How to test your Electricity Generator's AVR, Brushes and Alternator on a Brushed Alternator

[@Generatorguru]

We thank you for your interest in our help videos. Unfortunately, due to limitations in KZbins comment sections, we are unable to quickly answer questions in the comments. Please feel free to contact us directly here: www.generatorguru.com/need-help/ PLEASE NOTE: You cannot test the AVR without a very expensive piece of kit called a Megga meter. This is why you need to do these tests to make sure there is no other problems in the Alternator. This will discount any other problems leaving the only possibility being the AVR.

[@phantomwalker8251]

you need to show,or tell,what happens when certain items blow. . my geni reved up. trying to find out why. the shop said,its chinese,buy another. there not interested. its remote start,key,pull,3.500 w. inverter. i have an old subaru,10 yrs,still going,but noisy as hell. 5kva. need a more portable geni. so bought the inverter.small suitcase size.

[@CodyJohnson-or1sl]

I have never commented on any of the hundreds (if not thousands) of KZbin videos I've watched, but I am beyond grateful for this. I promised a client of mine that I would fix his generator, which I've never done before. More than 5 hours and many YT videos later, I still hadn't figured out the issue. The brushes were shot, everything else had continuity. Replaced the brushes, but still no power. You are the ONLY person I found that pointed out that the positive wire always goes on the left side of the brushes. I just hooked them up how they were before (another shop tried to repair). All of a sudden, IT WORKED!!! So, thank you so much for your help. Very grateful for you.

[@bunnyman6321]

💯

[@Generatorguru]

I am so glad we could help! If you need any other info we have an interactive help centre which can help you fix most generator issues: generatorguru.com/need-help/>Engineering

[@rreatery1960]

Thank you a thousand times!! You were very instructive in every phase of showing how to properly troubleshoot a generator. You even took the time to show the proper settings on the multimeter for anyone who needed help. Your a blessing. GOD bless you.

[@todaywefly4370]

I find it interesting that people who really understand what they are doing make great simple instructors. No complicated garble that the watcher doesn’t understand anyway.

[@Generatorguru]

Thanks! *blush

[@daleslover2771]

Generator Guru back in the early 70s, I was taught by my grandfather, how to rebuild generators, alternators and starters, with the simplest tools available, close to 50 years I've only had to replace one generator to an alternator, switching over a 1960 Ford F-100 Excellent video, really enjoyed it.

[@Generatorguru]

Hi Dale Thank you for the comment, I would love to hear more about it, a lot of people get stuck with the lesser known or unbranded generators as many rewind companies do not want to touch them so charge high prices for repairs to push people away and many people find themselves with a unit that is no use to anyone but not worth the repair costs

[@bungalowfeuhler1541]

Thank you so much! This video saved me weeks of ordering parts, dropping them in and finding out they didn’t fix it. You are the best!

[@engineeringdept.generatorg1760]

Thank you so much for your Comment! I have patted my team on the back and passed your thoughtful thanks onto them. We really appreciate you letting us know. Would you be able to leave a review for us on trustpilot? We have recently signed up with them and would like to spread the word and help save more Generators. If you could be so kind, please leave a review via this page uk.trustpilot.com/review/generatorguru.com Thanks again for your feedback!!

[@agentnuget]

this is actually helpful. every other video I've been finding requires jumper cables to test the AVR. didn't think about testing the generator itself.

[@bapao83]

Straight to the point and a very good guide for generator troubleshooting. You have earned a sub!

[@michaelwest2608]

Thank You! Finally a video on fixing a generator with brushes that makes sense. I am finally now able to narrow down what the actual problem is. It is the AVR. Thank you again for the awesome video.

[@garyrancilio7184]

This has been the best instructional video I have found on you tube. Thank you for taking the time to demonstrate the testing. Now I have a question not really covered. I have 4.7 v to both the R1R2 and L1 L2 and 0v on R1L1 but I only am getting 1.7v across the brushes. The surface that the brushes are riding on are smooth. I thought these were grooved. I am looking forward to your expertise on this. Gary

[@Generatorguru]

Thanks for the feedback! R1 and L1 should be 0 vac if you have a voltage changeover switch and set it to the lowest setting. These results indicate you need a new AVR. The AVR should bring up the rotor to 5vac also if you run it for 20 mins without load to stabilize the magnetic field. Your brushes will be smooth where they connect to the rotor, but be sure they have enough play in them to make a good connection. If you are still having any trouble please let us know and we will be happy to advise you further. :)

[@garyrancilio7184]

Sorry I should have added that I have already replaced the AVR. This unit has only been used a short time. brushes are not even worn in yet.So are you saying I should run it 20 minutes with the new AVR? one last question. This John Deere 6200 watt runs wide open all the time. Is that normal?

[@FUNFORALL105]

Generator Guru sir i changed the Generator AVR but the voltage is still not stable ..when i start some things on it becomes decreasing voltage from 220 to 195..

[@FUNFORALL105]

i think the AVR frequency is not set... how i set that frequency

[@joebodkin6534]

Followed your tests and ended up replacing AVR .Bingo, fixed it.$17 .Thanks

[@Generatorguru]

Nice work!

[@ovitvchannel]

Thanks brother.. Very well explained.. Great effort.. You saved my generator from selling lol

[@ovitvchannel]

Subscribed your channel 👍

[@mojavegold-]

Very good demo. Nice, clear explanation. I thought I might mention though - that the rotor is not "otherwise known as the stator". The part you call "the windings" are the stationary part of the generator - the stator. The rotating part of a generator or a motor is the rotor - whether it has windings, permanent magnets or a squirrel cage structure.

[@Generatorguru]

Hi Ralph Thanks for getting in touch! A few people have pointed it out over the years, a bit of a slip of the tongue we didn't spot until after we had posted the video, it used to have a little tag at that point in the video apologising but youtube seems to have dropped the captions off and won't let us replace them as its convinced they are still there!

[@Generatorguru]

The diodes on your rotor have blown. Check to see if they are accessible (usually on the end of the rotor or the fan end) if so replace them. If they are "in" the rotor you can take the rotor and windings to your local "motor rewind" company and they can rebuild it for you. But worth calling g a few companies as price varies greatly!

[@TheMills21]

Exactly what I needed and right to the point I wish 99% of the other instructional videos were like this one !

[@Generatorguru]

Aw! Thanks sop much!

[@floydie45]

Hi, Generator is outputting around 3.5- 4V on the brushes and 4 - 5 V on the L1, L2, R1, R2 and when I tested the L1 - R1 I was also getting 4 V but im only getting 8V on the 230V output on the generator. what could this error be?

[@hensonorr9343]

this is the first video i have seen on generators having a problem with mine and youre the best so far fully understand everything

[@Generatorguru]

Thank you for the feedback!

[@Generatorguru]

We DO want the test in volts (AC. v~). I keep getting emails saying otherwise, but we are doing a different test.

[@rasselas36]

Thank you for your excellent and most helpful video. I tested my Firman 4550/3650 and the results were not what I was hoping for. Across the brushes 13.28 L1/2 .38 R1/2 .34 and I didn’t bother measuring L1/R1. Please confirm my worst nightmare about this generator. Thank you again for sharing your time and knowledge.

[@Generatorguru]

Sorry! The rotor diode has blown. If you can see it on the end of the rotor you can remove and replace, or take it to a motor rewind shop and ask if they can change it for you. :)

[@rasselas36]

@@Generatorguru thank you. Have a merry Christmas.

[@crocodiledondii]

That was a very well explained and informative video. It removes some of the mystery about what's inside the alternator, and teaches the ordinary lamer some basic troubleshooting tips. Thank you.

[@Truthorshit]

nice one

[@jaygatz4529]

Hey man. Thank you. You made my day. I didn't loose magnetism, just had to change the avr (because i mistakenly connect the public power source to my generator. Turned the thing into a motor in a flash ruining my avr in the process. . That's a awesome guy you got there. (the black cutie) Thanks a lot

[@Ubique799]

Thank you, With your help I located the brushes on the Hyundai 7000 and cleaned them so it works again. Genpower were useless and argued over warranty times so much for the platinum warranty! Kind regards Andy

[@engineeringdept.generatorg1760]

Thank you for your feedback! We pride ourselves on "Good old-fashioned customer care!"We strive every day to save generators and other machinery from being scrapped due to parts not being available. It helps every-ones pockets and prevents tons of CO2 being added to our ecosystem!

[@roberttreadwell3252]

I had a loose terminal on a new duromax 8500 which fried the avr.. They sent a new one but it was only putting out 109 volts on both sides . The avr had an small adjusting screw and I turned it and adjusted it to 120 . Works perfect now.. Thanks for the video

[@Generatorguru]

Ummmm.... you should not be adjusting that screw! They are set at the factory and now you have just changed the hertz output!!! That is not good!!!!! IF IT HAD CORRECT VOLTAGE BEFORE THE AVR BLEW - Run the test in this video and follow relevant steps below. IF GENERATOR IS COMPLETELY BRAND NEW: Best to set it back to 109 then adjust the speed by the top screw on the carb. Use voltmeter to set to the correct voltage. Before you do that. be sure good fuel flow is coming from the tank as the Petcock has a filter behind it which might be blocked. IF GENERATOR HAS RUN FOR MORE THAN 1 HOUR: If you were getting low power and it is NOT totally brand new, but has some running time on it, this is what you need to check: 1) it needs servicing. (1st service best done at 50 hours as loads of metal shaving are produced as it settles in) - see kzbin.info/www/bejne/n6CkmHanhc2InMk 2) The engine has settled in and valves need resetting. This needs doing after about 1st 50 hours - see valve setting on our website and follow this video: kzbin.info/www/bejne/o4rVlaGGi9KUetU If you need more help please contact us on generatorguru.com/need-help/ and we can assign you an engineer. :)

[@roberttreadwell3252]

The generator is running at 60 to 61 hertz. This was tested with an Ideal sure tester

[@ulrichaustria7981]

I have the same problem 60Hz but voltage is good ​@@roberttreadwell3252

[@davids9139]

nice video. The only technicality I see is your explanation of a rotor and stator, two distinctly different parts. Keep up the great work! This was a very informative video!

[@Generatorguru]

Yeah I got nervous during filming. I did add a note over it on youtube, just after I uploaded the video, to say I got them mixed up but over the years it seems to have disappeared with all the updates that KZbin have done. Thanks for pointing it out. I will try to get that reinstated. :)

[@Moeterboater]

Hi, I've inspected everything and it all looks good. The generator is very new, used only a few times but it's been sitting in the shed for a few years. Does it sound like the AVR is gone? Would that horrible noise I described come from the generator if the AVR was gone?

[@markwestaway6173]

Hi, I have a 3KW Suntom single phase diesel generator. It was ok, but now only producing 85Volts AC. I have followed your instructions, I have 1 volt across brushes, brushes ok. 4.8 Volts on L1 L2. 4.9 Volts on R1 R2 0Volts R1 L1. Do I need a new Rotor?.

[@CerebralAilment]

What are the symptom of bad brushes? I recently replaced my AVR. I did not replace the brushes as the ones that came with the AVR seemed awful cheap. Now I'm curious if I should have replaced them anyways.

[@Generatorguru]

If you run the test on the Armature (Rotor) with the brushes fitted you should get a constant 5vac. If not replace the brushes. If you have any questions you can contact us via www.GeneratorGuru.com and we will pair you with an Engineer who will work through it with you. :)

[@ChubbyAnts]

Probably 1 of the most helpful and easy to understand videos I've seen. Especially as I'm trying to diagnose my genny which has stopped producing power. I've tried the drill technique and I've tried the flash with a battery after disconnecting the avr. Neither have worked. Tho the genny did produce power for the few seconds I flashed it with the battery. So now I'm wondering if the avr is fried as we noticed water in the extension lead that was plugged into it. So I'm thinking that has sorted out the avr to protect the alternator like you just mentioned it should!

[@Generatorguru]

For fault finding or technical advice, feel free to contact us using the link below www.generatorguru.com/need-help/ This will allow our engineers to review your query and give you the best possible advice!

[@satchmolips]

Hi, great video. I have a Generac 2500ff. Its putting out about 90 volts through the 240 outlet? (Can find the AV but not the brushes! Any advice please?

[@engineeringdept.generatorg1760]

Dear Geoff I would expect you to have a capacitor, not an AVR, in this case, can I please ask you to look at the video below www.generatorguru.com/help-me-fix-my-generator-repair-advice/ Run the test in the 1st video and let me know your results, please.

[@davidsalmon3605]

Very helpfull. I have a DG6, it looks like I have to remove the muffler first to access the end of the Alternator. Thanks for your help. David from NZ

[@Generatorguru]

If you have the super-silent version, You might be able to find the Capacitor (or AVR in some models) from the back panel held on by the 10mm bolts (some models only). If not you will have to remove the exhaust... sorry.

[@samgokuo1775]

I am very much curious, how much resistance reading is expected across the slip rings of the rotor, and does it vary, depending on the power rating of the generator? Very informative video by the way, thanks for the clear demonstration.

[@Generatorguru]

Thanks!! Resistance varies from generator to generator, and not all generator companies publish them. Hence needing a better way to test the alternators, and we came up with this! It is called the "Beagley Alternator Testing Technique" and was invented by our company founder many many years ago! :)

[@peterseviour]

Hi. Great video. Very informative. Im trying to repair a generator very similar to the 1 in the video. i think it is probably the avr but when i test the voltages with the avr disconnected i get 1-2 volts between L1 and R1. is that anything to be concerned about or not. all other voltages are 3-4 volts

[@malcolm4200]

Hi Thanks for the great Video, after following your great instructions I have come to the conclusion that my AVR is toast, I have an old Colman Powermate 5000 which i can no longer get parts for, my question is, can i fit a substitute of equal output ? thanks for any help.

[@Generatorguru]

Please contact our Engineers by submitting a ticket here: generatorguru.zendesk.com/hc/en-us We will assign you an Engineer to work through the issue with you. We do not charge for this service. :)

[@wilsonbrice2300]

Hi, I have a yamaha ef1000is that spins freely with the inverter unplugged but is like pulling molasses with it pluged in. I've also read that sometime was told it was the stator that was causing the resistance. what do you think?

[@engineeringdept.generatorg1760]

Dear Sir This is usually the stator on bigger framed generators, but on inverter generators, the stator very very rarely goes wrong, this is almost always the inverter at fault

[@wilsonbrice2300]

Styles Generator Guru bummer. thanks

[@doilHliob]

Thanks for the informative video. I am an experienced motorcycle mechanic, but wasn't sure what to look for in testing why my xp4400e generator was only producing 40 volts at the outlets. The tests you prescribed here showed all within normal operating parameters, is it your opinion that my AVR has quit? Thanks again!

[@Generatorguru]

Can you please clarify what the n v v u represent. Also which generator (make and model) do you have? Your rectifier is reading a bit high. I would suggest replacing it.

[@Generatorguru]

Was your voltage changeover switch on the lowest setting? If so you windings need replacing. L1 & R1 should = 0v ac

[@analiagamarra1715]

hi from argentina, your video was very helpful to me, you explain very well all the trobleshooting, thumb up for you, thanks

[@mtaylor191]

I appreciate your video I tested across the brushes and got 3.1 v, L1&L2 1.45v, R1&R2 .2 v, R1&L1 .2v. Any advice based on those readings

[@Generatorguru]

Please contact us on our website. We will assign you an engineer to run you through the next steps. generatorguru.com/need-help/

[@Generatorguru]

Does it have 2 poles on the windings (i.e. L1 and L2 And R1 and R2). If so then one of your windings sound like they have broken. Test the continuity on each set to see if one has snapped.

[@stephendullea5307]

What's that you say? Ahhh! Now I can hear you. I have to remember not to test my AVR on a windy day I guess...THANK YOU!! very content rich. Love that.

[@Generatorguru]

Stephen, Thanks for getting in touch. Yes, we find on some computers the sound works perfectly, and on others it is impossible to hear. If you have any questions please contact us www.generatorguru.com/need-help/. We have in planning stage, a new version of this video and a poster for step by step instructions. Thanks for your feedback! Hope it was helpful even with the sound quality. :)

[@atcaleb]

I get 94mv DC from brushes which move and look like new. It's a very steady 94mv too. I get 4.14V AC from tests #2 and #3. I get 0v AC from #4. Unit is 3 years old and only got used when new for a few hours. Looks exactly like the one you are working on. I did have it set to 110V like you said. I know AC from DC and I also had the + wire to brushes marked from the OEM. Is the left one too. The rotor assembly is USD $180. Is that the problem here from the info I am giving you? Rotor is clean and shiny. Very clean unit, stored inside. The brown wire(bottom nut) had a bit of rust and corrosion. Is clean now. Great video, only of it's kind!!

[@Generatorguru]

What are you getting in Volts AC on the brushes? In need this to tell you what the state of your rotor is. The other tests (on the windings) are good, so there is not problem there. Look forward to hearing from you.

[@enochsteven307]

Thanks a lot for all of the fault finding techniques. Really appreciate it. I have one query and here it is. What will be the likely conclusion if I don't get any reading(0 Volts) with the brushes and the windings??

[@engineeringdept.generatorg1760]

As your results are showing a low voltage, we suggest you “Flash” your alternator. Follow the steps below: 1. To re-excite your alternator, we suggest you only use this method, as described by Generac Generators on KZbin: kzbin.info/www/bejne/Y321Z2WpopyIibc 2. Run the generator for 20 minutes without load to stabilize the magnetic field in the Alternator. 3. Test with a suitable appliance to make sure the load is stable. If not go to step 4. 4. Repeat our tests: www.generatorguru.com/help-me-fix-my-generator-repair-advice/ If results are below 1 Vac, repeat step 1. If this continues please contact us. If results are between 1-7 Vac, but you are not getting full voltage at the sockets, then you will need to replace your AVR/Capacitor. If results are above 8-10 Vac range, then you will need to replace your AVR/Capacitor. But be warned that the high reading will damage the AVR/Capacitor over time. This could result in it lasting a fraction of the time expected on a stable alternator. If results are above 10 Vac range, be sure you removed the AVR/Capacitor before testing. If you have and are receiving this result, we suggest you take your generator to a “Motor Rewind” company for repair. You can find your local Motor Rewinding company by doing a search on the internet for “Motor Rewind.” It is worth asking for a quote from a few Motor Rewind companies as their prices can vary greatly.

[@juniortoigin3670]

Good nice explanation, can you please tell me this four wires coming out of avr. Which color wires for? (two blue, one white & one yellow wires)

[@Generatorguru]

Hmmm... Ok lets assign your issue to one of our engineers. Please contact them to set up a ticket on generatorguru.com/need-help/.

[@mrsamskey]

Thanks for the video. I tested my wurzburg W-8500 and got: 1) 4.4vac 2) 9.8vac 3) 8vac 4) 10vac. Any Idea what's up with my geni? Have you got a wiring diagram of the winding? Cheers. Sam

[@Generatorguru]

Please set up a ticket with our Engineers to discuss further. (We do not charge for this service.) www.generatorguru.com/need-help/

[@mickeycruz912]

Great video.. now I’m headed out to the shop to use what I just learned on a generator. Thank You

[@Generatorguru]

Glad we could help

[@AmberMarshArt]

hi, i done the test on the brushes like i saw on your video, i have the same model as yours, i get no power showing on the tester if i put my tester on l1, l2 or R1, R2 i get 3.5v wondered if you knew what the problem might be would really appreciate it, pete

[@TrueNorthist]

Thanks for the tips Styles. However, I am still not getting proper voltage at the 110 plug. (Nor the 220 but I will only refer to the 110 circuit) I get 3.88v~ across the brushes, 3.95v~ at both L1-L2 and R1-R2, and 0v~ at L1-R1. All good right? I show exactly 4v~ on my multimeter and it drops to zero if I switch the 110/220 selector to off or trip the breakers, so there is some sort of activity going on in there. The "pilot" light is off. The genny was run for 12+ hours without issues a few days ago but had no output the next day after an oil change. BTW, its an older Yasutora MDG3600CL Diesel with less than 100 hours on it. The engine is strong and the connectors inside the generator section are clean. Maybe my issues lay inside the panel? The genny in the following clip is exactly the same as mine, with some minor differences: kzbin.info/www/bejne/rZXMeHiBntGWa7M

[@Generatorguru]

+TrueNorthist Sorry for the delay it sent your message to the spam folder. What voltage are you getting with the AVR fitted? If that seems good voltage then the next place I would investigate is the Voltage Changeover Switch. Your readings from the test indicate that the alternator is good. www.generatorguru.com/mdg3600cl/

[@waqariqbal9946]

thankyou very much for your effort and sharing nice video. but i was little bit puzzled during video how can multimeter gives 5,10 volts without any supply. please elucidate this point.

[@Generatorguru]

+wajahat hussain This is a good KZbin video which explains how an Alternator works: kzbin.info/www/bejne/qpqueWduerKagac. There will be a residual voltage which is what we test.

[@gertrudemartins1317]

I was running my heater off my generator (3000 watts)for about an hour when the heater when off. I checked the generator and it was running and smoking so I shut it off. Would that indicate my windings or alternator is burnt? Great video, very educational.

[@Generatorguru]

Yes, you will need to get the alternator rewound by a Motor Rewind shop. It is arcing and burning the varnish on the windings.

[@habekrats]

Thanks to you and this tutorial my generator works again. Greetings from Holland.

[@diceman220]

Good job. When you take the reading, is the AVR pluged in or out ? Thanks

[@robertcontreras4636]

hello this video helped me out in a big way thank you... i have a tested brushes and the winding here are my results L1&L2 16.3. R1&R2.099 R1&L1.191 across the brushes 75.4.... if i heard right you said if the brushes read higher then the windings it would be the rotor?

[@engineeringdept.generatorg1760]

Sorry for the delay in responding. We have had a few technical issues on our KZbin and were unable to respond. Yes you are correct the rotor is failing. As your Alternator has failed the tests, you need either replace the rotor, or to contact a local “Motor Rewind Company” to see if they can fix it. These companies can vary in price, so if you have time, it is worth getting a few quotes.

[@slockfox]

Thanks for the video. I have a troy bilt 8250. I had 1.6 v between brushes. Is this too much?

[@engineeringdept.generatorg1760]

Can you tell me the other readings you are getting this will help me give you better advice?

[@slockfox]

Styles Generator Guru Thanks for the reply! Mine looked a little different. I had black and red wire going to brushes from avr. Then there were 4 wires going to avr. Red and blue hooking to one side of avr and red and blue hooking to the other end of avr. I wasnt sure if these were the correct wires to check but i checked them anyway. With avr removed completely, i had 1.6 across brushes. .7 from red to blue and .7 on the other red to blue and a .3 from red to red. I didnt think to check blue to blue. Im not even sure if these were the correct wires.

[@engineeringdept.generatorg1760]

Dear Sir/Madam Those were the right wires, it looks like the excitation voltage has dropped away from your alternator so it needs to be re-magnetised, please follow the steps below 1. To re-excite your alternator, we suggest you only use this method, as described by Generac Generators on KZbin: kzbin.info/www/bejne/Y321Z2WpopyIibc 2. Run the generator for 20 minutes without load to stabilize the magnetic field in the Alternator. 3. Test with suitable appliance to make sure the load is stable. If not go to step 4. 4. Repeat our tests: www.generatorguru.com/help-me-fix-my-generator-repair-advice/ If results are below 1 Vac, repeat step 1. If this continues please contact us. If results are between 1-7 Vac, but you are not getting full voltage at the sockets, then you will need to replace your AVR/Capacitor. If results are above 8-10 Vac range, then you will need to replace your AVR/Capacitor. But be warned that the high reading will damage the AVR/Capacitor over time. This could result in it lasting a fraction of the time expected on a stable alternator. If results are above 10 Vac range, be sure you removed the AVR/Capacitor before testing. If you have and are receiving this result, we suggest you take your generator to a “Motor Rewind” company for repair. You can find your local Motor Rewinding company by doing a search on the internet for “Motor Rewind.” It is worth asking for a quote from a few Motor Rewind companies as their prices can vary greatly.

[@slockfox]

Thanks a bunch for letting me know what the problem was. I couldnt get the drill to excite it but the 12 volt car battery trick worked great! Thanks again!

[@000001willy]

Excellent video. I would have appreciated better close-up shots but I think it was good enough to give me the general idea.

[@Generatorguru]

Hey thanks for the info We will try to rectify this in future. :) (PS. sorry about the delay in answering, for some reason KZbin sent this question to the "junk" folder. We apologise for the inconvenience.)

[@jimmyprophet8529]

Excellent video. I learned so much and learned how to diagnose my generator properly... Thanks generatorguru!!

[@paperwork1125]

I agree that this is the best instructional video. Might want to do it for companies and get paid for it.

[@vladimirparra1626]

So nice video..thanks teacher..i continue following you from República Dominicana..

[@hmarillejla7]

Hi I just stumbled on your tut and this is what my gen is doing. No v. The user's manual says that its the AVR. Is that so? Can I test it using a multimeter before buying a new one? I know the general principle how gen work but never seen an open one. Tks.

[@engineeringdept.generatorg1760]

Yes you can if you think the failure is in the alternator. Just watch this video to show you how to test the alternator. You need a very expensive piece of kit called a Megla-Meter to test the AVR, but if you run these tests you can discount any other faults. If it all tests ok, it can only be the AVR failing in the alternator.: kzbin.info/www/bejne/qnTCfaWoj8iraZo

[@bornID]

Thanks for the video, I tested my generator a Honda EM 4500x as per video I had a couple of differences, first only one set of windings two wires I had a reading of 4.2 volts, and secondly a reading of 0 over the brushes. Can you identify what the issue may be please by the way it's 240v producing no power JB

[@engineeringdept.generatorg1760]

Hi JB Normally if you are getting absolutely 0V it will either be a lack of connection between the brushes and the slip rings or one of the slip rings has become disconnected

[@bornID]

@@engineeringdept.generatorg1760 Thanks gene guru, must be the slip rings there is 0 reading there also, does this mean a new rotor, cheers, JB

[@engineeringdept.generatorg1760]

Hi JB Each slip ring should have one thin wire attaching them to the rotor coils, these break free quite regularly, it might simply be a bit of soldering required so check that next and if not, then the break is internal and it will mean either a new rotor or the rotor rebuilt at a motor rewind company

[@bornID]

@@engineeringdept.generatorg1760 thank you kindly, I'll get onto that , JB

[@Raycr]

I ]'m wondering what the electrical problem is when my Predator 6500 watt genset produces about 20 volts on the rotor when checked running as in the video? Will there be shorted windings then?

[@engineeringdept.generatorg1760]

Can you please contact us with a full set of results here www.generatorguru.com/need-help/ Regards The Generator Guru Team

[@marcberube176]

Great video!! helped me a lot. I have a smaller 3500kw 120v gen. I only get 1v on my brushes and on the R1 L1 test (that's all it has) I also get 1v. Is this normal for a 120v gen??

[@marcberube176]

+Marc Berube dohhhh.... wrong setting on my volt meter. Now I know I just need a AVR

[@Generatorguru]

+Marc Berube Contact you local office via our website. www.generatorguru.com/ and tell the engineer that you need to be sent the "Low Voltage" repair instructions. :)

[@gilahunter]

I have a Briggs & Strat. I did what you stated and have 3 volts on brushes and 3 volts on both L1 L2 and R1 R2, the unit is pushing 170 volts out of the 120, how can I adjust that, any suggestions?

[@skhurramshah]

Hi! I really liked the video its full of information, but I need some more information from you if possible, that my generator speed is too fast and it creates a lot of noise when I put on the load on it, someone told me to fix the speed through the screw near the carbonator. So would you please tell me anything which really help me out.

[@joelduval3309]

I get 2.5 volts at brushes and windings. Do I change brushes or the avr?

[@Generatorguru]

Hi there For fault finding or technical advice, feel free to contact us using the link below www.generatorguru.com/need-help/ This will allow our engineers to review your query and give you the best possible advice!

[@christopherjones6258]

thanks for the info! I have a Kingcraft 2000w 120v bought over a year, used once perfectly, tried today and No output. I get 19vac on brushes and 9vac and out of warranty. I would like to see if there is a way to check AVR even though I understand now my gen head is gone. :-( thanks again

[@engineeringdept.generatorg1760]

Dear Sir/Madam, As your Alternator has failed the tests, you need to contact a local “Motor Rewind Company” to see if they can fix it. These companies can vary in price, so if you have time, it is worth getting a few quotes. This is a much cheaper option than replacing the Alternator as the manufacturer charges over ½ the price of a new Generator and we would still need to get it shipped to you from China. Being so heavy, that would be very expensive and outweighs the economy of a new Alternator.

[@christopherjones6258]

I understand and thank you for the reply but Is there a way to test avr with a meter rather than just replacing it? I am also working on a Titan that someone said the avr and b4 buy parts, would like to test. Thank you, Chris(not a Madam--lol)

[@engineeringdept.generatorg1760]

Dear Chris There isn't a way to test the AVR with a meter, it requires a load bank which is very expensive and not very common, that is why we test the alternator for any faults to point to the AVR by process of elimination. If the rotor on the Kingcraft is outputting 19V then the AVR will definitely have failed. Perform the alternator tests on the Titan and let us know the results and we can advise you further. The test procedure can be found in the videos on this page www.generatorguru.com/help-me-fix-my-generator-repair-advice/

[@christopherjones6258]

Thanks Styles. I used oven elements to build a resistive load bank testing my home standby but wouldn't know how or which wires to use to test avr. I will just take your word on process of elimination. Thanks, again!

[@allansnow3690]

I have a predator 4000. I'm getting 1.0 v at the brushes, approximately 4.0v at the other three tests. L1 l2, r1 r2, l1 r1. Can you explain the out of range brush 1.0 volts and l1 r1 is above 0v sitting at 4.0v please?

[@Diy-For-Life]

Sure am stumped. The video really taught me a lot I didn't know thank you! but looks like I have 1.3v at the brushes (brand new brushes just replaced.) also Which lead is positive on brushes? I heard closest to you and closest to bearing. and 1.7 at l1 and l2 and same for r1and r2 and 3.1 r1 and l1. This goes the same voltage all the way to the plugs. I check everything behind the panel breakers and al checked out good. Confused avr takes 12v ac and turns to D.C. Right? Or no? I believe I'm getting about 6v D.C. Coming out avr. I checked stator it is not grounding out and .01 ohm resistance between each legs with panel wires removed for ground. Only thing I can think of is I have not checked the 12v or 3rd coil. It acts like it's not got a magnetic field. Any help would be appreciated.

[@engineeringdept.generatorg1760]

Dear Sir/Madam, As your Alternator has failed the tests, you need to contact a local “Motor Rewind Company” to see if they can fix it. These companies can vary in price, so if you have time, it is worth getting a few quotes. This is a much cheaper option than replacing the Alternator as the manufacturer charges over ½ the price of a new Generator and we would still need to get it shipped to you from China. Being so heavy, that would be very expensive and outweighs the economy of a new Alternator.

[@Moeterboater]

Hi Generator Guru. I have the exact same generator as you have in your very informative video. My problem is that when the motor is running and I go to turn the circuit breaker switch for the 240V to on, an awful grinding noise happenes and the switch trips immediately. Any ideas? Please help.

[@Generatorguru]

What were the readings as set out in the video?

[@mattbray3542]

I did the described tests on a power pro 3500 several times, and the readings across the brushes were around 48v each time. does that mean the rotor has gone bad?

[@Generatorguru]

As your Alternator has failed the tests (brushes too high), you need to contact a local “Motor Rewind Company” to see if they can fix it. These companies can vary in price, so if you have time, it is worth getting a few quotes. This usually is a much cheaper option than replacing the Rotor.

[@mattbray3542]

ok, thank you.

[@usenchristopher9942]

thanks to generator guru. your video is very much educational, please i need your assistance. i bought a working core and armeture and core for 2.5-3.0 kva generator but i am having deficulty on the connection of the core and panel

[@Generatorguru]

Hi! Please contact us on www.generatorguru.com/contact-us/ and we will assign you an Engineer to help. :)

[@Generatorguru]

+Rick Saffery You cannot test the AVR without a very expensive piece of kit called a Megga meter. This is why you need to do these tests to make sure there is no other problems in the Alternator. This will discount any other problems leaving the only possibility being the AVR.

[@johndavidson8955]

Generator Guru my UST 2300 reads 145-190 vac and HZ reads 75-79 time to scrap it?

[@Generatorguru]

John, These are the results without the AVR attached during testing? If not please test without it attached, if so, then follow the next step. If the hertz are that high then we would be questioning the speed of the engine. First, check the Governor Rod and all springs are in good order (especially the one over the rod to the top of the carb as a little play in the spring will greatly affect this.) Also, service the engine to be sure that nothing has gunked up the governor which sits inside the engine as this adjusts the speed. In North America, you want 60hz (50hz for European or Auz regions) so you need to slow down the engine if neither of the above is the case. On your generator, you can do this with the screw at the top of the carb. Turn slowly anticlockwise until you get the desired Hz. If this does not work you will need to replace the governor inside the engine. If you need parts we hold them for your generator. You can buy online on www.generatorguru.com/

[@glennavery3994]

Very educational video. Just need to move your camera a little bit closer to your work so we can see better as to exactly what you’re doing again very educational video. Thank you.

[@Generatorguru]

Thanks for the tip!

[@kingdon9690]

If the nuts on L1 L2 R1 and R2 are rusty will that cause issues? I have a Generac GP3300, and it's got very low voltage output. I hook up a drill, and it's super slow, if I hook up a light it's super dim. It was working fine last year, and it's a 2013 model. So it is an older generator, it was given to me by my mother in law who takes great care of her stuff. She never left it outside in the weather, and when it was used they had a box they built to keep the rain and snow off it. They also only used it maybe like 10 times before they decided to upgrade to a bigger one.

[@Generatorguru]

Rust happens so not a big deal usually. Chances are it will be your AVR (Or capacitor on some units without brushes.) Run the test in this video and it will help you pinpoint the problem. If you need any further help, pls contact our engineers via our website and they will be happy to guide you through the results. www.generatorguru.com :)

[@Currancchs]

I have a Champion 3.5kW portable generator and it works well for about an hour, then continues to run fine, but stops producing power. Testing at the GFCI outlet shows about 4.3v when it is not working. Testing across the brushes with the AVR disconnected shows 25 volts. Testing L1-L2 and R1-R2 shows about 3.7 volts on each while testing L1-R1 shows 0 volts. Given these readings, I assume that the bridge rectifier/my rotor (if the rectifier is not replaceable) are failing. A commenter on here mentioned that his unit's RPM was too high resulting in this condition and my unit does seem to rev a bit high. I further assume that no-load revs should be about 3,800 RPM, like most power equipment. Any chance its my RPM and my rotor is OK? Just not too sure how RPM and brush AC voltage with the AVR disconnected interact. Thanks for a very informative video in any case!

[@Generatorguru]

Hi! Thanks for getting in touch! We are having issues getting KZbin messages and really want you to talk this through with our Engineer that specialises in your generator. We can get an engineer to have a look at the results for you. We don not charge for advice, but, you will need to contact us on our website so we can get the right engineer with experience of your generator to assist you. :) www.generatorguru.com/need-help/ > Engineering & follow the questions. We are always happy to help! P.S pls state your location for the correct RPM requirements. It will depend on the hz used locally. :)

[@bradchapman2879]

I have a 4000watt predator generator. Ran great for 2 years but at the end of Hunting season I had an electric heater plugged in I my camper and when it kicked back on it ran wide open all of a sudden and I'm not sure if it was making any electricity or not. I need to get it going so I can run my devices at camp. Could you help me with a starting point? Thank you for your time and educational teachings which by the way are great. Thank you!

[@Generatorguru]

Please contact us for help on our website to open a ticket with a senior engineer. www.generatorguru.com/need-help/ We will require the result from running the tests in this video to help you. Please provide this with your enquiry. kzbin.info/www/bejne/qnTCfaWoj8iraZo&lc=Ugwo15WlXUwe1A7d1kh4AaABAg :)

[@rudeboz5486]

hi i wrote to you before about my generator losing power i have found out it my be the avr but not sure what new one i should order as the generator has 240 single phase and 1 380 3 phase so do i need to get a 3 phase avr or will a normal avr be ok to use and can i put bigger kw avr on ! one on it is rated 2.8 kw hope you can answer my querie

[@Generatorguru]

Hi! What you need is to take the Make and Model, and then to on look it up on here: generatorguru.com/. Then find the AVR on the page to order it (this Video will show you: kzbin.info/www/bejne/oouvoJp-o7GXn5Y). If you are not sure of the Make and model of the generator or want help in any way, we are very happy to assist you! Please contact our Engineers on generatorguru.com/need-help/ and we can get you an Engineer to guide you through it and be sure we get you the correct part. Kind regards The Generator Guru Team

[@driftervin]

Great video..I got 15 across the brushes but they perfect..not burnt in anyway..do yo u think they are the problem?

[@Generatorguru]

Hi there For fault finding or technical advice, feel free to contact us using the link below www.generatorguru.com/need-help/ This will allow our engineers to review your query and give you the best possible advice!

[@horsesnsports]

hi guru, i have a generator that is ok on 230v but not on110v. the indicator needle says 110v but if you put a multi meter in the yellow socket outlet it reads only 49v-50v. it used to work fine.

[@Generatorguru]

Tania, It will either be the plug or the breaker failing. (It will not be the alternator or AVR as you are getting the full 230v.) If the plug is failing you will see burn marks on the back. If no burns on the plug then I would replace the breaker. :) If you need parts please see our website: www.generatorguru.com

[@csiautodetail]

Is replacing the AVR or brushes expensive?. I have a 3250 wats generator that I use to run a Wet/ Dry Vac, the generator starts fine but when I plug the vac I don't get any power.

[@willmorrison6376]

hello i have an dunlite gen . its an oldie the board in it is a pr102b. not making any power unless you put a drill and spin it. just wonder how to diagnosis the board

[@Generatorguru]

Sorry it is not a generator we have worked on. Maybe these guys can help: www.powersystems.com.au/products.php?CategoryID=1&BrandID=7

[@malcytull]

Great video, thank you. I have a Nixon KGE 5500X, could you please tell me the tappet clearance or better still give me a link to a manual. Many thanks, Malc.

[@Generatorguru]

+Malc Tulloch Intake =0.015 Exhaust = 0.020

[@malcytull]

+Generator Guru Thank you very much :-)

[@macDaddy2364]

When testing the brushes on my gernerator like you described I was getting 34 volts? What's does that mean?

[@Generatorguru]

If you removed the AVR like your are ment to for the test, it means the diodes in the rotor have blown. Best to take it to a motor rewind shop and see if they can fix it for you. (Worth shopping around as prices can vary a lot!) :)

[@adriaanwinkelmans139]

Hi, Very clear explanation! I had 210 instead of 230 Vac on my generator output. All values of stator and rotor were fine. So, I raised the output voltage up to 230Vac by adjusting the potentionmeter screw on the AVR. So far so good, but now the 12Vdc 8.3A output is giving me too much voltage: 21Vdc. I assume this is a consequence of adjusting the AVR. Is there a way of to get the voltage back to 12Vdc without lowering also the AC output voltage? (Off course I could solder some resistor in series with the rectifier but that seems like an uneconomic solution...) For your information: I tested the diodes on the rectifier bridge that goes to the 12Vdc output and all 4 diodes seam fine. Generator: GENERMORE, CF6500 Thanks in advance!

[@Generatorguru]

You AVR is failing and needs to be replaced. There is no fix without replacing it for a new one. We do hold AVRs for Genermore Generators and would be happy to help you. You will need to contact our engineer to identify your particular AVR as they made this generator with 3 different alternators over the years. Please contact us on www.generatorguru.com/need-help/

[@ryanp3274]

Hello, I have a coleman Powermate 6250, Shows around 128 volts coming out of the 110 plug. But the amps must be low as has a hard time starting my furnace. Brushes look good. AVR?

[@Generatorguru]

If the voltage starts to creep up, and the engine speed is correct, it is usually an indication that the AVR is starting to go. Run the tests to be sure nothing else is failing though and causing damage to the AVR. As the capacitor in the AVR fails it can either get the inner plate closer (raising the voltage) or further apart (dropping the voltage, though service engine 1st to be sure this is not running slow.)

[@ryanp3274]

Thanks for the reply! I did the tests that you showed in the video. Disconnected brushes and AVR. Across brushes, 22.4V. L1&L2 1.9. R1&R2 1.9. R1&L1 2.0. Tried throttling engine, maybe gained .5 volt. Engine has a governor. Thanks!!

[@Generatorguru]

Your Rotor has failed the tests. This indicates that the diodes in the rotor have blown and are not directing the current. Some rotors have diodes that can be replaced. If yours does you will see them between the magnets on the rotor end. If they/it is not visible you will need to replace the rotor or see if someone can rebuild it for you (motor rewind shop.)

[@ryanp3274]

Model # of my generator is PMA525302.02. In parts shows rotor is unavailable. So apparently may be junk.

[@Generatorguru]

Try saving a search on ebay for this model with words like "spares" or "repairs" (i.e. Coleman PMA525302.02 repair" "powermate PMA525302.02 spares repairs") and you might find one cheap where the engine has blown. Alternatively, list yours for sale. If you state what is wrong a local repair centre or owner might be able to use it.

[@Generatorguru]

Hi Amber, Are you getting any reading across R1 and L1?

[@jiveturkeylegs8692]

Hi.. I'm getting about 5 volts at the brushes. Do I need to replace the AVR?

[@Generatorguru]

The brushes and rotor look good. Did you get a windings reading? If also 5vac, then yes you need a new avr! See our website for AVRS: www.generatorguru.com

[@gmaster5482]

Thanks for your video. But can you tell me how much the input and output voltages across the AVR. Because i have replaced 2 AVRs but generator has still no power output. What should i do?

[@engineeringdept.generatorg1760]

Thank you for contacting Generator Guru can I please ask What results you are getting from the tests on the video Regards The Generator Guru Team

[@gioiavin]

What does it mean when you test the AC voltage at the brushes after you remove the AVR as shown in the video, but instead of more than 5 volts it has almost no AC voltage across the two but I know the brushes to the connector have good continuity. Would that mean that the rotor is bad?

[@Generatorguru]

If it is 3v-5v all is good. If under 3v we suggest you flash the alternator. For instructions on this proceedure, please see our Help centre>Repair Help : www.generatorguru.com/need-help/.

[@jimcorman3172]

I just watched your video on diagnosing output problems with the Predator generator. Great diagnostic video! I have the 6500 watt generator which stopped producing electricity. After removing the AVR and starting the generator, I found I have no voltage at the brushes or at L1, L2, R1 or R2. Brushes were removed and inspected. Brushes appear normal, and are not sticking in the unit. Any ideas or any other tests that can be run on the unit. Unit is approximately 2 years old.

[@Generatorguru]

HI. Sorry we have only just had this comment come through but I see it is 3 months old (not sure what happened there!) As your results are showing a low voltage so we suggest you “Flash” your alternator. Follow the steps below: To re-excite your alternator, we suggest you only use this method, as described by Generac Generators on KZbin: kzbin.info/www/bejne/Y321Z2WpopyIibeGun the generator for 20 minutes without load to stabilize the magnetic field in the Alternator.Test with suitable appliance to make sure the load is stable. If not go to step 4.Repeat our tests: kzbin.info/www/bejne/qnTCfaWoj8iraZp9f results are below 1 Vac, repeat step 1. If this continues please contact us. If results are between 1-7 Vac, but you are not getting full voltage at the sockets, then you will need to replace your AVR/Capacitor. Find your replacement parts here: www.generatorguru.com/categories/Make-%26-Model/ If results are above 8-10 Vac range, then you will need to replace your AVR/Capacitor. But be warned that the high reading will damage the AVR/Capacitor over time. This could result in it lasting a fraction of the time expected on a stable alternator. If results are above 10 Vac range, be sure you removed the AVR/Capacitor before testing. If you have and are receiving this result, we suggest you take your generator to a “Motor Rewind” company for repair. You can find your local Motor Rewinding company by doing a search on the internet for “Motor Rewind.” It is worth asking for a quote from a few Motor Rewind companies as their prices can vary greatly.

[@Generatorguru]

Hi there Check for broken connections between the rotor coils and slip rings

[@hensonorr9343]

if the air filter casing is cracked or broken will that cause the breakers to trip on the generator ?

[@Generatorguru]

Hi there, Not directly, no, it might alter the running of the engine slightly but shouldn't affect the output much at all, certainly not enough to trip the breakers

[@collynpunupo8080]

Thankyou, I have gained a valuable infor to repair my 4kva gennset . In this case, the problem is no power output so let me try it out my self.

[@Generatorguru]

Glad it helped. If you need any help, contact us through our website and we would be happy to assist. generatorguru.com

[@philliplee3833]

I have a Wacker GP6600A. The unit had sat for 2-3 months and worked fine prior. When I started the unit again it ran like there was a huge load on it and I noticed smoke coming from the fan end of the unit. I Stopped the unit after about 20 seconds. One of the brushes was broke and was replaced. When started again the same issue. When the brushes are unplugged it runs at full speed. Any suggestions?

[@Orthodoxuk]

The output on my generator seems to be taken from L2/R2 (250v) currently reading 6V AC. Should this be 0V like your L1/R1 description?

[@Generatorguru]

Please set up a ticket with our Engineers to discuss further as there could be a few reasons. (We do not charge for this service.) www.generatorguru.com/need-help/

[@MrSmokercraft16]

I am trying to replace a motor on a Troy Built 7000 (the motors bad). Do U have any videos I could watch that wood help me out. Thanks

[@Bsetzd]

I have a question I got a champion 4 k generator it just started doing this out of the blue when you put a 1100 watt load on the initial startup my window ac unit on the generator makes a buzz like sound coming out of the generator head what is causing this? now if I run my coffee maker that's pulling 1500 watts continuous it's absolutely fine?

[@Generatorguru]

+Brandon Setzenfand We think it is best you call us to discuss it with an Engineer. Contact your local office via our website. www.generatorguru.com/ :)

[@DecosGarage]

do you have any videos on testing digital avr?

[@Generatorguru]

Please contact our engineers via our website generatorguru.com for help with this issue

[@AN-kg4ei]

great video - very comprehensive and I learned a lot.,, I'm about to tackle a 'no power output' issue with a 4k Champion. I'm wondering if testing the alternator with a scope or looking for diode ripple is a good quick indication of a dead alt? I assume that as long as the specs are similar, any AVR that can be securely mounted in the housing can be used (snip the pigtail/molex and solder)? Thanks again!

[@Generatorguru]

+A Nixon No!!!! Don't do it!!! You cannot just use any AVR. The components are rated for the lengths and thicknesses of the copper in the Alternator. Wiring can also change from AVR to AVR. We often hear from customers who have bought a cheap AVR or used one from another Generator and burnt out their windings. (Very expensive job)