Reality check for my little generator

[crayiii]

I have a dealer installed Purguro 9000. I have specs that range from 8.5kw to 12kw from various sources. My guess is 8.5kw is wishful thinking.

When the dealer installed it, the voltage drop was to great for aircons, battery charger, and watermaker (110v WM) so they upped the capacitor size to a 45uf.

That put the no-load voltage at 133v. As load is added, it drops to 123 at 50%.

The no load RPM sits just under 3700 at 60-62hz.

At 60% load, the RPMs fluxuate between 3600 and 3540 with hz at 59-60. That's at about 42 amps.

As the boat swings in and out of the sun and solar come on/off the few amps change from the charger can be heard in the generator as it goes under load, the RPM dips to 3480 hz to 56-57 then it bounces back up. I think that's normal?

If I go higher than 42 amps (shown as 63% load), the little generator starts to struggle. Now the RPMs and hz didp further so I back off.

I can live with 42 amps but I've always been told it's best to run a generator at a high load

Is this just what I should expect from this generator? It seems like the spec sheet is a pipe dream!

I'm getting a quote for a northern lights gender but it will completely fill the locker.

Am I getting expected results for this little guy?

[a64pilot]

You can tell by manually operating the governor, it’s most often an adjustable rod that moves of course with engine RPM, it will be in the wide open position when the engine is off.
Load the generator up to 42 amps, then if you can move the governor arm quite a bit and the engine accelerate briskly, then you have a governor issue, it may just be adjusted incorrectly.
However as I suspect, you can move the arm only a little and the engine may only accelerate just a little, then that ‘s all the engine can do.

42 amps at 120 V is 5,000W. It should make more than that if it’s an 8.5 KW generator.
If it can only make 42 amps, then in my opinion being loaded to 20 amps is plenty, you don’t have to or want to run the snot out of a motor for long life, but you do want to load one up every now and again.
For decades trucks would idle all night long and still get a million miles out of an engine, I believe it’s because after idling all night long, they hit the road in the morning.

[crayiii]

I can get more out of it, it just starts sounding overworked.

The 42 amps that I have it running at is almost 100% motor loads. Aircons pumps and large watermaker pumps. I'm wondering if this is an issue.

[a64pilot]

Amps should be amps, whether motor or resistive.
Kick your water heater on and borrow an electric grill to see.

[Shenandoah52]

Originally Posted by a64pilot

For decades trucks would idle all night long and still get a million miles out of an engine, I believe it’s because after idling all night long, they hit the road in the morning.

Pardon the interruption
A64pilot, thought you might get a kick out of this... I sold my Massey Ferguson 135 tractor 2 years ago to a guy who owned a tow truck company and a wrecking yard. While we were discussing the tractor I said something along the lines of, "Well, when you do your next oil change on the tractor..." and he cut me off immediately and said, "I never do oil changes. See that truck right there (pointing to his Class 7 roll-off still idling) that truck has 950,000 miles on it and I've never changed the oil." I look over at his wife and she nods in agreement. I was completely dumbfounded.

I don't think I'd like to test his theory out, but that was sure a mind-blower.

[crayiii]

After looking at the throttle stops it looks like the locking bolts vibrated lose and it was jambed. I'll take a crack at it in the morning but I think it was being prevented from increasing throttle as high as it needed.

I found a manual on line for the engine (not Paguro) and it says to set the no load max RPMs at 3800 in order to have 3600 at full load. I'll see what I can do.

[crayiii]

There's still gap in the throttle and I can move it and it throttles up. No matter the load, the throttle doesn't move on it's own.

[Sailmonkey]

Originally Posted by crayiii

There's still gap in the throttle and I can move it and it throttles up. No matter the load, the throttle doesn't move on it's own.

The throttle lever won’t move on it’s own, it only puts more tension into the governor spring allowing more fuel to be delivered.

This thing operates by increasing the fuel delivered to maintain speed. When the speed drops the governor weights are pulled in (flyball governor). The weights being pulled to center increases the fuel until the set speed is again achieved.

The problem is that you’re trying to maintain a precise speed with a imprecise instrument (at least at the scale you have). Large flyball governors can be quite precise.


Sorry meant centrifugal governor

[crayiii]

Ahh, so part of my expectation issues with this generator.

I was on another boat this evening that had a Northern Lights genset rated the same as mine. Oh boy. All I can say is not even in the same league. Quiet, smooth and Rock solid RPM.

[Lepke]

The truck not changing oil is probably using a bypass filter that get changed. A common bypass filter used by truckers is a roll of paper towels, or custom roll of paper in a canister. Besides trapping dirt the rolls also hold water. I centrifuge my oil and never change it. But the oil does get tested.

[a64pilot]

I think the guy with the truck was joking, I used to work at a warehouse as a kid driving a forklift, it was sort of a running joke that the trucks were out there changing their oil, meaning leaks of course.
Many said they never change their oil the truck does it itself.

High bypass filter can greatly extend oil change interval, especially in engines that are run very often and for long intervals, like trucks or delivery boats etc.
They will filter out nearly all the particles large enough to cause wear, but oil will still deteriorate over time, often from acid that comes from water vapor and burning fuel byproducts, but a very high quality oil can go a very long time, many do oil analysis and generally the change oil point is when the TBN or total base number and the TAN or total acid number cross on a graph, higher TBN oils will last longer of course. However ever since the introduction of ULSD, high TBN oils are a specialty oil and not commonly available to the public.
For most of us with our gallon and a half oil capacity etc and 500 hours or less per year of engine use, high bypass filtration and centrifuges just don’t make sense money wise, but if your running thousands of hours per year and your oil capacity is measured in 55 gl drums, well then it makes a lot of sense.

On the generator if there is throttle left, well then for whatever reason your governor isn’t calling for it, I’ve seen governor set ups that taking the arm off and moving if a couple of teeth and reassembling will make it work better, of course the arm has to be readjusted.
If at a working load the governor arm and the fuel control arm isn’t close to a 90 degree angle to the connecting rod, that can make the governor less effective, cause of course the governor will get the most travel at the fuel control if it’s at a 90 degree.
Plus if there are several attachment holes in the governor arm, moving it out, as in lengthening the arm will make the governor more effective and more likely to hold set RPM. If it were over speeding, then of course shortening the arm will reduce its effectiveness and slow the motor down.

Many “higher end” generators may actually have an RPM control that actually reads RPM and controls the fuel control electronically, which can be a whole lot more accurate than a mechanical governor.
Also they way the control voltage can be a lot more accurate than a generator that’s voltage is controlled by a capacitor.
The downside is of course more expensive, harder to diagnose and repair and quite a bit more expensive to replace electronic boards than a capacitor.

However for smooth, quiet running and voltage and frequency stability, you just can’t compare a light duty generator like my Nexgen to a Northern Lights, but the Northern Lights is much more expensive, much heavier, and much larger.

Strangely the little portable Honda is the most stable in frequency and voltage of any small generator that I’ve ever seen, it’s as accurate if not more so than grid power.

[model 10]

[QUOTE=Sailmonkey;ve). Large flyball governors can be quite precise [/QUOTE]

Even small ones. Propeller aircraft engine rpm is controlled by a flyweight gov. The flyweight set is probably only 2" wide

[crayiii]

There are no connections on the throttle arm.

[Sailmonkey]

Originally Posted by crayiii

There are no connections on the throttle arm.

The governor is internal to the engine.

[crayiii]

Originally Posted by Sailmonkey

The governor is internal to the engine.

I think it may still be a fuel pump issue. I replaced the large pump that had failed with the small Facet pump I had in board and that got me to 50% load. In looking at the specs for the Facet pump, it's 7gph but only 1-2 psi.

It has to pull fuel from the fuel tank that is below it by 2 feet and 20 feet away. Then it has to push it up 2 feet and about 15 feet away to the racor filter.

I may be asking too much of it?

I plan on walking around the island today to find a different pump. What psi should I be looking for?