Brushless generator not producing any power

Somewhat tangentially to my other construction videos, I needed to diagnose and repair my brushless generator this week. Here is how that was done.

Brushless alternators use a capacitor to introduce a charge into the windings. This gets them excited so the alternator will produce electricity. When my engine RPM surged, it surged the alternator and the capacitor blew to protect all the electronics downstream…
If the alternator is working, it produces a ~5 volt difference (plus or minus a volt or 2) across the capacitor. So, I just had to check the AC Voltage with my multimeter. It turned out the voltage was OK.

By process of elimination, I decided to order a new capacitor.
My original was covered with a layer of rust, so I couldn’t read the specifics. I checked the internet to find the right one for my generator, a 40µF, 370VAC generator capacitor. The genuine PorterCable part costs 60$. Now that I knew the specific properties, I was able to search based on that and found a Genteq knockoff that only cost 16$ with delivery. It claimed to be just as long lasting (60,000 hours), and like the much more expensive OEM product, it is also “self-extinguishing” so I won’t die in a terrifying fireball if it fails.

Its physical dimensions are a little different, but it fit. And more importantly, my generator works again.
Now my generator can do its job and give me electricity on my jobsite.

[lightning]

If one is tempted to think a short, to the point, simple vid won't help people. This video proves that wrong.
Amazing how many people had the same problem and you helped them solve it. Love this age of information.

[jhawksfarm]

Thanks for the video! I have the same generator and it stopped putting out power. I got the capacitor locally for $14.00 and took the new $900.00 generator back to Lowes!

[ManlyManStuff]

Awesome video!
I just bought one of these and it works great but I would rather have the knowledge and parts available instead of cursing at it during a hurricane. Ida sucked.

[hondahamis]

Thanks for the Tip i have two sets of 1.5kva unit the Avr and capacitor my capacitor type been broken for 2 years now i did not mind fixing it because my AVR type working well for 6 years sad to say last week it give up producing flactuating voltage the thing is quarantine lock down no shops is open right now selling AVR so i watch your VIDEO UNDERSTANDING MY CAPACITOR TYPE GENSET UPON CHECKING MY CAP ITS BLOATED BUT AGAIN NO SHOPS IS OPEN. GOOD THING IS MY NEIGHBOR IS AN ELECTRICIAN HE HAD SOME CAPACITORS BUT 10uf only instead of 12uf but right away upon installing it work immaculately. Thanks your a life saver

[rosewoodsteel]

My Generac XP8000E produced low and then no voltage output. I replaced the capacitor and she is powering up all of my selected circuits again. Instead of hauling it to a authorized Generac repair shop and forking out big $$, I spent a little time and few dollars on the capacitor. Thank you for the video!

[footonearthchris]

Thank you very much for this! I was able to fix my generator thanks to you.

[robertmattison]

Excellent video, well done and quick and to the point. Thank you for making it and posting to YouTube. Yes, Published on April 26, 2016. I watching it August 17, 2017 @ 6:51 EST

[ngrader]

For oil caps, the deformed silver buldge on the top of the cap is a good visual fail indicator. That bump is much smaller and uniform when working. I used to replace lots of light ballast caps, and they always deform when they go bad. At one point in time, I knew why. (also, I've never seen a cap that rusted. Life in the desert. LOL)

[pasioncazaycocina]

This video makes may day i had it the same issue and got fixed my self by replacing bad capasitor after seeing this video. Thanks.

[victorrobinette]

Great video. I'm having the same issue. My capacitor is bad too.

[JimFixIt]

Great video. My generator was doing the same thing. I ran the tests with the same results you’ve shown. I have a new capacitor coming tomorrow. Fingers crossed this was a $15 fix. Thanks!

[Mikesorrento]

Very good. These electrolytic capacitors will dry out over time, especially due to non-use. Run genset every month or two for 15-20 minutes UNDER LOAD. This will accomplish a few things. First, it will keep the electrolytic capacitor(s) in good shape and charged. Second, moisture in crankcase oil will be burned off and carburetor gumming will be kept to a minimum. Third, your engine seals will be kept lubricated and lastly, you will spot any performance problems and be able to fix them BEFORE you loose power and really need the genset. So many will not take these simple steps and when they go to use genset, it either doesn't start, or produce use aviation fuel if you can. It has a much longer shelf life and has no ethanol, which can damage some older carbs. If you can't get aviation fuel, use stable and run your carbs dry always....

[beddie]

THANK YOU FOR THE HELP I FIX MY GENERATOR IT WAS THE CAP.

[irmaulloa]

thank you very much, got my generator back on line for my foodtruck.

[tomnorton]

Thanks for posting this! My generator works again!!!

[wazzaracer]

always be super careful when handling large, can type capacitors. In this case, the machine was only sending it 5 in many appliances and devices, hey can enough voltage and current to deliver a nasty or deadly shock.

[fsrodeo]

Nice video, short but essential, great!!

[robertmattison]

Okay, you got the generator working, I like your video, because you added humor into it. You have gift in front the camera.
And your voice is excellent. Perhaps a career doing voice over for Anime movies.

[thomasschwarting]

OK, so I'm watching your video and you're testing the voltage going to the capacitor which is running between 4 & 5 volts. I have an older Honda generator, a pro series 5500 and also has no power output. When I check the voltage going to the capacitor, it's got 9.8 volts. Is there any way to compensate for that high voltage? I'm also assuming that the capacitor is probably no good due to the high voltage going to it. Now if it's got voltage going to the capacitor, does that mean there's a possibility that this generator can still be salvaged?

[MrPancho]

I have a generator a brushless generator that has a capacitor on it as well I got a hold of a tester and I ran it the same exact way you ran yours. After selecting the V~ button it reads 1.020 it will vary running up or down . The generator is a Powerback 5250