Triskel power generation system on Distant Shores III

[Fuss]

Originally Posted by noelex 77

Thanks for the details.

That is about 4kw from the front of the engine and a further 1.5 kw from the propshaft. 135hp is larger than my main engine but that is still very impressive.

Do you monitor EGT? Are there any management problems? How old is the system? Do you dial the output down for example if motoring into a strong wind and head-sea?

I agree about the many advantages over the Triskel system such redundancy, ease of repair and simplicity all at a much lower cost. I would not have thought this amount of electrical power could be extracted reliably from such a simple system that has to also function providing propulsion, but obviously it has worked in your case.

No I’m not monitoring the exhaust temp. It’s 8 years old but I imagine the large frame leece neville might burn up if I installed lithium batteries. I never dial it down except the propshaft alternator has the regulator set to bulk around 27.5 I think, just so it does not do the main work under engine , the propshaft alt can be manually switched off and the other 2 can also be switched off at the helm but I never do this. Engine battery does no work except start so it’s charged by a small charger that works when the house bank is over 26 volts.
Officially for a 50 ft 27 ton boat the motors too big but after having this, it gives a great reserve of engine power safety.

[a64pilot]

Originally Posted by wingssail

A64, Cruising has gotten too easy. When people had to navigate by sextant it took a little skill and dedication go cruising. Now anyone with some money can do it, if not well.



And suffer some inconvenience? Why would they, they didn't at home.



But they often find that cruising is not to their liking. The boat is used less and less each year (grandchildren and Norstrom sales are common excuses) and soon the boat is for sale. We see the same boats recycled every few years.

I think it’s always been that way, or at least since the common person began to cruise.
But in truth the Family issues are hard to get away from, it has us where we are for now, and when our Som was run over by a hit and run driver a year and a half ago, I thought cruising was done before it even started.
Stuff happens, always has, but I understand what your saying, like the Woman who can’t understand how anyone would want to live that way, meaning anchored out.
I should have said something, but it’s not my way.

[Fuss]

Originally Posted by noelex 77

This has just been my experience. Cruising sailors waiting in port for marine generator repairs are not unusual. Your solution of a cheap petrol generator has advantages. If it breaks, throw it away and buy another.

Main diesel engines also need attention, but boat owners can repair and service many problems themselves and if stuck any mechanic can work on a yacht marine propulsion engine especially if it is a basic non common rail engine. The parts are typically easy and quick to obtain.

Marine generators have more specific parts and the combination of diesel engine and electronics leaves third world mechanics out of their depth. There are often multiple protection devices such as an automatic shut off with low oil pressure or poor cooling water flow. While desirable for autonomous operation these systems cause problems in a marine environment. This is often further complicated by restricted access. Generators are frequently tucked into smaller spaces. Marine generators need to run at a specific rpm to achieve a stable alternating wave form. As well as the generator itself there are multiple systems such as battery chargers and electrical switching that needs to function correctly for the system as a whole to work. There is a lot that can go wrong.

In any case the main engine is essential (although there are some rare and very brave/hardy souls who would disagree ) whereas a generator is optional. Any associated generator hassles are self inflicted .

In short, the long term reliability of marine generators is not great in my experience. If you can do without the complication this is a worthwhile goal, but the compromises involved with the alternatives are not for everyone.



To be clear, I am not a great fan of the Triskel system. Personally I think a simpler solution is superior, but the Triskel (and similar systems) provide alternatives that have not previously been available so they deserve some consideration and evaluation.

There is no perfect answer to marine power generation, only alternatives with different compromises.

Unless you have some real generators like northern lights, kohler etc, you will have problems. I could go on about all the changes needed but there is really only one question....

What does your generator do when something blocks the water supply?
If the answer is, rips all the blades off the impeller, then you have a non marinised , day sailor generator that is not suitable for long distance travel.

[a64pilot]

Originally Posted by Fuss

Unless you have some real generators like northern lights, kohler etc, you will have problems. I could go on about all the changes needed but there is really only one question....

What does your generator do when something blocks the water supply?
If the answer is, rips all the blades off the impeller, then you have a non marinised , day sailor generator that is not suitable for long distance travel.

It shuts down when it overheats.
The reason is because I think an impeller pump on a generator is foolish. So I use a march AC Air Conditioner pump instead, identical to the one my Air Conditioner uses so one spare covers both.
However my propulsion motor (Yanmar) will rip all the blades off it’s impeller pump, then an alarm will sound as it overheats.
So, I’m to take it that it’s a day sailor propulsion motor, not suitable for long distance travel, all motors with impeller pumps are?

However, just curious, which generators won’t rip the blades off of their impeller pumps?

[Fuss]

I talked about generators not main engines. your main engine should give a warning when it overheats but not shutdown otherwise it’s been designed wrong

[Fuss]

Your one doesn’t rip the blades off

[Fuss]

The way I solved the ripping the blades off was to use the oil pressure warning shutdown system by paralleling this to a pressure switch on the seawater supply after the pump. If you turn off the seacock the generator shuts down immediately which means impellers last nearly for ever.
It’s not as good as your March pump solution though...that’s still better in my opinion.
Now just for comparison, let’s talk about the way the marine generator company addressed overheating problems... they installed a sensor on the exhaust. So what happens is the following. A lack of seawater removes all impeller blades after 20 seconds, the motor carries on of course until 2 minutes 30 is reached, at which point the generator shuts down due to a hot exhaust.
Im not exaggerating with the 20 seconds!

[JimBean]

Hi, What's actually in this Triskell alternator that enables it to make so much power? Does any one know? What is the unit itself made out of?

[OceanPlanet]

Originally Posted by JimBean

Hi, What's actually in this Triskell alternator that enables it to make so much power? Does any one know? What is the unit itself made out of?

A big factor is that it's running at up to 56V, which is more efficient. For instance, another high-output 56V product is the American Power Systems (APS) HPI-160-56V. It's very compact and can fit into most stock alternator positions. Attached graph shows impressive output (also over 8kW). However, note that it has to spin really fast to reach those #'s. Their 28V HPI does bit better at lower rpm however peak output in kW isn't nearly as much.

The Integrel is able to reach it's output at much lower rpm than the HPI 56V, utilizing a special type of rotor that....well...I don't know if I'm allowed to say. Not that I fully understand it anyhow...

[a64pilot]

I wonder where 56V comes from? I know at one time Mercedes and one or two others were playing with the idea of a 42V system for cars.
Does the Triskel use Diodes, or does it have another electronics box that converts AC I assume to DC?

Then finally, maybe stupid question but why not 120VAC?

The Triskel does seem to be a lot smaller than my 6KVA generator head, I wonder how it’s cooled being so small?

Rare earth magnets?

Average run of the mill alternator is 55% efficient, some better, but the Triskel is 85%? I assume that is at the alternator and there are further efficiency losses as I assume it has to convert voltage?

[Dockhead]

Originally Posted by a64pilot

I wonder where 56V comes from? . . .

56v is nominal 48v. Just like 24v nominal alternators are often called 28v in the trade.

[OceanPlanet]

Charging voltage for "48V" batteries typically will run even higher than 56V. For example, 4x12V in series with a target charge voltage of 14.4ea is 57.6V (4 x 14.4 = 57.6).

[a64pilot]

Originally Posted by Dockhead

56v is nominal 48v. Just like 24v nominal alternators are often called 28v in the trade.

And 12 is 14, got it.

[a64pilot]

Originally Posted by Dockhead

56v is nominal 48v. Just like 24v nominal alternators are often called 28v in the trade.

I had a very similar issue with an FAA inspector during an inspection, he asked what voltage is the aircraft? I said 28. He said wrong it’s 24.
It took awhile for him to understand 12V batteries run in 14V systems, 24 on 28 etc.

[Dockhead]

Originally Posted by OceanPlanet

Charging voltage for "48V" batteries typically will run even higher than 56V. For example, 4x12V in series with a target charge voltage of 14.4ea is 57.6V (4 x 14.4 = 57.6).

Sure, it's just a different "nominal" voltage.


But I understand why alternator makers use 14v, 28v and 56v as their nominal voltages, rather than 12v, 24v, and 48v like we do -- that is closer to a normal output during bulk charging so a more convenient number for approximate power calculations.


We say 12v and 24v because that's closer to the voltage we will normally get from lead batteries while we're discharging them and in the middle of the discharge cycle.