Northern Lights Generator- No power output - sometimes

[Water Music 440]

I have a Northern Lights M673L3 which has an unpredictable intermittent fault that it produces no power although the motor runs normally. I have checked all the tips from other threads on the same subject with no success. The frustration is that sometimes it works and sometimes it doesn't.
I am guessing the field coil is energised when the button is held down to make the glow plugs work, I usually depress this button for 15-18 seconds before pushing the button to turn the stater motor. I have checked the breakers and fuse, all ok.
Can anyone advise what to check or do differently, I have emailed the manufacturer but no response received.

[LakeSuperior]

We had chased the same symptom for about a 1.5 years on our 1999 NL generator and it made me want to tear my hair out. In our case it was the field controller board. The generator worked perfectly after the board was replaced for $600. I am sure that the starting battery juice is heating your glow pugs on a different circuit not related to AC output.

[jstevens]

If the M673 has brushes, you should check them. That is probably the least expensive part to replace. I have a M642 and I had a similar set of problems while in the Bahamas in 2008. I first replaced the AVR board with no improvement. Then I replaced the brushes and the problem was solved. Should have done it the other way around, but that was the advice I was getting from the NL dealer in Nassau.
In my case sometimes the generator would only output 6VAC. Finally it became a consistent problem.

John

[svmariane]

Originally Posted by jstevens

If the M673 has brushes, you should check them. That is probably the least expensive part to replace. I have a M642 and I had a similar set of problems while in the Bahamas in 2008. I first replaced the AVR board with no improvement. Then I replaced the brushes and the problem was solved. Should have done it the other way around, but that was the advice I was getting from the NL dealer in Nassau.
In my case sometimes the generator would only output 6VAC. Finally it became a consistent problem.

John

What he said. Resolved my NL genset prob.

[LakeSuperior]

We fiddled with the brushes most of the 1.5 years of frustration. Sometimes it seemed to fix the problem and other times it did not...because the problem was intermittent.

Be careful with the brushes as they are fragile and easily damaged.

We were never able to get the resistance across the slip rings and the brushes to consistently meet the specifications.

Once the board was replaced the generator did not seem to care what the brush resistance was. It just worked fine.

[Water Music 440]

Thanks all.
After four attempts to get it running last night we had to run the boat engine to charge the batteries. The generator fired up fine this morning, go figure!
We replaced the AVR 18 months ago when a number of appliances (probably too many) were in use and it revved up and the voltage went off the scale $750 in Australia.
I have had the brushes out, there'e plenty of meat left.
Not sure what a "field controller board is"
NL have just replied to my query, I will post any information after they review the load info I sent them

[Water Music 440]

Results!!!
Northern Lights responded to my email, hurray!
Over the next couple of days we exchanged information describing the normal use, loads etc.
The conclusion:
If the climate is warm you should be holding the Preheat/Bypass switch for about 10 seconds before cranking and an additional 5 seconds or until the oil pressure has come up after starting.
Load the unit very heavily almost over load it if possible only for a very short time.
By doing this you will put very high voltage to the exciter field and hopefully raise the residual magnetism of the Rotor. This magnetism is what gets the voltage going upon start up of the unit, if it is low it may sometimes not get the AC Regulator started.
When shutting down remove all load, let the motor run for a few minutes and then turn off.
It has worked well so far, spare set of brushes are on order.
Many thanks to NL for their advice

[downunder]

Good result.

[bmintz]

I had a similar issue. I spent hours on the phone with the tech tracking it down. We never solved it. I bought a new avril. $700. When I went to install it I found a wire crimp connector that was coming apart. I remade the crimp. Haven't had another problem. The AVR is still new in the box.

[lhuff35204]

Ours failed intermitenly in the Bahamas. I removed the copper slug from the AVR board, cleaned it and all contacts, checked for loose crimps. I also support the idea of starting under a load.

[s/v Jedi]

I once zapped the residual magnetic field by reverse feeding power into the generator end. Only 3-6V output after that.

Googled/Youtube’d and got it going again by putting 12VDC somewhere to build up the field, then run it at high load to restore the field permanently.