Page 1 of 2

Northern Lights Genset Brushes

Posted: Sun Jul 11, 2021 7:27 pm
by Pisgah
I stopped getting voltage to my panel from my NL generator the other day. The service dept at NL was very helpful with diagnostic steps. The first was a resistance check on the brushes. Instead of perfection which would be a little over 16 ohms, I got 127. I’m trying to figure out how to access the brushes to examine them. Can anyone help?
Randy Catlin
Nighthawk
PDQ34

Re: Northern Lights Genset Brushes

Posted: Sun Jul 11, 2021 8:27 pm
by deising
When you say you stopped getting voltage, that implies zero output. I had that happen once and found a fuse in the control box was blown. Replacing that restored operation and it has worked fine for several years.

Are you sure the brushes are your problem?

Re: Northern Lights Genset Brushes

Posted: Mon Jul 12, 2021 7:24 am
by Pisgah
The three relays seem to be fine. My AVR has a fuse holder on the board, but there is no fuse, there is a copper wire slug of the same diameter, which apparently was supplied by NL. The rest of the board has no obvious signs of failure.
I think I have to check the brushes. I wouldn’t think they’re worn down since the generator has less than 400 hours since 2006. If they are indeed the problem, I think it more likely that they just need to be cleaned.
It was suggested that I try to access the brushes by opening up the bulkhead at the back of the locker under the fridge. That area was covered with insulation by a prior owner. I hope to avoid surgery.
Thanks,
Nighthawk
PDQ 34

Re: Northern Lights Genset Brushes

Posted: Sat Aug 07, 2021 12:31 pm
by makala
I just played with my generator for a couple of days (see post about checking the NL generator 12V ground). If the engine runs it's not any of the four 12V relays (I studied the wiring diagram for days when troubleshooting my generator).

Obviously you probably checked the 120v circuit breakers on the side of the control box. You might want to try to check if you are getting 120 volts on both sides when it's running if possible.

If you unscrew the four brackets holding the generator base "tray" to the hull you can slide the generator forward several inches. After sliding forward you will see about 4-5" of clearance at the generator (aft) end, which looked like it would be enough to remove the cover and get to the brushes with a shorty screwdriver, perhaps using a mirror for help.

I wouldn't advise cutting from behind the refrigerator. The area is sealed for a reason (sound and CO emissions, likely). On ours (2006) there is a plenum to provide fresh air to the generator head that you would also have to cut into. Not worth it.

You could feasibly slide it more forward if you disconnected the four isolators the generator, but I don't think it's necessary...

Let us know how it goes... I am thinking about replacing ours as a matter of maintenance since we are creeping up on 2500 hours and brushes are cheap (in marine bucks anyways)!

Oops, almost forgot- One thing I read regarding 120 power output is that if you aren't getting it you could try to "flash the field", see here:

https://www.cruisersforum.com/forums/f1 ... 50885.html

Thanks,
Doug
B-Side MV 34 #102

Re: Northern Lights Genset Brushes

Posted: Sat Sep 25, 2021 9:18 am
by Pisgah
Thanks for the input!
When I did a follow up check of the brushes, they were fine. At the suggestion of NL and helpful fellow PDQ owners, I flashed the field, a very simple procedure.
Problem solved!

Re: Northern Lights Genset Brushes

Posted: Wed Sep 29, 2021 7:17 am
by makala
Pisgah wrote: Sat Sep 25, 2021 9:18 am Thanks for the input!
When I did a follow up check of the brushes, they were fine. At the suggestion of NL and helpful fellow PDQ owners, I flashed the field, a very simple procedure.
Problem solved!
Hi Randy,

Can you post the procedure you followed to flash the field for our NL generators? It would be nice to have it documented in the forum for others with the same problem.

Thanks!
Doug

Re: Northern Lights Genset Brushes

Posted: Mon May 22, 2023 2:15 pm
by Pvbeach1
Hello All,

In searching the Forum this is all I could find relating to my current issue. We are down in the Exumas and our Northern Lights generator has stopped supplying power to the panel. I have a call into tech support at Northern Lights but haven’t heard back yet. So here is my question…. Has anyone performed this process of “flash the field”? I have not been able to find any clear step by step instructions.

Thanks in advance…

Re: Northern Lights Genset Brushes

Posted: Tue May 23, 2023 12:51 pm
by duetto
hi,

you may want to search and pose your question on this forum: https://www.trawlerforum.com/forums/s6/

if the link doesn't work it's trawler forum then power systems sub group.

they have a lot of discussions on northern lights and have quite a few professional contributors.

Re: Northern Lights Genset Brushes

Posted: Wed May 24, 2023 9:22 am
by Pvbeach1
John,

Thank you for your input. After discussion with Northern Lights Tech Support and the NL dealer in Nassau and diagnostics performed at their direction it was determined that "flash the field" would not correct my problem. It looks like we will just live with it not working until we get home to St Augustine and then have our NL dealer assess at that time.

Re: Northern Lights Genset Brushes

Posted: Wed May 24, 2023 9:28 am
by duetto
sorry to hear that....do you have solar?

Re: Northern Lights Genset Brushes

Posted: Thu May 25, 2023 7:53 am
by Pvbeach1
Unfortunately no we don’t have solar. The big question now is, will running the engines charge the house batteries?

Re: Northern Lights Genset Brushes

Posted: Thu May 25, 2023 1:28 pm
by duetto
really depends on your electric demands. we've done it in the past when we had genset problems but only for a day or 2 until we went back to dock and fixed genset. i don't think std alternators will measure up to the battery charger.

did nl give you any thoughts on what the problem might be?

Re: Northern Lights Genset Brushes

Posted: Thu May 25, 2023 8:26 pm
by Pvbeach1
NL only said that it was not as simple as replacing the brushes. I will update once we get home and have a final assessment. Thanks again...

Re: Northern Lights Genset Brushes

Posted: Thu May 25, 2023 8:52 pm
by duetto
one last question: do you know if nl has a capacitor? i will say up front, i do not have an nl, but have 2 other generators of different brands on 2 different boats. in both boats, on multiple occasions, when the genset stopped putting out ac it was b/c of a blown capacitor. if nl has one, it's a cheap test to go to local hdw store and get one. they are std on ac units so local hdw will probably have one that would work as a test. probably not the problem but might be worth a shot.

Re: Northern Lights Genset Brushes

Posted: Sat May 27, 2023 7:06 am
by Pvbeach1
I don't know but I will call NL tech support to get some advice in that regard. Thanks for the tip.