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Built-in generators

Andrew Norton follows up last month’s article about portable generators with a look at built-in generators.

If you’re going to invest in a built-in genset, then I recommend only diesel and never a petrol unit. At the risk of offending manufacturers of petrol units, having seen how quickly a fibreglass boat burned to the waterline when its leaking petrol fuel system ignited (and felt the immense heat standing even 10m upwind) I would never ever have a petrol genset in the bilge of a yacht.

Portable petrol gensets are fine because they’re normally stored in a cockpit locker and only used on the deck, out in the open where any fumes from the fuel tank breather instantly vent to the atmosphere. But although petrol is lighter than air and quickly rises, any stray spark from the alternator brushes or windings can easily ignite vapours from the carburettor. Besides, if your yacht’s auxiliary engine is a diesel, why would you have the complications of a separate fuel tank when the genset could feed from the main tankage?

However, to avoid the potential for cross-contamination most genset manufacturers recommend installing a dedicated fuel tank.

Why a built-in genset?The main reasons why anyone would choose a built-in genset is to power appliances that can’t be supplied by the auxiliary engine’s alternator, such as a full-sized microwave oven or aircon for tropical cruising.

Not having gas or alcohol onboard to fuel a stove is a real step towards a non-explosive cabin atmosphere. My first yacht had an propane gas stove and while I never had leakage problems it always gave me the creeps when lighting it. At 120 RON or Research Octane Number (premium unleaded car fuel is only up to 98 RON), propane or LPG is incredibly explosive and being heavier than air finds its way into every crevice in a bilge. Alcohol is less volatile but has a much lower calorific value per

litre, resulting in sometimes painfully slow cooking.

In my opinion if you like cooking with gas then buy a butane-canister-powered single-burner stove from your local camping store and use it only on deck. At 98 RON butane is far less volatile than propane.

As I mentioned in part one, having an auxiliary engine-driven alternator capable of supplying electrical loads such as a galley hotplate via an inverter still will not place enough load on even a 40hp diesel, resulting in cylinder bore glazing down the track through excessive injector fuel spray relative to engine load.

The answer is a built-in diesel genset and the smallest units start at around 1.7 kW (Kilowatts) or 2.0 kVA (1000 x volts/amps) of rated or continuous output, whereas the most powerful portable inverter petrol genset weighing less than 30kg is Yamaha’s 2.5 kVA EF2800i described in part one.

Running an air-conditioner in the tropics is one reason to have a generator.

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Of course, just like installing an auxiliary engine a built-in genset requires the same attention to detail, such as routing fuel lines and the exhaust pipe (again a waterlock system is normally needed because the genset is mounted below the static waterline) and connecting battery wiring. At least you don’t have to worry about correct propshaft alignment.

Fixed rpm or inverter?As with the portable gensets discussed in part one, onboard gensets are either fixed rpm or inverter with engines in the latter type revving only as fast as needed to power the appliances connected. All the gensets in this review are single phase and designed to power normal household appliances, whereas three-phase power is needed to power welding units and if you have a steel yacht that requires repairs a portable three-phase genset in addition to the built-in unit would be the way to go.

Compact fixed rpm AC gensets have been around since the sixties when transistorisation reduced alternator control components to an acceptable size. Fixed rpm gensets rev at either 3000 or 3600 rpm to produce 230-240 volts and 50 Hertz (cycles per second) or 110 volts and 60 Hz for the US market.

They are relatively simple to maintain and service although because the alternator is separate to the engine they’re fairly bulky for their output.

The main drawback with fixed-rpm gensets is that during continuous usage the engine must have no less than 50 percent of rated load (maximum continuous output) on it to prevent glazing the cylinder bores. While in

a small genset this is easy to achieve by leaving a galley hotplate on, when operating power tools or even a microwave oven there will insufficient engine load. So a “dummy” load must be connected to maintain at least 50 percent of the rated load.

Because the engine is spinning at a fixed 3000 or 3600 rpm regardless of load it is fairly noisy, although the soundproofing enclosures fitted to most built-in gensets do reduce engine noise to tolerable levels. But no-matter how good the enclosure is at containing mechanical noise there’s still the noise of the exhaust where it exits the topsides.

Fixed-rpm gensetsIn the past fixed-rpm gensets have had fairly dodgy electricity output quality, with poor voltage and frequency regulation and sine wave forms more akin to jagged mountain peaks than the relatively smooth curves of mains AC power. However, with automatic voltage regulation and better mating of engine torque and power characteristics to the alternator the voltage and frequency stabilisation can be as good as inverter gensets. Some of the gensets mentioned in this guide have sufficiently good sinewave form and voltage and frequency stabilisation

to run a laptop computer and switch mode power supplies as used in compact fluoro lights and multi-stage battery chargers for topping up gel cell or lithium ion batteries.

Inverter gensets differ from fixed-rpm units in that the alternator is incorporated in the engine flywheel and produces three-phase AC power instead of the traditional single-phase of fixed-rpm units. The three-phase power is converted to DC then back to single-phase AC, smoothing out the sine wave form in the process to normally better than mains electricity which from my testing is rarely as good a quality as power generation companies claim it is!

Because of this level of control the engine needs to spin only as fast as needed to supply the appliances connected, significantly reducing fuel consumption relative to load and eliminating the need to have a “dummy” load of at least 50 percent rated to prevent damaging the engine. The genset can also produce its full rated output whether producing 230 volts 50Hz or 110 volts 60Hz, unlike fixed-rpm units where the engine must spin 600 rpm faster to produce 60Hz.

Of course, being diesel with a lesser rpm range than comparable-output petrol engines a minimum load of around 25 percent would still be needed but less of a headache than maintaining minimum 50-percent loading.

Noise levelsNoise levels between petrol-powered fixed-rpm and inverter gensets are significant and at seven metres, for example, Yamaha’s EF2800i has a decibel level of 60 compared to 65 for its now discontinued fixed rpm EF2600

“ Not having gas or alcohol onboard to fuel a stove is a real step towards a non-explosive cabin atmosphere”

Fischer Panda’s 4000s, 5000i and 8000i.

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stablemate, a big difference considering the EF2800i is capable of producing 0.5 kVA or 25 percent more while weighing 12kg or 29 percent less!

But because of the much higher mechanical noise of diesel engines the noise levels of three leading marine genset brands are remarkably similar and much lower than most portable gensets. For example, the Homelite 720W mentioned in part one has a noise level of 66dB at seven metres, rising to 91dB at four metres and requiring the wearing of industrial earmuffs to prevent permanent hearing damage and tinnitus. However, even a basic fixed-rpm 3.5kW or 4.1 kVA diesel genset with soundproofing enclosure has a noise level of only 54dB at seven metres and 64dB at three metres. Only the small portable petrol inverter gensets are

quieter with Yamaha’s EF1000iS, for example, emitting noise levels of 47dB at seven metres. But then it won’t run a galley hotplate or a microwave oven!

As with the petrol units the inverter gensets are much lighter and a 3.5kW or 4.1 kVA inverter genset may weigh 25 percent less than the same-output fixed-rpm unit. That’s a big difference in the bilge of a yacht!

For this article we have limited the maximum genset output covered to 6kW or 7.1 kVA and only 3000 rpm units because 1500-rpm gensets are way too heavy for their output for a yacht.

Air or water cooled?Compared to portable gensets, all of which are air cooled, the built-in diesel gensets have been designed using very different technologies.

For example, fixed-rpm MASE gensets marketed by Power Equipment utilise air-cooled direct-injection Yanmar diesels with an air/sea water heat exchanger to maintain relatively constant temperatures within the soundproofing enclosure. Being air cooled, the engine requires lower maintenance than a water-cooled unit because there are no cooling passage zinc anodes to replace and overall the gensets are lighter than the competition. MASE gensets are made in Italy using Italian alternators which are some of the finest-quality units in the world, a belief backed up by portable genset manufacturers such as Gentech and Toolex.

Fixed-rpm Nannidiesel gensets, marketed by Collins Marine, have direct sea-water cooling of the engine and alternator to reduce noise levels compared to air-cooled engines. For tropical cruising engine temperatures can be controlled more accurately because water is a far superior cooling

medium to air but maintenance is marginally higher. Although Nannidiesel gensets are assembled in France using either German Farymann or Japanese Kubota diesels the alternators are Italian.

Fixed-rpm Fischer Panda gensets, marketed by Power Protection Solutions, utilise direct sea water or fresh water via a heat exchanger. The latter does add some weight to the genset but improves engine performance through higher and more efficient combustion chamber temperatures and a narrower engine cooling range. Lifespan is increased because sea water is kept away from the engine and alternator, but maintenance is higher because there are two cooling water impellers to service. For its small fixed-rpm gensets Fischer Panda uses Farymann diesels from a company that from well back in the last century has been making lifeboat engines.

Fischer Panda’s two inverter gensets under 6kW are both powered by freshwater-cooled diesels in keeping with the upmarket image of these units. Of the three leading brands covered in this review these gensets have the best voltage and frequency stabilisation for sensitive electronic equipment. More on this later. These gensets are powered by Kubota engines.

Fixed-rpm air-cooled gensetsThe smallest MASE model is the single-phase IS 2.6, which has a rated output of 1.7kW or 2.0 kVA and 230 volts at 3000 rpm from a single-cylinder 211cc diesel. Complete with enclosure this unit has a dry weight of only 80kg with length by width by height dimensions of 500 x 380 x 465mm. The noise emission level is 54dB at seven metres although the level at three or four metres and one metre is not mentioned in the tech specs.

Nannidiesel’s DM350 and DM600.

Clean clothes at the push of a button . . . every cruiser’s dream!

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Next up is the single-phase IS 3.5, rated at 2.7kW or 3.1 kVA and 230 volts at 3000 rpm from a 296cc single-cylinder diesel and weighing 96kg. The dimensions are 590 x 406 x 515mm and noise level 54dB at seven metres.

Topping out the range is the single-phase IS 5.0, which is rated at 4.0kW or 4.7 kVA and 230 volts at 3000 rpm, powered by a single-cylinder 406cc diesel and weighs 130kg with dimensions of 675 x 468 x 565mm. Again at seven metres the noise level is 54dB.

However, one aspect of MASE gensets is their voltage and frequency stability. The voltage range can fluctuate from 207 to 253 volts and frequency from 47.5 to 52.5Hz, worse than some fixed-rpm portable gensets and all of the portable inverter units.

Electrical appliances in Australia are designed to operate on 230 to 240 volts and should the voltage drop below 216 switch mode power supply electronics such as computers and even compact fluoro lights won’t function. So while MASE gensets might be suitable for

galley hotplates, microwave ovens and battery charging using linear chargers I’d be wary of connecting switch-mode power supplies such as those in computers and compact fluoros.

At least there’s a separate 12-volt 10-amp battery charging circuit and at 30 degrees the maximum inclination angle is useful for yachties because performance won’t diminish in rough seas.

Fixed-rpm sea-water-cooledDue to be released at the 2011 Sydney International Boat Show, the single-phase Nannidiesel QF3.5 has a rated and maximum output of 2.8kW or 3.5 kVA at 3000 rpm from its 290cc single-cylinder diesel. The dry weight is 105kg and enclosure dimensions 590 x 405 x 515mm. The noise levels are 52dB at seven metres but interestingly not much louder at 56dB at three metres. Even at one metre the noise level of 60dB is quieter than many portable fixed-rpm petrol gensets at seven metres!

Next up is the single-phase QF6.0, producing 4.4kW or 5.5 kVA rated and

230 volts at 3000 rpm from a twin-cylinder 479cc diesel. Having twin cylinders makes a big difference to vibration levels because twins don’t suffer the cyclical reduction of rpm in single-cylinder diesels between the power and compression strokes. Yet the weight is only 128kg with enclosure dimensions of 650 x 480 x 530mm.

Both Nannidiesel gensets have voltage output range of 219 to 241 volts although frequency stabilisation is not mentioned. Also the sinewave shape is not mentioned but as the alternator is an Italian Coeimo, combined with the reasonable voltage stabilisation running switch-mode power-supply appliances should be acceptable. Both units have maximum dynamic (underway) operating angles of 15 degrees.

Fischer Panda’s single-phase 4000s SC PMS produces 3.5kW or 4.1 kVA and 230 volts rated at 3000 rpm from a 298cc single-cylinder diesel and weighs 93kg respectively. The enclosure measures 575 x 365 x 550mm and at seven metres the noise level is 54dB, rising to 64 at three metres and 69dB at one metre.

iSeries Diesel Inverter GeneratorsThe Next Generation of Super Silent Marine Generators

Variable Engine Speed Small Size and Low Weight Inverter Based Technology Fresh Water Cooled Engine Full Feature Digital LCD Remote Control 52dB-54dB Noise Level

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The voltage output range is 219 to 241 volts and frequency 48 to 52Hz so the chances are it should run switch-mode appliances. A maximum inclination angle is not mentioned in the tech specs.

Fixed-rpm fresh-water cooledFischer Panda’s single-phase 4000s FC PMS is the only fixed-rpm genset to have fresh or heat exchanger cooling and this brings the dry weight to 97kg compared to its 4000s SC PMS counterpart.

In all other respects the 4000s FC is the same.

Inverter freshwater-cooledThe only inverter units in this guide are the single-phase Fischer Panda 4000i PMS and 6000i PMS, both having heat exchanger cooling of the engine and alternator.

The 4000i has a rated output of 3.5kW or 4.1 kVA at 2800 rpm from a 309cc single-cylinder diesel and depending on the electrical load the rpm can drop to 2200, substantially reducing engine wear and fuel consumption. The

dry weight is 79kg and the enclosure measures 595 x 390 x 410mm. The noise levels are 54dB at seven metres, 64 at three metres and 68dB at one metre.

The 6000i has a rated output of 5.5kW or 6.5 kVA and is powered by the same twin-cylinder Kubota diesel as Nannidiesel’s QF6.0 but having freshwater cooling and variable engine rpm from 2200 to 2800. Its dry weight is 111kg and the enclosure measures 520 x 440 x 550, so it’s significantly taller due to the upright engine. The noise levels at seven, three and one metre are 52, 62 and 67dB so the 6000i is a very quiet unit.

Both units have voltage ranges of 223 to 236 and frequency ranges of 49 to 51Hz and combined with the sine wave form claimed by Fischer Panda can easily run laptop computers and compact fluoros in addition to galley hotplates and microwave ovens. Both gensets can also run inverter aircon units which are so much more energy efficient than conventional units.

However, no mention of maximum inclination angle is mentioned in the tech specs.

What’s the difference between kW and kVA?Appliances such as fridges and aircon units and power tools such as drills, sanders and planers have PFs of around 0.8 with losses in the motor windings so European manufacturers rate their gensets in kW. Even though a tool may have a running consumption of 500 watts it may actually consume more than 600 watts. This has to be allowed for when combining electrical loads and the European measurement includes this and subsequently is more conservative.

Preferred in Asia and Australia is kVA, which is simply 1000 volts times amps with a Power Factor (PF) of 1.0. For example, when powering incandescent, halogen and compact fluoro lights having a current draw of one amp, this is 240 volts times one amp equalling 240 watts or 0.24 kVA.

Examples of electrical loadsRegardless of the electrical load, when using a standard 240-volt 10-amp

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household power cord the voltage output drops by one volt for every two metres of length. This may not seem like much but with gensets having large voltage ranges it can mean the di�erence between powering and appliance and not. So my advice is to have appliances normally used mounted as close as possible to the genset output sockets.

A single galley hotplate draws around 1500 watts on “high” and a cordless kettle around 2200 watts (both with a PF of 1.0) whereas a full-sized microwave draws 1400 watts (PF 0.8), even though it may be sold as a 650 to 780-watt unit. This is because the magnetron that produces the microwaves is still relatively ine�cient. And even though a 500Lfridge may have a running current of 260 watts (PF 0.8) when the compressor starts it may draw up to 10 times that amount.

A non-inverter aircon unit also has similar cold-start current draw percentage but a soft-start inverter unit can draw a lot less. However, portable genset manufacturers suggest having an alternator output of at least 3.2kW or 4 kVA for non inverter aircon units.

Cold starting and maintenanceCollins Marine thoughtfully supplied an instruction manual for its gensets so the info below is for operating and maintaining Nannidiesel units but

equally applies to water-cooled Kubota engines used in other makes.

Nannidiesel recommends priming the diesel fuel pump if the engine has not been used for several months, then checking the fuel tank, engine coolant tank (heat exchanger models) and engine sump oil level and opening the fuel feed valve and sea water cock. The access panels should be opened and the engine and alternator vented for at least �ve minutes. The battery switch should be turned on and emergency stop o�.

Once the ignition key has been turned to the on position an audible alarm signal will sound and after a few minutes only the oil pressure, battery charge and on indicators will remain lit. Depress the Start button to the midpoint to heat the glowplugs for the indirect injection engine (not applicable to direct injection diesels) for �ve to 20 seconds then fully depress the start button to crank the engine. On starting the warning lights should go out.

I recommend warming a cold engine for a least three minutes before applying load, starting with the least load �rst and progressively increasing loading. Disconnect electrical loads at least two minutes before switching o�

the engine then remember to turn o� the fuel feed and close the sea cock.

Nannidiesel recommends changing the engine oil and �lter after the �rst 20 hours then every 200 or annually when the engine thermostat and fuel pre-�lter should be replaced. If you’re using the engine infrequently then I recommend changing the oil and �lter every six months. An API-CD (American Petroleum Institute) diesel oil having an SAE rating of 15W40 is recommended for ambient temperatures from minus 15 to over 40 degrees.

Valve clearance adjustment is recommended every 400 hours or every two years when the freshwater coolant should also be changed.

Andrew Norton

Andrew has a marine engi-neering background and has contributed to Cruising Helms-man since 1983. He primar-

ily evaluates marine engines and power equipment as well as testing sailing boats and recreational fishing boats and lives in the Lake Macquarie NSW area.

NANNIDIESELNannidiesel marine gensets are available up to 526 kVA with 1500 rpm and three-phase units starting at 7.2 kVA. The engines are a mix of Kubota and Doosan.For more information contact Peter Collins, Collins Marine, Unit 26, 17-21, Bowden St, Alexandria NSW 2015, ph (02) 9319 5222.

FISCHER PANDAFischer Panda offers gensets in either DC (for hybrid power systems) or AC output and fixed-rpm or inverter units to 131 kVA, powered by a mix of Kubota, Yanmar and Deutz diesels. Unusually units to 78 kVA run at 3000 rpm, which after all is what the steam turbines in our coal-fired power stations operate at!

For more information contact Andrew Wilson, Enerdrive Pty Ltd, Unit 11, 1029 Manly RoadTingalpa, Qld, 4173, Phone: 1300 851 535 Mob: 0400 141 290, Email: andrew@enerdrive.com.au

MASEMASE generators are also available in 1500 rpm gensets, starting with the IS 7, which produces 6.2 kW or 7.3 kVA and 230 volts rated from a three-cylinder 1116cc Yanmar diesel. For more information contact Michael Blair, National Marine Sales Manager, 1 Waterway Drive, Coomera QLD 4209, ph (07) 5580 4022, mob 0419 300 299, email michael.blair@powerequipment.com.au

AdditionAl product info And contAct detAils

ABOVE: Where to put your generator is another issue. The owner of this French-built catamaran housed his Paguro generator in the port engine compartment.

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