnected the AC input and mate3 show low AC voltage alarm...

    I think that could be a problem of brushes, because it came with a spare set of brushes that seems a little suspicious, no? ... hehehehe

    in 5 years, has only 276 hours working, and at least I will have spent another 50 or 60 hours solving wiring faults, connectors ... is a bad chinese product that leaks fuel and oil ... a disaster of product, but they are very cheap, and that then always have to pay after! ...;-)

    I take note of your suggestions, tomorrow I'll get to work and makes all the checks ... i back here and I will tell what i find ... i hope i can resolve it because I need it now that the weather is getting cloudy ...
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  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    #5
    Re: genset alternator failure

    For reliable off-grid power a conventional wound field generator can be fixed with baling wire, duct tape and a screwdriver. I've seen Honda EU3000's smoke a phase in the three-phase permanent magnet generator they got built into the flywheel before. Talk about a nightmare to fix!
    --
    Chris
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  • Ken Marsh
    Ken Marsh Solar Expert Posts: 114 ✭✭✭✭
    #6
    Re: genset alternator failure

    I do not understand some of your terminology but-
    could your charger have just disconnected and you are measuring unloaded voltage?
    Unloaded voltage on the old brushed gen sets can be anything and is commonly low.
    Also, if frequency is low, that can only mean that motor speed is low.
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #7
    Re: genset alternator failure
    Ken Marsh wrote: »
    I do not understand some of your terminology but-
    could your charger have just disconnected and you are measuring unloaded voltage?
    Unloaded voltage on the old brushed gen sets can be anything and is commonly low.
    Also, if frequency is low, that can only mean that motor speed is low.

    I wish I could explain everything better in English, please tell me if something is not well written or not clear ... many thanks you guys for your help!...;-)


    here are some pics of the genset model, and too, pics of this work:
    hyundai silent diesel genset dhy6000se

    tests and results:
    the breakdown was produced in the same way with any load, (and without any load) and I testing it with air heater 2000w, same thing happened, so this ruled out any fault in the external whole system, nor in the inverter (charger)...

    I've been checking around for a few hours ... as a "soundproof" genset (makes a deafening noise anyway) cost me a lot undress and access inside ...
    (has been a very fun Sunday day and I've been very busy! ...)

    worst of the fault is that when I turn on the genset all works well, is after about 10 minutes when the fault starts, lowering the output voltage and the frequency that reaches 45Hz (beyond the limits of the manufacturer), and when I stop ... and start it again recurs to the same failure in the same time...

    This gave me the clue (like Ken Marsh say) that could be a mechanical problem, fuel supply or something wrong with the diesel engine control ...

    by the way I found several loose screws, one of them had fallen on the rectifier bridge thats are in the alternator ... thanks to the faston terminals of the diode bridge were isolated, if not maybe i would have a fire! ... this screw in addition to fix a power strip, also connected to ground the wire from the bridge rectifier negative output ... I connected everything as it should be, and have rejoiced because I thought I had solved the breakdown ... but not!, the fault was still...:-(

    I think this rectifier is responsible for generating the DC voltage used to charge the battery, powers the 12V auxiliary output and also (and this is more important), I think it will also be to produce the excitation voltage going to the brushes of the alternator (handled by avr, of course) but I'm not sure all this, I have not the schematic diagram, so everything is guesswork ... anyway the voltage of 12V auxiliary output and battery charger had checked and work well. .. even with the negative lead of the diode bridge down? ... how strange! ...

    Then I removed the control panel where the cables are very short and tight (the savings from Chinese) and I left a little better, I've lengthened some wires and replaced a faston multiconnector by some other connector with much better quality ...

    I tried to mount it all over again, and apparently everything is resolved!!!
    but tomorrow will rain all day, and I'll have to try it to work, to make sure all is ok ...

    I feel that the post is so long ... but it's the story of a nightmare! ... so I hope to written well in English all I think ...;-)

    thank you very much for your suggestions ... I'm pretty discouraged because I know if something has been fixed itself, it can re-break itself again ...meanwhile I learned a lot about this genset, and although I think it is very poorly assembled, but the design is outstanding and the truth is that you have to remove many things, but at least all are easily removable and can be to re-assemble well! ... hehehehe
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  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    #8
    Re: genset alternator failure
    unicornio wrote: »
    I know if something has been fixed itself, it can re-break itself again

    Those are words of wisdom that should be etched in stone ;)
    --
    Chris
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #9
    Re: genset alternator failure
    ChrisOlson wrote: »
    Those are words of wisdom that should be etched in stone ;)
    --
    Chris

    yeah!...In Spain we have a mantra: what is fixed without the help of human hands, can break down again, even with nor without the help (of the human hand)... ;-)))

    but allways, I'm too old and I'm already accustomed to stay without knowing why something works again without having repaired ...hehehe
    so as long as something works, you better not touch it! ... ;-)
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #10
    Re: genset alternator failure

    Rectifiers for charger and field winding are likely different. They need their heat sinking.
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #11
    Re: genset alternator failure

    my genset still does not work, I've removed dozens of times and have found that i have only a little knowledge about electric generators ... today is a holiday (and my birthday), so today I could not locate service parts ... i believe now that avr broken, but I'm still checking other things ...
    RCinFLA wrote: »
    Rectifiers for charger and field winding are likely different. They need their heat sinking.

    i only find a brigde rectifier in this alternator...how many diodes more i can find in it?...
    if anyone has wiring diagrams and/or test procedures for this type of generator, 6kvas, with brushes and avr, any link, any info I would appreciate very much ...

    what is certain is that I hope to learn enough to be able to do something good with this generator, really so bad (the yanmar type diesel engine works like a charm, start and runs ok, except for some oil and fuel leaks) ... I think the control and protection circuits that are the biggest problem is, but not know if it is possible to couple it to the other generator avr circuit, if there is compatibility in this case or has to be specifically designed one for each other??? ...

    meanwhile I'm working with a 30/40% of SOC, something I never had done to my batteries, I hope i can recover it well and get it to work a few more years ...

    thank you very much to all for your help guys!!!...;-)
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  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    #12
    Re: genset alternator failure

    unicornio, a rotating field AC generator is the simplest thing there is. It has a rectified exciter winding that is used to feed the field. The AVR simply varies the amount of DC power going to the field in the rotor winding by sensing the AC voltage from the stator winding, and adjusting it as necessary. The stronger the field (from the AVR increasing field voltage and current), the higher the voltage from the stator will be. Low field power will cause low voltage.

    You can actually excite one of those externally from the starting battery with a variable resistor in an emergency with a totally failed AVR, if you have a constant load on the generator. I've done it before.
    --
    Chris
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #13
    Re: genset alternator failure
    ChrisOlson wrote: »
    unicornio, a rotating field AC generator is the simplest thing there is. It has a rectified exciter winding that is used to feed the field. The AVR simply varies the amount of DC power going to the field in the rotor winding by sensing the AC voltage from the stator winding, and adjusting it as necessary. The stronger the field (from the AVR increasing field voltage and current), the higher the voltage from the stator will be. Low field power will cause low voltage.

    You can actually excite one of those externally from the starting battery with a variable resistor in an emergency with a totally failed AVR, if you have a constant load on the generator. I've done it before.
    --
    Chris

    hi, Cris!...many thanks!...maybe you can draw with hand a simplest diagram?...I have many laboratory power supplies, I think I can generate virtually any dc voltage with what I could do some tests ... at first I want to do a full battery charge and would not mind being there varying load to maintain the voltage ... will almost continuously from 2.3 kw (vfx3024e 85a charger) until absorption, and I'll have to do a good EQ also ...

    remember I found a bridge rectifier with a loose cable, but it seems that this does not affect anything ... I have found that only serves to generate a 12V auxiliary voltage (something that has always seemed very odd) have almost all genset "small "or portable ...

    then I have only seen the AVR, and I have not found more semiconductors that could check ...

    where you say you have to put him the dc voltage at the brushes? ... tell me! ...;-)

    look like in the end I will learn! ... hehehehe
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #14
    Re: genset alternator failure

    The problem with testing is that necessarily I have to mount the metal panels and exhaust system (two mufflers) to pass gas out ... look at the photo and see: if I have the sight generator running the exhaust give me across the face! ... hehehehe

    https://picasaweb.google.com/lh/photo/Z8R3b8fVeHUxjBG7B03p-NMTjNZETYmyPJy0liipFm0?feat=directlink
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #15
    Re: genset alternator failure

    Try this http://www.youtube.com/watch?v=wdiGEKilc5Q and try their web site. http://www.youtube.com/user/AuroraGenerators more videos. The one he's working on looks like yours. I did not see the diode stack, ring or whatever they use, could be built into the AVR ??. Low voltage is usually a Diode problem depending on the poles there 2,4,6 or more of them.

    http://www.auroragenerators.com/
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  • KeithWHare
    KeithWHare Solar Expert Posts: 140 ✭✭✭
    #16
    Re: genset alternator failure
    unicornio wrote: »
    hi, there,

    today my genset is broken ... only has a little over half the output voltage (160v instead of 230) ...

    I have a 10KW Briggs & Stratton running on Propane. I had a similar issue about 18 months ago -- 160V instead of 240V. On my genset, in the voltage regulation circuit, there are two large capacitors, one of which had spilled its guts. We replaced both of the capacitors (because if one blew, the other one might blow soon), which fixed the problem.

    Keith
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #17
    Re: genset alternator failure
    Blackcherry04 wrote: »
    Try this http://www.youtube.com/watch?v=wdiGEKilc5Q and try their web site. http://www.youtube.com/user/AuroraGenerators more videos. The one he's working on looks like yours. I did not see the diode stack, ring or whatever they use, could be built into the AVR ??. Low voltage is usually a Diode problem depending on the poles there 2,4,6 or more of them.

    http://www.auroragenerators.com/

    thank you very much! ... yeah!...i think is the same, and have some information ... I'm going to try to learn how all this works ...;-)
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #18
    Re: genset alternator failure
    unicornio wrote: »
    thank you very much! ... yeah!...i think is the same, and have some information ... I'm going to try to learn how all this works ...;-)
    I'd look close at the brushes and slip rings for them. I had a Kohler that had them before they went brushless and they were a problem from time to time. They would get crappy and the springs would lose pressure on the brush.

    It sounded like that company had parts for them, I am sure you can get them over there. You might be able to get in touch and pick their brain some. The issue without knowing the exact problem is you can spend a lot of money trying to find it.
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  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    #19
    Re: genset alternator failure
    unicornio wrote: »
    hi, Cris!...many thanks!...maybe you can draw with hand a simplest diagram?...I have many laboratory power supplies, I think I can generate virtually any dc voltage with what I could do some tests ...

    Well, before I try to make one of my scribble drawings, check this - if you check the brushes with an ohm meter one should go to ground and the other supplies DC + to the field. You can hook up your DC power supply to those wires coming from the brushes and slowly increase the voltage to the field while monitoring the AC output voltage of the generator. This works in a emergency to manually excite the field so you can charge your bank. I've just hooked some jumper wires up to the starting battery on a genset before and use the battery power with a rheostat (variable resistor) to set the field.

    That will also verify that it's a problem in the field exciter circuit (or AVR).

    Looks your generator has a built-in hair dryer with that exhaust arrangement ;)
    --
    Chris
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #20
    Re: genset alternator failure
    ChrisOlson wrote: »
    Well, before I try to make one of my scribble drawings, check this - if you check the brushes with an ohm meter one should go to ground and the other supplies DC + to the field. You can hook up your DC power supply to those wires coming from the brushes and slowly increase the voltage to the field while monitoring the AC output voltage of the generator. This works in a emergency to manually excite the field so you can charge your bank. I've just hooked some jumper wires up to the starting battery on a genset before and use the battery power with a rheostat (variable resistor) to set the field.

    That will also verify that it's a problem in the field exciter circuit (or AVR).

    ok, Cris!...tomorrow I will do this test with an adjustable power supply, ... how many amps will I need to drive the field? ... anyway so I can regulate the output voltage well, i can charge mi battery ... I also test if the avr is not working, and already i know I have to change ...
    also I have to find an avr in these very small villages! ... hehehehe
    i think any avr for 50Hz/220V/5kva/brush can work for my genset...is ok?...

    very good point, Cris! ... thank you very much! ...;-)
    ChrisOlson wrote: »
    Looks your generator has a built-in hair dryer with that exhaust arrangement ;)
    --
    Chris

    hehehehe...shure, with this air dryer i can get the hair and face like michael jackson in "thriller" video!...;-)
    back here tomorrow, I hope to be lucky ...thanks so much!...;-)
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  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    #21
    Re: genset alternator failure

    The field current is very low - about 0.1-0.2 amps. If you check the rotor at the slip rings for resistance you should see (typically) around 60 ohms thru the two coils. The regulation voltage at the brushes is typically around 10.0 volts with no load on the generator.
    --
    Chris
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #22
    Re: genset alternator failure
    ChrisOlson wrote: »
    The field current is very low - about 0.1-0.2 amps. If you check the rotor at the slip rings for resistance you should see (typically) around 60 ohms thru the two coils. The regulation voltage at the brushes is typically around 10.0 volts with no load on the generator.
    --
    Chris

    ok, Cris...now is morning here, i will make this "invent" and i will come back here!...;-)
    many thanks!...
    KeithWHare wrote: »
    I have a 10KW Briggs & Stratton running on Propane. I had a similar issue about 18 months ago -- 160V instead of 240V. On my genset, in the voltage regulation circuit, there are two large capacitors, one of which had spilled its guts. We replaced both of the capacitors (because if one blew, the other one might blow soon), which fixed the problem.

    hi Keith!...many thanks for your help...;-)
    You can look at my AVR, is sealed with polyester resin as it was in the 70s so that nobody could copy your circuits! .... hehehehe
    and too, no longer could repair them! ...

    https://picasaweb.google.com/lh/photo/wypBwcA2N1yjvbzTtd0JZ9MTjNZETYmyPJy0liipFm0?feat=directlink

    (as a good example of bad industrial policy!) ... are things not to buy? ... I will try to locate a AVR that make someone is honest and that works well, and I will giveit to my genset by her birthday! .... hehehehehe

    I think I'll stick with the good of this generator:

    the engine leaks oil and fuel ... but it works very well and starts to the first, I can take the losses? ... it is a classic engine (yanmar) very marketed, that has a lot of spare parts and a lot of literature that has been used ...

    the alternator is copper? ... I have heard that some Chinese generators already bring the windings with aluminum wire? ... I will withdraw all electronic controls that fail and I will put a quality controller that is now making redundant functions: the deepsea 3110, that was recommended by my friend Stephendv ...

    If I get (reversing time) to tame it and get well functioning, for the little that I use and I can take all that I have to live! ... hehehehe
    maybe I can tune with him and can "find" a glad machine, and once removed all the bad devices, it can become a noble and trustworthy stand-by AC system? ...;-)))))
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #23
    Re: genset alternator failure

    how to use a generator with AVR damaged in an emergency situation??? ...

    thanks to the synergy of the forums, and especially to CrisOlson, I learned a little about the operation of electric generators! ... am very happy and indeed, as always, now i look the generators with a different eyes! .. hehehehe ..

    once understood what Chris told me, I just started to get testing to get charge my batteries for a week with cloudy sky ...

    although the magnitudes changed much, I had enough confidence in myself to deepen and see how everything was working ... also I did a bit of surfing on google to get more information about AVR's...

    effectively introducing a DC voltage by connecting to the brushes, the generator started giving its output voltage ... but I had to get up to 100V@1A to getting 3.4 kw or so without the voltage down to 220v...

    the problem was that the power supply had to feed (itself) of the same voltage coming out of the generator, since OB VFX being bidirectional design, the inverter can not work (logically) when it are charging ...
    That raises the question of whether the generator takes a low voltage the power supply malfunctions out of its limits, lowering the voltage of the brushes, producing a voltage drop spiral ... lol
    in the other hand, if the power supply is giving a very high voltage to the generator working without load, the output voltage of the generator will be so high that it would burn the power supply...

    with some care, i go regulating output of the both power suplies until I got the balance (I had to put two power supplies (of my collection ;-) in series to achieve reach that voltage with 1 amp current) ... this phase gives a little scary, so I shut off power throughout the facility and isolate the genset and VFX, all else off! ...had to make sure not to burn the fridge, TV and all other appliances of houses of the farm!... hehehehe ... luckily OB VFX has a large margin (generous) and working up to 300V AC at its input and that's what calmed me! ...

    I put some pictures of the operation ...

    Attachment not found.
    Early tests with a single power supply...
    curiously voltage has some diabolical aspects...lol


    Attachment not found.
    the connection to brushes, the AVR is disconnected...


    Attachment not found.
    dual power supplies in series gave me all the power I needed, (3,4kw or so) so I think it would have to put 100 or 110 volts DC to have 6kw ? ...

    I have seen some information on AVR that work giving 120v @ 3amps to brushes... this'll have to find out when I get my new avr, which I hope will be of higher quality and longer working ...

    I sincerely thank you all, and especially to CrisOlson, your help in this issue! ...
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  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    #24
    Re: genset alternator failure

    They must have the rotor coils wound really weak in that generator. I've been able to get them going in the past with just about 10 volts off the battery directly to the brushes, and very little amps. To get closer to rated power it typically takes up to 70 volts, and then the field winding will pull more amps. 120 volts and 3 amps to the rotor is scary ;)

    --
    Chris
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #25
    Re: genset alternator failure
    ChrisOlson wrote: »
    They must have the rotor coils wound really weak in that generator. I've been able to get them going in the past with just about 10 volts off the battery directly to the brushes, and very little amps. To get closer to rated power it typically takes up to 70 volts, and then the field winding will pull more amps. 120 volts and 3 amps to the rotor is scary ;)

    can it be? ... think I'll have to check everything ???... the resistance of the windings I remember that was right ... I will go look tomorrow ... and especially when i have the new avr i can to confirm ...
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #26
    Re: genset alternator failure
    ChrisOlson wrote: »
    They must have the rotor coils wound really weak in that generator. I've been able to get them going in the past with just about 10 volts off the battery directly to the brushes, and very little amps. To get closer to rated power it typically takes up to 70 volts, and then the field winding will pull more amps. 120 volts and 3 amps to the rotor is scary ;)

    really do not like nothing that is happening ... maybe you're right that there is something else out there failing ... :-(

    for more volts that I put it, not to get more than 2kw 204V ... will I get the new avr on Monday, and then I can prove how it going and if the whole thing finally works ...the avr that have 120v@3a maybe was an AVR for general purpose, adjustable and maybe it was for more powerful generators ... I finally i choice to buy the original manufacturer (Chinese) so I hope to have more luck and last me more than 200 hours ...

    I'll tell you! ...;-)
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #27
    Re: genset alternator failure

    Today I got a new AVR circuit and my genset apparently is working perfectly ... I have not yet measured the operating voltages, but I'll measure it to know how it works,... but probably I will not have to do odd jobs anymore because I have avr bought two to be forewarned! ....

    thank you very much to all for your contributions! ...
    and this thread is "happily" closed!
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #28
    Re: genset alternator failure

    Glad to hear it's finally working! Seems like it took a long time to get the AVR, how much did they charge if you don't mind me asking?
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #29
    Re: genset alternator failure

    Hi, Stephen!...

    i am glad to see you too!...thank you very much for your solidarity and compassion! .... hehehehe
    you know the bad season we have here now, after two years without a cloud, has been very unlucky for my batteries! .... lol

    but i am very old and now the problems make me horny! ... hehehehe

    it cost me 55 euros (plus 21 % new VAT, is dreadful) and I bought two, total almost 150 euros ... I finally found a good supplier of spare parts for Chinese generators here in Spain, so during this energy crisis I have learned a lot about solve these so bad genset problems, and so I hope to keep myself it working many years to come! ...;-)

    cheers!...;-)
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #30
    Re: genset alternator failure

    55 euros is not too bad. What would worry me more is the time it took to get it!

    PS. you probably mean "excited" instead of "horny".... although maybe it gets lonely out there in the mountains of gredos and the only thing keeping you company is a nice sexy chinese diesel, mmmmmmm.

    ;)
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #31
    Re: genset alternator failure

    stephen,
    it was a reference to the horn on the unicorn otherwise i might've been tempted to snip it.
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