Comments from other Northern Lights owners on what they would change on their units.

Northern Lights 8kw generator

I have a Northern Lights 8 KW which engine and generator are made in Japan. Alaska Diesel likes to brag a lot about their gear. Don't believe them. It is a good rig but needs work before it is satisfactory, such as: engine-side stop/start controls, output breaker, local outlets, engine-side oil pressure and temperature gauges, 120 deg shutdown "clixon" switch on rubber exhaust hose (available at HVAC store, it has saved me from replacing that hose a dozen times), shield (I use duct tape, but a stainless shroud would be nice) around seawater pump shaft area to prevent spraying seawater into alternator when pump seal fails, strainer on hose output of seawater pump (I used a little plastic one designed to protect the potable water pump) to catch rubber bits, indicating breakdown of impeller and to prevent fouling of heat exchanger, etc., and in my case at least, installation of pre-start lube oil pump. It would also be a good idea to junk the $165 toy alternator that comes with the machine and replace it with a run-of-the-mill $45 Delco. You would have to make a new bracket but you will get twice the output at a quarter of the cost and ready availability. Another thing, the cast iron exhaust elbow rotted out after a few years. I had to make a stainless one. Get a stainless one right away while it is easy to install. There is something that rattles inside the generator end when I shut the machine down sometimes. I don't have a clue and neither does my dealer. So far, the machine runs OK, but it does make me a little uncomfortable.
 

I have a Northern Lights genset. Some things I did to it when I installed it:

Local pushbuttons to prime, start, and stop the unit from engine-side.

Local oil pressure and temperature gauges on the engine.

An ammeter to check on the starting battery charging alternator.

A freq meter to adjust the governor.

An engine hour meter to know when to change the oil (a MUST!).

Circuit Breaker on the output line. There were already circuit breakers on the field and 12 VDC circuits.

120 and 240 vac outlets on the unit itself so I could have power even if the ship's distribution system was compromised.

The above electrical items were all mounted on the control box that houses the control relays and voltage regulator.

A 120 deg F, Klixon, normally open thermoswitch (available at Grainger) on the exhaust hose (held on with a spring around the hose) wired to shut down the unit if the hose gets hot above 120 deg F (indicating a seawater flow failure). The engine block will not get hot enough fast enough to shut down the unit before damage to the exhaust hose happens if seawater is suddenly cut off as by a plastic bag, etc. This has saved me several times.

A pre-start lube oil pressure pump to pump up the lube oil pressure in the engine when you press the "prime" button. This is a 12 VDC gear pump I bought from Depco. "They say" 80% of the wear happens in the first few seconds of operation due to dry bearings.

A ball valve and piping to drain the oil easily for oil changes (every 200 hours).

A compound fuel pressure gauge downstream of the secondary (engine mounted) filter to tell how plugged the secondary filter is.


I would like to have:

The oil filter to screw "up" instead of "sideways" so the oil wouldn't make such a mess when I change the filter.

A little funnel and tube to carry away to the bilge the seawater leakage from the mechanical seal on the seawater pump. These seals, on the main engine too, always seem to leak somewhat. Even when I replace them, sooner or later they leak again, but small leaks. Until they get substantial, I prefer to let them leak but carry the drippings away with a funnel and tube to keep the nearby metal from rusting.


As for your relay. This is common in stand-by power systems ashore and is called a "transfer relay" to transfer the load from the mains to the generator. Personally, except for protective devices, I shy away from automatic things in general because I want to be fully aware of what is going on. I have is a rotary manual transfer switch with "shore power", "25 KW", "8 KW", and "grounded" positions. Before I move the switch I strip all loads via the circuit breaker panel. This protects the transfer switch from arcing and also starts the new power source with no loads. I then re-apply the loads.

Another consideration comes into play if you have an inverter. My Trace synchronizes itself to the external power source when one is available and actually aids the external source for short heavy loads such as motor starting. I quote:

"External Transfer Relays"

It is not acceptable to switch the AC input from one AC source to another while the inverter is connected. This applies whether the inverter is in battery charging mode or inverter mode. Switching the AC input from one source to another can result in a loss of synchronization that can cause a severe overcurrent condition that is far worse than short circuiting the inverter. Two separate AC inputs are provided to eliminate the need for use of external transfer relays. If a transfer relay is used, it must provide a center "off" position that causes a loss of input power to the inverter for a period of at least 100 milliseconds. This will allow the inverter to disconnect from the original AC input and then re-synchronize to the new AC source even thought the same AC input terminal is being used. During the transition period, the inverter will have to operate the load while it re-synchronizes to the new AC source (about a thirty-second period at the minimum). Most transfer relays will switch too fast for the inverter to detect - and will cause the inverter to lose synchronization with the AC source. This is indicated by the inverter shutting down upon transfer and the red overcurrent LED indicator flashing or turning on.

Manual, hand operated transfer switches may be acceptable since the transfer time can be slow enough for the inverter to detect. The switch must go through a center "off" position. They are often used to switch from one generator to another. Since the inverter has a separate AC input for a utility grid, a transfer switch is not required to switch from the utility grid to a back-up generator. The inverter will not allow the generator to be connected to the utility - if both are available, the generator will be disconnected and the inverter will be connect to the utility on AC INPUT 1."
 

....

A passage in the manual that cautions against connecting the output of the inverter to the AC mains. I recall that it said the damage resulting from such a connection is "massive and obvious and NOT covered under the warranty".