Northern Light 6.5Kw generator not generating power

[Swiss sailor]

Hi all
On my 1999 H410 sailboat, I have a Northern Light 6.5Kw diesel generator (model M673) installed. I use it to charge the batteries or to power the ACs at anchor.

Since we did mainly work on the boat over the last two years, we hardly ever had the chance to use it. So the generator did only run for a couple of minutes, when rinsing the cooling circuit with fresh water.

The unit is installed deep in the aft locker. With the noise insulation around it, it is almost inaccessible, which is another issue, I'll address. The noise insulation panel are designed in a way, that the water intake line, power lines and the exhaust are running through the front element, which does not allow to remove the front panel (see picture). I do have another very limited access from the top, through the locker in the cockpit.

Now when firing the unit up, it generates approximately 7VAC instead of the expected 115VAC only. The volts are read at the main panel.

I tried to put some and heavy load on it (the two ACs, the 60amp battery charger etc.) without success. Then I played with the power switch, changing from shore to onboard power etc. No success. I also had a marine electrician aboard, and we made our way to the generators electrical control box. We also could only measure 7volts directly at the generator's control box. So I discarded the idea, that the cables from the unit to the panel could be the cause of the issue.

As the next step, I'll change the setup of the noise insulation. But this will only help to improve the accessibility of the unit, not to resolve the problem.

I asked the boat yard and they immediately recommend me to pull the whole unit and have it inspected and serviced. As a budgetary estimate, they talked about $3'000.- to $4'000.-, creating a huge hole in the pocket....

One year ago, the engine was spiting out cooling fluid through the expansion bucket. It made a huge mess... It is possible, that some water sprayed over the generator unit. It turned out, that the heat exchanger end cap (a rubber bellow) was misplaced and caused water from the primary circuit to enter the secondary circuit. We did reposition the end cap, flushed the engine several times and filled up with new coolant.

Maybe it is a simple common issue, with these units, allowing for an easy fix. Right now, I'm far away from the boat. But I'll be there in October, trying to resolve the problem.

Any suggestions / experiences, which could help me identifying the cause of the problem?

All help is much appreciated.

Thank you!
Marco

[smac999]

I know on the really older units they basically lose magnetism In the generator part if they don't run. (like the field circuit of an alternator) and need to be manually magnetized / polarized or something... only seen it once, on a gen that sat a few yeas. and it was a really old gen. not sure if the new ones are similar. I belive that one was putting out a few volts as well. but I wasn't the one who fixed it.


you really should be running the gen at least once a month.

[sy_gilana]

Look up "Flashing the field" and get the shop manual. It will help, and the folks at NL are very helpful

[colemj]

If flashing it doesn't solve the problem, then it is most likely the AVR.

Mark

[jkangas]

Mine stopped producing power once and it was the brushes.


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[Caliber40]

Assume you checked the AC breakers on the gen set panel?

[svinvictus2]

Originally Posted by Caliber40

Assume you checked the AC breakers on the gen set panel?

Ah yes....check the breakers and the exciter fuse and all the connections to them. It's a simple job but often the simplest things are the issue.

When checking the fuses first check continuity with a decent and proved tester but also take a spare NEW fuse and replace the old one just to make sure.....
Vibration will often shake connections out so look closely at al end connections for a loose wire.
Good luck....

[Electricmanknow]

Electricmanknows
I have worked on all things electrical and hate to say anti freeze is deadly to humans and all relays wires and things that conduct electric .
with out direct access to the unit I would pull it --only way to be safe -cables need to be tested and visually inspected
Wishing you well and good seas John out

[timbenner]

I had a problem with my 5kw Phasar generator, made in Riviera Beach FL. The boat yard said it would cost $3000 to re-wind the generator, plus labor. I called Phasar and bought a brand new generator that bolted onto the 2 cylinder Kabota diesel for $750. Entire generator unit - brand new. Be sure to check that out before trying to repair it. Most of the generator money is in the diesel, not the generator and the diesel will out live a number of generators.

[ex-12m-guy]

Check the following, in order:

Small fuses on the AVR (automatic voltage regulator board, usually found
inside the main alternator junction box.)

Replace the AVR with a new one. If this turns out to not be the problem, a
spare AVR is an essential spare in any event. Non-working AVRs can sometimes be returned for rework.

Check all diodes in the "diode ring" for shorts or opens. The ring is located on the alternator shaft under the end bell housing. If bad, replace the ring as a unit.

If so equipped, check brushes on the slip rings. (Modern alternators may not have brushes and slip rings.)

Check all windings for opens and grounds. Bad windings means a rewind job. As suggested above, a new alternator end may be a better option vs. a rewind.

[LakeSuperior]

Do 2 pre-steps to the above list!!

Originally Posted by ex-12m-guy

Check the following, in order:

1. Flash the rotor to create magnetic field.

2. Check brushes.

3. Then start with the following:

Small fuses on the AVR (automatic voltage regulator board, usually found
inside the main alternator junction box.)

Replace the AVR with a new one. If this turns out to not be the problem, a
spare AVR is an essential spare in any event. Non-working AVRs can sometimes be returned for rework. ~$600.00 part

Check all diodes in the "diode ring" for shorts or opens. The ring is located on the alternator shaft under the end bell housing. If bad, replace the ring as a unit.

If so equipped, check brushes on the slip rings. (Modern alternators may not have brushes and slip rings.)

Check all windings for opens and grounds. Bad windings means a rewind job. As suggested above, a new alternator end may be a better option vs. a rewind.

[ex-12m-guy]

For a replacement AVR, check Amazon. Enter automatic voltage regulator in the search box.

They offer universal (generic) models from $25 up.

[Ericson38]

Is this your manual ?

http://www.northern-lights.com/media...pdfs/OM673.pdf

They don't go into low AC output (troubleshooting sequence) most likely have it in the service manual.

Good diagrams for DC and AC though.

[Swiss sailor]

Thank you all for your support and the good recommendations. After improving the accessibility, I'll try to track the issue down, using your advice.

I must admit, that some would call me electrically slightly challenged

From what I have read in your replies, some more questions came up:

1. I read somewhere else, that I could flash the field by the following procedure:

Pluging in a electric CORDED drill in to one of the outlets, starting the generator, switching to generator power, pressing the go-button on the drill (it won't turn now), turning the drill manually and quick, which will generate enough power in the drill to flash the generators field. It does sound almost too simple to work. Anyone tried this with success?

2. I must say, that we did not measure the breaker on the pannel for functionality. But we measured the power directly at the generators control box. No power reading. I would assume, that this eliminates the measuring of the breaker to resolve the problem. Am I right?

3. Does anyone have a shop / service manual in PDF format for this generator? I could not find one online and would highly appreciate, if someone could PM one to me.

4. The advice with the AVR as a spare part is certainly good. This appears to be a high value part. At least the original one from Northern Light. Some recommended to shop on Amazon for a generic AVR. What would be the key indicators to look after, or would anyone be suitable, as long as the voltage and Hz are selectable accordingly? Are there more facts to look after such as Amps, brushes vs. brushless etc.? Did anyone replace the original AVR with a generic one and could provide make and type?

I'm sure I'll have more questions as soon as I get to the boat. But thank you all once more for the great help!

Marco

[LakeSuperior]

Originally Posted by Swiss sailor

Thank you all for your support and the good recommendations. After improving the accessibility, I'll try to track the issue down, using your advice.

I must admit, that some would call me electrically slightly challenged

From what I have read in your replies, some more questions came up:

1. I read somewhere else, that I could flash the field by the following procedure:

Pluging in a electric CORDED drill in to one of the outlets, starting the generator, switching to generator power, pressing the go-button on the drill (it won't turn now), turning the drill manually and quick, which will generate enough power in the drill to flash the generators field. It does sound almost too simple to work. Anyone tried this with success?

Marco

There are specific directions to flash the rotor for the NL gen set. You will die of old age before the above would work.